update from upstream

16 files changed, 566 insertions, 660 deletions

diff --git a/hypervideo_dl/downloader/__init__.py b/hypervideo_dl/downloader/__init__.py
index 96d484d..c34dbce 100644
--- a/hypervideo_dl/downloader/__init__.py
+++ b/hypervideo_dl/downloader/__init__.py
@@ -1,10 +1,4 @@
-from __future__ import unicode_literals
-
-from ..compat import compat_str
-from ..utils import (
-    determine_protocol,
-    NO_DEFAULT
-)
+from ..utils import NO_DEFAULT, determine_protocol
 
 
 def get_suitable_downloader(info_dict, params={}, default=NO_DEFAULT, protocol=None, to_stdout=False):
@@ -29,21 +23,18 @@ def get_suitable_downloader(info_dict, params={}, default=NO_DEFAULT, protocol=N
 # Some of these require get_suitable_downloader
 from .common import FileDownloader
 from .dash import DashSegmentsFD
+from .external import FFmpegFD, get_external_downloader
 from .f4m import F4mFD
 from .fc2 import FC2LiveFD
 from .hls import HlsFD
 from .http import HttpFD
-from .rtmp import RtmpFD
-from .rtsp import RtspFD
 from .ism import IsmFD
 from .mhtml import MhtmlFD
 from .niconico import NiconicoDmcFD
+from .rtmp import RtmpFD
+from .rtsp import RtspFD
 from .websocket import WebSocketFragmentFD
 from .youtube_live_chat import YoutubeLiveChatFD
-from .external import (
-    get_external_downloader,
-    FFmpegFD,
-)
 
 PROTOCOL_MAP = {
     'rtmp': RtmpFD,
@@ -68,10 +59,11 @@ PROTOCOL_MAP = {
 
 def shorten_protocol_name(proto, simplify=False):
     short_protocol_names = {
-        'm3u8_native': 'm3u8_n',
-        'rtmp_ffmpeg': 'rtmp_f',
+        'm3u8_native': 'm3u8',
+        'm3u8': 'm3u8F',
+        'rtmp_ffmpeg': 'rtmpF',
         'http_dash_segments': 'dash',
-        'http_dash_segments_generator': 'dash_g',
+        'http_dash_segments_generator': 'dashG',
         'niconico_dmc': 'dmc',
         'websocket_frag': 'WSfrag',
     }
@@ -79,6 +71,7 @@ def shorten_protocol_name(proto, simplify=False):
         short_protocol_names.update({
             'https': 'http',
             'ftps': 'ftp',
+            'm3u8': 'm3u8',  # Reverse above m3u8 mapping
             'm3u8_native': 'm3u8',
             'http_dash_segments_generator': 'dash',
             'rtmp_ffmpeg': 'rtmp',
@@ -93,13 +86,13 @@ def _get_suitable_downloader(info_dict, protocol, params, default):
     if default is NO_DEFAULT:
         default = HttpFD
 
-    # if (info_dict.get('start_time') or info_dict.get('end_time')) and not info_dict.get('requested_formats') and FFmpegFD.can_download(info_dict):
-    #     return FFmpegFD
+    if (info_dict.get('section_start') or info_dict.get('section_end')) and FFmpegFD.can_download(info_dict):
+        return FFmpegFD
 
     info_dict['protocol'] = protocol
     downloaders = params.get('external_downloader')
     external_downloader = (
-        downloaders if isinstance(downloaders, compat_str) or downloaders is None
+        downloaders if isinstance(downloaders, str) or downloaders is None
         else downloaders.get(shorten_protocol_name(protocol, True), downloaders.get('default')))
 
     if external_downloader is None:
diff --git a/hypervideo_dl/downloader/common.py b/hypervideo_dl/downloader/common.py
index 7cef3e8..72d4822 100644
--- a/hypervideo_dl/downloader/common.py
+++ b/hypervideo_dl/downloader/common.py
@@ -1,30 +1,39 @@
-from __future__ import division, unicode_literals
-
+import contextlib
+import errno
+import functools
 import os
+import random
 import re
 import time
-import random
-import errno
 
+from ..minicurses import (
+    BreaklineStatusPrinter,
+    MultilineLogger,
+    MultilinePrinter,
+    QuietMultilinePrinter,
+)
 from ..utils import (
+    IDENTITY,
+    NO_DEFAULT,
+    LockingUnsupportedError,
+    Namespace,
+    RetryManager,
+    classproperty,
     decodeArgument,
     encodeFilename,
-    error_to_compat_str,
     format_bytes,
+    join_nonempty,
+    parse_bytes,
+    remove_start,
     sanitize_open,
     shell_quote,
     timeconvert,
     timetuple_from_msec,
-)
-from ..minicurses import (
-    MultilineLogger,
-    MultilinePrinter,
-    QuietMultilinePrinter,
-    BreaklineStatusPrinter
+    try_call,
 )
 
 
-class FileDownloader(object):
+class FileDownloader:
     """File Downloader class.
 
     File downloader objects are the ones responsible of downloading the
@@ -39,6 +48,7 @@ class FileDownloader(object):
     verbose:            Print additional info to stdout.
     quiet:              Do not print messages to stdout.
     ratelimit:          Download speed limit, in bytes/sec.
+    continuedl:         Attempt to continue downloads if possible
     throttledratelimit: Assume the download is being throttled below this speed (bytes/sec)
     retries:            Number of times to retry for HTTP error 5xx
     file_access_retries:   Number of times to retry on file access error
@@ -62,6 +72,7 @@ class FileDownloader(object):
                         useful for bypassing bandwidth throttling imposed by
                         a webserver (experimental)
     progress_template:  See YoutubeDL.py
+    retry_sleep_functions: See YoutubeDL.py
 
     Subclasses of this one must re-define the real_download method.
     """
@@ -71,21 +82,51 @@ class FileDownloader(object):
 
     def __init__(self, ydl, params):
         """Create a FileDownloader object with the given options."""
-        self.ydl = ydl
+        self._set_ydl(ydl)
         self._progress_hooks = []
         self.params = params
         self._prepare_multiline_status()
         self.add_progress_hook(self.report_progress)
 
+    def _set_ydl(self, ydl):
+        self.ydl = ydl
+
+        for func in (
+            'deprecation_warning',
+            'deprecated_feature',
+            'report_error',
+            'report_file_already_downloaded',
+            'report_warning',
+            'to_console_title',
+            'to_stderr',
+            'trouble',
+            'write_debug',
+        ):
+            if not hasattr(self, func):
+                setattr(self, func, getattr(ydl, func))
+
+    def to_screen(self, *args, **kargs):
+        self.ydl.to_screen(*args, quiet=self.params.get('quiet'), **kargs)
+
+    __to_screen = to_screen
+
+    @classproperty
+    def FD_NAME(cls):
+        return re.sub(r'(?<=[a-z])(?=[A-Z])', '_', cls.__name__[:-2]).lower()
+
     @staticmethod
     def format_seconds(seconds):
+        if seconds is None:
+            return ' Unknown'
         time = timetuple_from_msec(seconds * 1000)
         if time.hours > 99:
             return '--:--:--'
-        if not time.hours:
-            return '%02d:%02d' % time[1:-1]
         return '%02d:%02d:%02d' % time[:-1]
 
+    @classmethod
+    def format_eta(cls, seconds):
+        return f'{remove_start(cls.format_seconds(seconds), "00:"):>8s}'
+
     @staticmethod
     def calc_percent(byte_counter, data_len):
         if data_len is None:
@@ -94,11 +135,7 @@ class FileDownloader(object):
 
     @staticmethod
     def format_percent(percent):
-        if percent is None:
-            return '---.-%'
-        elif percent == 100:
-            return '100%'
-        return '%6s' % ('%3.1f%%' % percent)
+        return '  N/A%' if percent is None else f'{percent:>5.1f}%'
 
     @staticmethod
     def calc_eta(start, now, total, current):
@@ -113,12 +150,6 @@ class FileDownloader(object):
         return int((float(total) - float(current)) / rate)
 
     @staticmethod
-    def format_eta(eta):
-        if eta is None:
-            return '--:--'
-        return FileDownloader.format_seconds(eta)
-
-    @staticmethod
     def calc_speed(start, now, bytes):
         dif = now - start
         if bytes == 0 or dif < 0.001:  # One millisecond
@@ -127,13 +158,11 @@ class FileDownloader(object):
 
     @staticmethod
     def format_speed(speed):
-        if speed is None:
-            return '%10s' % '---b/s'
-        return '%10s' % ('%s/s' % format_bytes(speed))
+        return ' Unknown B/s' if speed is None else f'{format_bytes(speed):>10s}/s'
 
     @staticmethod
     def format_retries(retries):
-        return 'inf' if retries == float('inf') else '%.0f' % retries
+        return 'inf' if retries == float('inf') else int(retries)
 
     @staticmethod
     def best_block_size(elapsed_time, bytes):
@@ -151,33 +180,7 @@ class FileDownloader(object):
     @staticmethod
     def parse_bytes(bytestr):
         """Parse a string indicating a byte quantity into an integer."""
-        matchobj = re.match(r'(?i)^(\d+(?:\.\d+)?)([kMGTPEZY]?)$', bytestr)
-        if matchobj is None:
-            return None
-        number = float(matchobj.group(1))
-        multiplier = 1024.0 ** 'bkmgtpezy'.index(matchobj.group(2).lower())
-        return int(round(number * multiplier))
-
-    def to_screen(self, *args, **kargs):
-        self.ydl.to_screen(*args, quiet=self.params.get('quiet'), **kargs)
-
-    def to_stderr(self, message):
-        self.ydl.to_stderr(message)
-
-    def to_console_title(self, message):
-        self.ydl.to_console_title(message)
-
-    def trouble(self, *args, **kargs):
-        self.ydl.trouble(*args, **kargs)
-
-    def report_warning(self, *args, **kargs):
-        self.ydl.report_warning(*args, **kargs)
-
-    def report_error(self, *args, **kargs):
-        self.ydl.report_error(*args, **kargs)
-
-    def write_debug(self, *args, **kargs):
-        self.ydl.write_debug(*args, **kargs)
+        parse_bytes(bytestr)
 
     def slow_down(self, start_time, now, byte_counter):
         """Sleep if the download speed is over the rate limit."""
@@ -211,30 +214,31 @@ class FileDownloader(object):
         return filename + '.ytdl'
 
     def wrap_file_access(action, *, fatal=False):
-        def outer(func):
-            def inner(self, *args, **kwargs):
-                file_access_retries = self.params.get('file_access_retries', 0)
-                retry = 0
-                while True:
-                    try:
-                        return func(self, *args, **kwargs)
-                    except (IOError, OSError) as err:
-                        retry = retry + 1
-                        if retry > file_access_retries or err.errno not in (errno.EACCES, errno.EINVAL):
-                            if not fatal:
-                                self.report_error(f'unable to {action} file: {err}')
-                                return
-                            raise
-                        self.to_screen(
-                            f'[download] Unable to {action} file due to file access error. '
-                            f'Retrying (attempt {retry} of {self.format_retries(file_access_retries)}) ...')
-                        time.sleep(0.01)
-            return inner
-        return outer
+        def error_callback(err, count, retries, *, fd):
+            return RetryManager.report_retry(
+                err, count, retries, info=fd.__to_screen,
+                warn=lambda e: (time.sleep(0.01), fd.to_screen(f'[download] Unable to {action} file: {e}')),
+                error=None if fatal else lambda e: fd.report_error(f'Unable to {action} file: {e}'),
+                sleep_func=fd.params.get('retry_sleep_functions', {}).get('file_access'))
+
+        def wrapper(self, func, *args, **kwargs):
+            for retry in RetryManager(self.params.get('file_access_retries'), error_callback, fd=self):
+                try:
+                    return func(self, *args, **kwargs)
+                except OSError as err:
+                    if err.errno in (errno.EACCES, errno.EINVAL):
+                        retry.error = err
+                        continue
+                    retry.error_callback(err, 1, 0)
+
+        return functools.partial(functools.partialmethod, wrapper)
 
     @wrap_file_access('open', fatal=True)
     def sanitize_open(self, filename, open_mode):
-        return sanitize_open(filename, open_mode)
+        f, filename = sanitize_open(filename, open_mode)
+        if not getattr(f, 'locked', None):
+            self.write_debug(f'{LockingUnsupportedError.msg}. Proceeding without locking', only_once=True)
+        return f, filename
 
     @wrap_file_access('remove')
     def try_remove(self, filename):
@@ -261,10 +265,8 @@ class FileDownloader(object):
         # Ignore obviously invalid dates
         if filetime == 0:
             return
-        try:
+        with contextlib.suppress(Exception):
             os.utime(filename, (time.time(), filetime))
-        except Exception:
-            pass
         return filetime
 
     def report_destination(self, filename):
@@ -277,26 +279,26 @@ class FileDownloader(object):
         elif self.ydl.params.get('logger'):
             self._multiline = MultilineLogger(self.ydl.params['logger'], lines)
         elif self.params.get('progress_with_newline'):
-            self._multiline = BreaklineStatusPrinter(self.ydl._out_files['screen'], lines)
+            self._multiline = BreaklineStatusPrinter(self.ydl._out_files.out, lines)
         else:
-            self._multiline = MultilinePrinter(self.ydl._out_files['screen'], lines, not self.params.get('quiet'))
+            self._multiline = MultilinePrinter(self.ydl._out_files.out, lines, not self.params.get('quiet'))
         self._multiline.allow_colors = self._multiline._HAVE_FULLCAP and not self.params.get('no_color')
 
     def _finish_multiline_status(self):
         self._multiline.end()
 
-    _progress_styles = {
-        'downloaded_bytes': 'light blue',
-        'percent': 'light blue',
-        'eta': 'yellow',
-        'speed': 'green',
-        'elapsed': 'bold white',
-        'total_bytes': '',
-        'total_bytes_estimate': '',
-    }
+    ProgressStyles = Namespace(
+        downloaded_bytes='light blue',
+        percent='light blue',
+        eta='yellow',
+        speed='green',
+        elapsed='bold white',
+        total_bytes='',
+        total_bytes_estimate='',
+    )
 
     def _report_progress_status(self, s, default_template):
-        for name, style in self._progress_styles.items():
+        for name, style in self.ProgressStyles.items_:
             name = f'_{name}_str'
             if name not in s:
                 continue
@@ -320,78 +322,73 @@ class FileDownloader(object):
             self._multiline.stream, self._multiline.allow_colors, *args, **kwargs)
 
     def report_progress(self, s):
+        def with_fields(*tups, default=''):
+            for *fields, tmpl in tups:
+                if all(s.get(f) is not None for f in fields):
+                    return tmpl
+            return default
+
+        _format_bytes = lambda k: f'{format_bytes(s.get(k)):>10s}'
+
         if s['status'] == 'finished':
             if self.params.get('noprogress'):
                 self.to_screen('[download] Download completed')
-            msg_template = '100%%'
-            if s.get('total_bytes') is not None:
-                s['_total_bytes_str'] = format_bytes(s['total_bytes'])
-                msg_template += ' of %(_total_bytes_str)s'
-            if s.get('elapsed') is not None:
-                s['_elapsed_str'] = self.format_seconds(s['elapsed'])
-                msg_template += ' in %(_elapsed_str)s'
-            s['_percent_str'] = self.format_percent(100)
-            self._report_progress_status(s, msg_template)
-            return
+            speed = try_call(lambda: s['total_bytes'] / s['elapsed'])
+            s.update({
+                'speed': speed,
+                '_speed_str': self.format_speed(speed).strip(),
+                '_total_bytes_str': _format_bytes('total_bytes'),
+                '_elapsed_str': self.format_seconds(s.get('elapsed')),
+                '_percent_str': self.format_percent(100),
+            })
+            self._report_progress_status(s, join_nonempty(
+                '100%%',
+                with_fields(('total_bytes', 'of %(_total_bytes_str)s')),
+                with_fields(('elapsed', 'in %(_elapsed_str)s')),
+                with_fields(('speed', 'at %(_speed_str)s')),
+                delim=' '))
 
         if s['status'] != 'downloading':
             return
 
-        if s.get('eta') is not None:
-            s['_eta_str'] = self.format_eta(s['eta'])
-        else:
-            s['_eta_str'] = 'Unknown'
-
-        if s.get('total_bytes') and s.get('downloaded_bytes') is not None:
-            s['_percent_str'] = self.format_percent(100 * s['downloaded_bytes'] / s['total_bytes'])
-        elif s.get('total_bytes_estimate') and s.get('downloaded_bytes') is not None:
-            s['_percent_str'] = self.format_percent(100 * s['downloaded_bytes'] / s['total_bytes_estimate'])
-        else:
-            if s.get('downloaded_bytes') == 0:
-                s['_percent_str'] = self.format_percent(0)
-            else:
-                s['_percent_str'] = 'Unknown %'
-
-        if s.get('speed') is not None:
-            s['_speed_str'] = self.format_speed(s['speed'])
-        else:
-            s['_speed_str'] = 'Unknown speed'
-
-        if s.get('total_bytes') is not None:
-            s['_total_bytes_str'] = format_bytes(s['total_bytes'])
-            msg_template = '%(_percent_str)s of %(_total_bytes_str)s at %(_speed_str)s ETA %(_eta_str)s'
-        elif s.get('total_bytes_estimate') is not None:
-            s['_total_bytes_estimate_str'] = format_bytes(s['total_bytes_estimate'])
-            msg_template = '%(_percent_str)s of ~%(_total_bytes_estimate_str)s at %(_speed_str)s ETA %(_eta_str)s'
-        else:
-            if s.get('downloaded_bytes') is not None:
-                s['_downloaded_bytes_str'] = format_bytes(s['downloaded_bytes'])
-                if s.get('elapsed'):
-                    s['_elapsed_str'] = self.format_seconds(s['elapsed'])
-                    msg_template = '%(_downloaded_bytes_str)s at %(_speed_str)s (%(_elapsed_str)s)'
-                else:
-                    msg_template = '%(_downloaded_bytes_str)s at %(_speed_str)s'
-            else:
-                msg_template = '%(_percent_str)s at %(_speed_str)s ETA %(_eta_str)s'
-        if s.get('fragment_index') and s.get('fragment_count'):
-            msg_template += ' (frag %(fragment_index)s/%(fragment_count)s)'
-        elif s.get('fragment_index'):
-            msg_template += ' (frag %(fragment_index)s)'
+        s.update({
+            '_eta_str': self.format_eta(s.get('eta')).strip(),
+            '_speed_str': self.format_speed(s.get('speed')),
+            '_percent_str': self.format_percent(try_call(
+                lambda: 100 * s['downloaded_bytes'] / s['total_bytes'],
+                lambda: 100 * s['downloaded_bytes'] / s['total_bytes_estimate'],
+                lambda: s['downloaded_bytes'] == 0 and 0)),
+            '_total_bytes_str': _format_bytes('total_bytes'),
+            '_total_bytes_estimate_str': _format_bytes('total_bytes_estimate'),
+            '_downloaded_bytes_str': _format_bytes('downloaded_bytes'),
+            '_elapsed_str': self.format_seconds(s.get('elapsed')),
+        })
+
+        msg_template = with_fields(
+            ('total_bytes', '%(_percent_str)s of %(_total_bytes_str)s at %(_speed_str)s ETA %(_eta_str)s'),
+            ('total_bytes_estimate', '%(_percent_str)s of ~%(_total_bytes_estimate_str)s at %(_speed_str)s ETA %(_eta_str)s'),
+            ('downloaded_bytes', 'elapsed', '%(_downloaded_bytes_str)s at %(_speed_str)s (%(_elapsed_str)s)'),
+            ('downloaded_bytes', '%(_downloaded_bytes_str)s at %(_speed_str)s'),
+            default='%(_percent_str)s at %(_speed_str)s ETA %(_eta_str)s')
+
+        msg_template += with_fields(
+            ('fragment_index', 'fragment_count', ' (frag %(fragment_index)s/%(fragment_count)s)'),
+            ('fragment_index', ' (frag %(fragment_index)s)'))
         self._report_progress_status(s, msg_template)
 
     def report_resuming_byte(self, resume_len):
         """Report attempt to resume at given byte."""
         self.to_screen('[download] Resuming download at byte %s' % resume_len)
 
-    def report_retry(self, err, count, retries):
-        """Report retry in case of HTTP error 5xx"""
-        self.to_screen(
-            '[download] Got server HTTP error: %s. Retrying (attempt %d of %s) ...'
-            % (error_to_compat_str(err), count, self.format_retries(retries)))
-
-    def report_file_already_downloaded(self, *args, **kwargs):
-        """Report file has already been fully downloaded."""
-        return self.ydl.report_file_already_downloaded(*args, **kwargs)
+    def report_retry(self, err, count, retries, frag_index=NO_DEFAULT, fatal=True):
+        """Report retry"""
+        is_frag = False if frag_index is NO_DEFAULT else 'fragment'
+        RetryManager.report_retry(
+            err, count, retries, info=self.__to_screen,
+            warn=lambda msg: self.__to_screen(f'[download] Got error: {msg}'),
+            error=IDENTITY if not fatal else lambda e: self.report_error(f'\r[download] Got error: {e}'),
+            sleep_func=self.params.get('retry_sleep_functions', {}).get(is_frag or 'http'),
+            suffix=f'fragment{"s" if frag_index is None else f" {frag_index}"}' if is_frag else None)
 
     def report_unable_to_resume(self):
         """Report it was impossible to resume download."""
@@ -431,25 +428,16 @@ class FileDownloader(object):
                 self._finish_multiline_status()
                 return True, False
 
-        if subtitle is False:
-            min_sleep_interval = self.params.get('sleep_interval')
-            if min_sleep_interval:
-                max_sleep_interval = self.params.get('max_sleep_interval', min_sleep_interval)
-                sleep_interval = random.uniform(min_sleep_interval, max_sleep_interval)
-                self.to_screen(
-                    '[download] Sleeping %s seconds ...' % (
-                        int(sleep_interval) if sleep_interval.is_integer()
-                        else '%.2f' % sleep_interval))
-                time.sleep(sleep_interval)
+        if subtitle:
+            sleep_interval = self.params.get('sleep_interval_subtitles') or 0
         else:
-            sleep_interval_sub = 0
-            if type(self.params.get('sleep_interval_subtitles')) is int:
-                sleep_interval_sub = self.params.get('sleep_interval_subtitles')
-            if sleep_interval_sub > 0:
-                self.to_screen(
-                    '[download] Sleeping %s seconds ...' % (
-                        sleep_interval_sub))
-                time.sleep(sleep_interval_sub)
+            min_sleep_interval = self.params.get('sleep_interval') or 0
+            sleep_interval = random.uniform(
+                min_sleep_interval, self.params.get('max_sleep_interval') or min_sleep_interval)
+        if sleep_interval > 0:
+            self.to_screen(f'[download] Sleeping {sleep_interval:.2f} seconds ...')
+            time.sleep(sleep_interval)
+
         ret = self.real_download(filename, info_dict)
         self._finish_multiline_status()
         return ret, True
@@ -459,8 +447,7 @@ class FileDownloader(object):
         raise NotImplementedError('This method must be implemented by subclasses')
 
     def _hook_progress(self, status, info_dict):
-        if not self._progress_hooks:
-            return
+        # Ideally we want to make a copy of the dict, but that is too slow
         status['info_dict'] = info_dict
         # youtube-dl passes the same status object to all the hooks.
         # Some third party scripts seems to be relying on this.
@@ -482,4 +469,4 @@ class FileDownloader(object):
         if exe is None:
             exe = os.path.basename(str_args[0])
 
-        self.write_debug('%s command line: %s' % (exe, shell_quote(str_args)))
+        self.write_debug(f'{exe} command line: {shell_quote(str_args)}')
diff --git a/hypervideo_dl/downloader/dash.py b/hypervideo_dl/downloader/dash.py
index a845ee7..4328d73 100644
--- a/hypervideo_dl/downloader/dash.py
+++ b/hypervideo_dl/downloader/dash.py
@@ -1,10 +1,9 @@
-from __future__ import unicode_literals
 import time
+import urllib.parse
 
-from ..downloader import get_suitable_downloader
+from . import get_suitable_downloader
 from .fragment import FragmentFD
-
-from ..utils import urljoin
+from ..utils import update_url_query, urljoin
 
 
 class DashSegmentsFD(FragmentFD):
@@ -42,24 +41,29 @@ class DashSegmentsFD(FragmentFD):
                 self._prepare_and_start_frag_download(ctx, fmt)
             ctx['start'] = real_start
 
-            fragments_to_download = self._get_fragments(fmt, ctx)
+            extra_query = None
+            extra_param_to_segment_url = info_dict.get('extra_param_to_segment_url')
+            if extra_param_to_segment_url:
+                extra_query = urllib.parse.parse_qs(extra_param_to_segment_url)
+
+            fragments_to_download = self._get_fragments(fmt, ctx, extra_query)
 
             if real_downloader:
                 self.to_screen(
-                    '[%s] Fragment downloads will be delegated to %s' % (self.FD_NAME, real_downloader.get_basename()))
+                    f'[{self.FD_NAME}] Fragment downloads will be delegated to {real_downloader.get_basename()}')
                 info_dict['fragments'] = list(fragments_to_download)
                 fd = real_downloader(self.ydl, self.params)
                 return fd.real_download(filename, info_dict)
 
             args.append([ctx, fragments_to_download, fmt])
 
-        return self.download_and_append_fragments_multiple(*args)
+        return self.download_and_append_fragments_multiple(*args, is_fatal=lambda idx: idx == 0)
 
     def _resolve_fragments(self, fragments, ctx):
         fragments = fragments(ctx) if callable(fragments) else fragments
         return [next(iter(fragments))] if self.params.get('test') else fragments
 
-    def _get_fragments(self, fmt, ctx):
+    def _get_fragments(self, fmt, ctx, extra_query):
         fragment_base_url = fmt.get('fragment_base_url')
         fragments = self._resolve_fragments(fmt['fragments'], ctx)
 
@@ -72,9 +76,12 @@ class DashSegmentsFD(FragmentFD):
             if not fragment_url:
                 assert fragment_base_url
                 fragment_url = urljoin(fragment_base_url, fragment['path'])
+            if extra_query:
+                fragment_url = update_url_query(fragment_url, extra_query)
 
             yield {
                 'frag_index': frag_index,
+                'fragment_count': fragment.get('fragment_count'),
                 'index': i,
                 'url': fragment_url,
             }
diff --git a/hypervideo_dl/downloader/external.py b/hypervideo_dl/downloader/external.py
index b99dc37..75257a7 100644
--- a/hypervideo_dl/downloader/external.py
+++ b/hypervideo_dl/downloader/external.py
@@ -1,5 +1,4 @@
-from __future__ import unicode_literals
-
+import enum
 import os.path
 import re
 import subprocess
@@ -7,30 +6,35 @@ import sys
 import time
 
 from .fragment import FragmentFD
-from ..compat import (
-    compat_setenv,
-    compat_str,
-)
-from ..postprocessor.ffmpeg import FFmpegPostProcessor, EXT_TO_OUT_FORMATS
+from ..compat import functools
+from ..postprocessor.ffmpeg import EXT_TO_OUT_FORMATS, FFmpegPostProcessor
 from ..utils import (
+    Popen,
+    RetryManager,
+    _configuration_args,
+    check_executable,
     classproperty,
+    cli_bool_option,
     cli_option,
     cli_valueless_option,
-    cli_bool_option,
-    _configuration_args,
     determine_ext,
-    encodeFilename,
     encodeArgument,
+    encodeFilename,
     handle_youtubedl_headers,
-    check_executable,
-    Popen,
     remove_end,
+    traverse_obj,
 )
 
 
+class Features(enum.Enum):
+    TO_STDOUT = enum.auto()
+    MULTIPLE_FORMATS = enum.auto()
+
+
 class ExternalFD(FragmentFD):
     SUPPORTED_PROTOCOLS = ('http', 'https', 'ftp', 'ftps')
-    can_download_to_stdout = False
+    SUPPORTED_FEATURES = ()
+    _CAPTURE_STDERR = True
 
     def real_download(self, filename, info_dict):
         self.report_destination(filename)
@@ -56,7 +60,7 @@ class ExternalFD(FragmentFD):
             }
             if filename != '-':
                 fsize = os.path.getsize(encodeFilename(tmpfilename))
-                self.to_screen('\r[%s] Downloaded %s bytes' % (self.get_basename(), fsize))
+                self.to_screen(f'\r[{self.get_basename()}] Downloaded {fsize} bytes')
                 self.try_rename(tmpfilename, filename)
                 status.update({
                     'downloaded_bytes': fsize,
@@ -78,7 +82,7 @@ class ExternalFD(FragmentFD):
     def EXE_NAME(cls):
         return cls.get_basename()
 
-    @property
+    @functools.cached_property
     def exe(self):
         return self.EXE_NAME
 
@@ -94,9 +98,11 @@ class ExternalFD(FragmentFD):
 
     @classmethod
     def supports(cls, info_dict):
-        return (
-            (cls.can_download_to_stdout or not info_dict.get('to_stdout'))
-            and info_dict['protocol'] in cls.SUPPORTED_PROTOCOLS)
+        return all((
+            not info_dict.get('to_stdout') or Features.TO_STDOUT in cls.SUPPORTED_FEATURES,
+            '+' not in info_dict['protocol'] or Features.MULTIPLE_FORMATS in cls.SUPPORTED_FEATURES,
+            all(proto in cls.SUPPORTED_PROTOCOLS for proto in info_dict['protocol'].split('+')),
+        ))
 
     @classmethod
     def can_download(cls, info_dict, path=None):
@@ -123,33 +129,28 @@ class ExternalFD(FragmentFD):
         self._debug_cmd(cmd)
 
         if 'fragments' not in info_dict:
-            p = Popen(cmd, stderr=subprocess.PIPE)
-            _, stderr = p.communicate_or_kill()
-            if p.returncode != 0:
-                self.to_stderr(stderr.decode('utf-8', 'replace'))
-            return p.returncode
+            _, stderr, returncode = Popen.run(
+                cmd, text=True, stderr=subprocess.PIPE if self._CAPTURE_STDERR else None)
+            if returncode and stderr:
+                self.to_stderr(stderr)
+            return returncode
 
-        fragment_retries = self.params.get('fragment_retries', 0)
         skip_unavailable_fragments = self.params.get('skip_unavailable_fragments', True)
 
-        count = 0
-        while count <= fragment_retries:
-            p = Popen(cmd, stderr=subprocess.PIPE)
-            _, stderr = p.communicate_or_kill()
-            if p.returncode == 0:
+        retry_manager = RetryManager(self.params.get('fragment_retries'), self.report_retry,
+                                     frag_index=None, fatal=not skip_unavailable_fragments)
+        for retry in retry_manager:
+            _, stderr, returncode = Popen.run(cmd, text=True, stderr=subprocess.PIPE)
+            if not returncode:
                 break
             # TODO: Decide whether to retry based on error code
             # https://aria2.github.io/manual/en/html/aria2c.html#exit-status
-            self.to_stderr(stderr.decode('utf-8', 'replace'))
-            count += 1
-            if count <= fragment_retries:
-                self.to_screen(
-                    '[%s] Got error. Retrying fragments (attempt %d of %s)...'
-                    % (self.get_basename(), count, self.format_retries(fragment_retries)))
-        if count > fragment_retries:
-            if not skip_unavailable_fragments:
-                self.report_error('Giving up after %s fragment retries' % fragment_retries)
-                return -1
+            if stderr:
+                self.to_stderr(stderr)
+            retry.error = Exception()
+            continue
+        if not skip_unavailable_fragments and retry_manager.error:
+            return -1
 
         decrypt_fragment = self.decrypter(info_dict)
         dest, _ = self.sanitize_open(tmpfilename, 'wb')
@@ -157,7 +158,7 @@ class ExternalFD(FragmentFD):
             fragment_filename = '%s-Frag%d' % (tmpfilename, frag_index)
             try:
                 src, _ = self.sanitize_open(fragment_filename, 'rb')
-            except IOError as err:
+            except OSError as err:
                 if skip_unavailable_fragments and frag_index > 1:
                     self.report_skip_fragment(frag_index, err)
                     continue
@@ -174,12 +175,13 @@ class ExternalFD(FragmentFD):
 
 class CurlFD(ExternalFD):
     AVAILABLE_OPT = '-V'
+    _CAPTURE_STDERR = False  # curl writes the progress to stderr
 
     def _make_cmd(self, tmpfilename, info_dict):
         cmd = [self.exe, '--location', '-o', tmpfilename, '--compressed']
         if info_dict.get('http_headers') is not None:
             for key, val in info_dict['http_headers'].items():
-                cmd += ['--header', '%s: %s' % (key, val)]
+                cmd += ['--header', f'{key}: {val}']
 
         cmd += self._bool_option('--continue-at', 'continuedl', '-', '0')
         cmd += self._valueless_option('--silent', 'noprogress')
@@ -198,16 +200,6 @@ class CurlFD(ExternalFD):
         cmd += ['--', info_dict['url']]
         return cmd
 
-    def _call_downloader(self, tmpfilename, info_dict):
-        cmd = [encodeArgument(a) for a in self._make_cmd(tmpfilename, info_dict)]
-
-        self._debug_cmd(cmd)
-
-        # curl writes the progress to stderr so don't capture it.
-        p = Popen(cmd)
-        p.communicate_or_kill()
-        return p.returncode
-
 
 class AxelFD(ExternalFD):
     AVAILABLE_OPT = '-V'
@@ -216,7 +208,7 @@ class AxelFD(ExternalFD):
         cmd = [self.exe, '-o', tmpfilename]
         if info_dict.get('http_headers') is not None:
             for key, val in info_dict['http_headers'].items():
-                cmd += ['-H', '%s: %s' % (key, val)]
+                cmd += ['-H', f'{key}: {val}']
         cmd += self._configuration_args()
         cmd += ['--', info_dict['url']]
         return cmd
@@ -229,7 +221,7 @@ class WgetFD(ExternalFD):
         cmd = [self.exe, '-O', tmpfilename, '-nv', '--no-cookies', '--compression=auto']
         if info_dict.get('http_headers') is not None:
             for key, val in info_dict['http_headers'].items():
-                cmd += ['--header', '%s: %s' % (key, val)]
+                cmd += ['--header', f'{key}: {val}']
         cmd += self._option('--limit-rate', 'ratelimit')
         retry = self._option('--tries', 'retries')
         if len(retry) == 2:
@@ -240,7 +232,7 @@ class WgetFD(ExternalFD):
         proxy = self.params.get('proxy')
         if proxy:
             for var in ('http_proxy', 'https_proxy'):
-                cmd += ['--execute', '%s=%s' % (var, proxy)]
+                cmd += ['--execute', f'{var}={proxy}']
         cmd += self._valueless_option('--no-check-certificate', 'nocheckcertificate')
         cmd += self._configuration_args()
         cmd += ['--', info_dict['url']]
@@ -260,6 +252,10 @@ class Aria2cFD(ExternalFD):
         check_results = (not re.search(feature, manifest) for feature in UNSUPPORTED_FEATURES)
         return all(check_results)
 
+    @staticmethod
+    def _aria2c_filename(fn):
+        return fn if os.path.isabs(fn) else f'.{os.path.sep}{fn}'
+
     def _make_cmd(self, tmpfilename, info_dict):
         cmd = [self.exe, '-c',
                '--console-log-level=warn', '--summary-interval=0', '--download-result=hide',
@@ -271,7 +267,7 @@ class Aria2cFD(ExternalFD):
 
         if info_dict.get('http_headers') is not None:
             for key, val in info_dict['http_headers'].items():
-                cmd += ['--header', '%s: %s' % (key, val)]
+                cmd += ['--header', f'{key}: {val}']
         cmd += self._option('--max-overall-download-limit', 'ratelimit')
         cmd += self._option('--interface', 'source_address')
         cmd += self._option('--all-proxy', 'proxy')
@@ -288,11 +284,9 @@ class Aria2cFD(ExternalFD):
         # https://github.com/aria2/aria2/issues/1373
         dn = os.path.dirname(tmpfilename)
         if dn:
-            if not os.path.isabs(dn):
-                dn = '.%s%s' % (os.path.sep, dn)
-            cmd += ['--dir', dn + os.path.sep]
+            cmd += ['--dir', self._aria2c_filename(dn) + os.path.sep]
         if 'fragments' not in info_dict:
-            cmd += ['--out', '.%s%s' % (os.path.sep, os.path.basename(tmpfilename))]
+            cmd += ['--out', self._aria2c_filename(os.path.basename(tmpfilename))]
         cmd += ['--auto-file-renaming=false']
 
         if 'fragments' in info_dict:
@@ -301,11 +295,11 @@ class Aria2cFD(ExternalFD):
             url_list = []
             for frag_index, fragment in enumerate(info_dict['fragments']):
                 fragment_filename = '%s-Frag%d' % (os.path.basename(tmpfilename), frag_index)
-                url_list.append('%s\n\tout=%s' % (fragment['url'], fragment_filename))
+                url_list.append('%s\n\tout=%s' % (fragment['url'], self._aria2c_filename(fragment_filename)))
             stream, _ = self.sanitize_open(url_list_file, 'wb')
-            stream.write('\n'.join(url_list).encode('utf-8'))
+            stream.write('\n'.join(url_list).encode())
             stream.close()
-            cmd += ['-i', url_list_file]
+            cmd += ['-i', self._aria2c_filename(url_list_file)]
         else:
             cmd += ['--', info_dict['url']]
         return cmd
@@ -320,13 +314,13 @@ class HttpieFD(ExternalFD):
 
         if info_dict.get('http_headers') is not None:
             for key, val in info_dict['http_headers'].items():
-                cmd += ['%s:%s' % (key, val)]
+                cmd += [f'{key}:{val}']
         return cmd
 
 
 class FFmpegFD(ExternalFD):
     SUPPORTED_PROTOCOLS = ('http', 'https', 'ftp', 'ftps', 'm3u8', 'm3u8_native', 'rtsp', 'rtmp', 'rtmp_ffmpeg', 'mms', 'http_dash_segments')
-    can_download_to_stdout = True
+    SUPPORTED_FEATURES = (Features.TO_STDOUT, Features.MULTIPLE_FORMATS)
 
     @classmethod
     def available(cls, path=None):
@@ -334,10 +328,6 @@ class FFmpegFD(ExternalFD):
         # Fixme: This may be wrong when --ffmpeg-location is used
         return FFmpegPostProcessor().available
 
-    @classmethod
-    def supports(cls, info_dict):
-        return all(proto in cls.SUPPORTED_PROTOCOLS for proto in info_dict['protocol'].split('+'))
-
     def on_process_started(self, proc, stdin):
         """ Override this in subclasses  """
         pass
@@ -368,9 +358,11 @@ class FFmpegFD(ExternalFD):
         if not self.params.get('verbose'):
             args += ['-hide_banner']
 
-        args += info_dict.get('_ffmpeg_args', [])
+        args += traverse_obj(info_dict, ('downloader_options', 'ffmpeg_args'), default=[])
 
-        # This option exists only for compatibility. Extractors should use `_ffmpeg_args` instead
+        # These exists only for compatibility. Extractors should use
+        # info_dict['downloader_options']['ffmpeg_args'] instead
+        args += info_dict.get('_ffmpeg_args') or []
         seekable = info_dict.get('_seekable')
         if seekable is not None:
             # setting -seekable prevents ffmpeg from guessing if the server
@@ -380,20 +372,15 @@ class FFmpegFD(ExternalFD):
             # http://trac.ffmpeg.org/ticket/6125#comment:10
             args += ['-seekable', '1' if seekable else '0']
 
-        # start_time = info_dict.get('start_time') or 0
-        # if start_time:
-        #     args += ['-ss', compat_str(start_time)]
-        # end_time = info_dict.get('end_time')
-        # if end_time:
-        #     args += ['-t', compat_str(end_time - start_time)]
-
-        if info_dict.get('http_headers') is not None and re.match(r'^https?://', urls[0]):
-            # Trailing \r\n after each HTTP header is important to prevent warning from ffmpeg/avconv:
-            # [http @ 00000000003d2fa0] No trailing CRLF found in HTTP header.
-            headers = handle_youtubedl_headers(info_dict['http_headers'])
-            args += [
+        http_headers = None
+        if info_dict.get('http_headers'):
+            youtubedl_headers = handle_youtubedl_headers(info_dict['http_headers'])
+            http_headers = [
+                # Trailing \r\n after each HTTP header is important to prevent warning from ffmpeg/avconv:
+                # [http @ 00000000003d2fa0] No trailing CRLF found in HTTP header.
                 '-headers',
-                ''.join('%s: %s\r\n' % (key, val) for key, val in headers.items())]
+                ''.join(f'{key}: {val}\r\n' for key, val in youtubedl_headers.items())
+            ]
 
         env = None
         proxy = self.params.get('proxy')
@@ -411,8 +398,8 @@ class FFmpegFD(ExternalFD):
             # We could switch to the following code if we are able to detect version properly
             # args += ['-http_proxy', proxy]
             env = os.environ.copy()
-            compat_setenv('HTTP_PROXY', proxy, env=env)
-            compat_setenv('http_proxy', proxy, env=env)
+            env['HTTP_PROXY'] = proxy
+            env['http_proxy'] = proxy
 
         protocol = info_dict.get('protocol')
 
@@ -442,20 +429,31 @@ class FFmpegFD(ExternalFD):
             if isinstance(conn, list):
                 for entry in conn:
                     args += ['-rtmp_conn', entry]
-            elif isinstance(conn, compat_str):
+            elif isinstance(conn, str):
                 args += ['-rtmp_conn', conn]
 
+        start_time, end_time = info_dict.get('section_start') or 0, info_dict.get('section_end')
+
         for i, url in enumerate(urls):
+            if http_headers is not None and re.match(r'^https?://', url):
+                args += http_headers
+            if start_time:
+                args += ['-ss', str(start_time)]
+            if end_time:
+                args += ['-t', str(end_time - start_time)]
+
             args += self._configuration_args((f'_i{i + 1}', '_i')) + ['-i', url]
 
-        args += ['-c', 'copy']
+        if not (start_time or end_time) or not self.params.get('force_keyframes_at_cuts'):
+            args += ['-c', 'copy']
+
         if info_dict.get('requested_formats') or protocol == 'http_dash_segments':
             for (i, fmt) in enumerate(info_dict.get('requested_formats') or [info_dict]):
                 stream_number = fmt.get('manifest_stream_number', 0)
                 args.extend(['-map', f'{i}:{stream_number}'])
 
         if self.params.get('test', False):
-            args += ['-fs', compat_str(self._TEST_FILE_SIZE)]
+            args += ['-fs', str(self._TEST_FILE_SIZE)]
 
         ext = info_dict['ext']
         if protocol in ('m3u8', 'm3u8_native'):
@@ -490,24 +488,23 @@ class FFmpegFD(ExternalFD):
         args.append(encodeFilename(ffpp._ffmpeg_filename_argument(tmpfilename), True))
         self._debug_cmd(args)
 
-        proc = Popen(args, stdin=subprocess.PIPE, env=env)
-        if url in ('-', 'pipe:'):
-            self.on_process_started(proc, proc.stdin)
-        try:
-            retval = proc.wait()
-        except BaseException as e:
-            # subprocces.run would send the SIGKILL signal to ffmpeg and the
-            # mp4 file couldn't be played, but if we ask ffmpeg to quit it
-            # produces a file that is playable (this is mostly useful for live
-            # streams). Note that Windows is not affected and produces playable
-            # files (see https://github.com/ytdl-org/youtube-dl/issues/8300).
-            if isinstance(e, KeyboardInterrupt) and sys.platform != 'win32' and url not in ('-', 'pipe:'):
-                proc.communicate_or_kill(b'q')
-            else:
-                proc.kill()
-                proc.wait()
-            raise
-        return retval
+        with Popen(args, stdin=subprocess.PIPE, env=env) as proc:
+            if url in ('-', 'pipe:'):
+                self.on_process_started(proc, proc.stdin)
+            try:
+                retval = proc.wait()
+            except BaseException as e:
+                # subprocces.run would send the SIGKILL signal to ffmpeg and the
+                # mp4 file couldn't be played, but if we ask ffmpeg to quit it
+                # produces a file that is playable (this is mostly useful for live
+                # streams). Note that Windows is not affected and produces playable
+                # files (see https://github.com/ytdl-org/youtube-dl/issues/8300).
+                if isinstance(e, KeyboardInterrupt) and sys.platform != 'win32' and url not in ('-', 'pipe:'):
+                    proc.communicate_or_kill(b'q')
+                else:
+                    proc.kill(timeout=None)
+                raise
+            return retval
 
 
 class AVconvFD(FFmpegFD):
@@ -520,16 +517,14 @@ _BY_NAME = {
     if name.endswith('FD') and name not in ('ExternalFD', 'FragmentFD')
 }
 
-_BY_EXE = {klass.EXE_NAME: klass for klass in _BY_NAME.values()}
-
 
 def list_external_downloaders():
     return sorted(_BY_NAME.keys())
 
 
 def get_external_downloader(external_downloader):
-    """ Given the name of the executable, see whether we support the given
-        downloader . """
-    # Drop .exe extension on Windows
+    """ Given the name of the executable, see whether we support the given downloader """
     bn = os.path.splitext(os.path.basename(external_downloader))[0]
-    return _BY_NAME.get(bn, _BY_EXE.get(bn))
+    return _BY_NAME.get(bn) or next((
+        klass for klass in _BY_NAME.values() if klass.EXE_NAME in bn
+    ), None)
diff --git a/hypervideo_dl/downloader/f4m.py b/hypervideo_dl/downloader/f4m.py
index 0008b7c..306f921 100644
--- a/hypervideo_dl/downloader/f4m.py
+++ b/hypervideo_dl/downloader/f4m.py
@@ -1,23 +1,14 @@
-from __future__ import division, unicode_literals
-
+import base64
 import io
 import itertools
+import struct
 import time
+import urllib.error
+import urllib.parse
 
 from .fragment import FragmentFD
-from ..compat import (
-    compat_b64decode,
-    compat_etree_fromstring,
-    compat_urlparse,
-    compat_urllib_error,
-    compat_urllib_parse_urlparse,
-    compat_struct_pack,
-    compat_struct_unpack,
-)
-from ..utils import (
-    fix_xml_ampersands,
-    xpath_text,
-)
+from ..compat import compat_etree_fromstring
+from ..utils import fix_xml_ampersands, xpath_text
 
 
 class DataTruncatedError(Exception):
@@ -40,13 +31,13 @@ class FlvReader(io.BytesIO):
 
     # Utility functions for reading numbers and strings
     def read_unsigned_long_long(self):
-        return compat_struct_unpack('!Q', self.read_bytes(8))[0]
+        return struct.unpack('!Q', self.read_bytes(8))[0]
 
     def read_unsigned_int(self):
-        return compat_struct_unpack('!I', self.read_bytes(4))[0]
+        return struct.unpack('!I', self.read_bytes(4))[0]
 
     def read_unsigned_char(self):
-        return compat_struct_unpack('!B', self.read_bytes(1))[0]
+        return struct.unpack('!B', self.read_bytes(1))[0]
 
     def read_string(self):
         res = b''
@@ -193,7 +184,7 @@ def build_fragments_list(boot_info):
     first_frag_number = fragment_run_entry_table[0]['first']
     fragments_counter = itertools.count(first_frag_number)
     for segment, fragments_count in segment_run_table['segment_run']:
-        # In some live HDS streams (for example Rai), `fragments_count` is
+        # In some live HDS streams (e.g. Rai), `fragments_count` is
         # abnormal and causing out-of-memory errors. It's OK to change the
         # number of fragments for live streams as they are updated periodically
         if fragments_count == 4294967295 and boot_info['live']:
@@ -208,11 +199,11 @@ def build_fragments_list(boot_info):
 
 
 def write_unsigned_int(stream, val):
-    stream.write(compat_struct_pack('!I', val))
+    stream.write(struct.pack('!I', val))
 
 
 def write_unsigned_int_24(stream, val):
-    stream.write(compat_struct_pack('!I', val)[1:])
+    stream.write(struct.pack('!I', val)[1:])
 
 
 def write_flv_header(stream):
@@ -261,8 +252,6 @@ class F4mFD(FragmentFD):
     A downloader for f4m manifests or AdobeHDS.
     """
 
-    FD_NAME = 'f4m'
-
     def _get_unencrypted_media(self, doc):
         media = doc.findall(_add_ns('media'))
         if not media:
@@ -308,12 +297,12 @@ class F4mFD(FragmentFD):
         # 1. http://live-1-1.rutube.ru/stream/1024/HDS/SD/C2NKsS85HQNckgn5HdEmOQ/1454167650/S-s604419906/move/four/dirs/upper/1024-576p.f4m
         bootstrap_url = node.get('url')
         if bootstrap_url:
-            bootstrap_url = compat_urlparse.urljoin(
+            bootstrap_url = urllib.parse.urljoin(
                 base_url, bootstrap_url)
             boot_info = self._get_bootstrap_from_url(bootstrap_url)
         else:
             bootstrap_url = None
-            bootstrap = compat_b64decode(node.text)
+            bootstrap = base64.b64decode(node.text)
             boot_info = read_bootstrap_info(bootstrap)
         return boot_info, bootstrap_url
 
@@ -343,14 +332,14 @@ class F4mFD(FragmentFD):
         # Prefer baseURL for relative URLs as per 11.2 of F4M 3.0 spec.
         man_base_url = get_base_url(doc) or man_url
 
-        base_url = compat_urlparse.urljoin(man_base_url, media.attrib['url'])
+        base_url = urllib.parse.urljoin(man_base_url, media.attrib['url'])
         bootstrap_node = doc.find(_add_ns('bootstrapInfo'))
         boot_info, bootstrap_url = self._parse_bootstrap_node(
             bootstrap_node, man_base_url)
         live = boot_info['live']
         metadata_node = media.find(_add_ns('metadata'))
         if metadata_node is not None:
-            metadata = compat_b64decode(metadata_node.text)
+            metadata = base64.b64decode(metadata_node.text)
         else:
             metadata = None
 
@@ -378,7 +367,7 @@ class F4mFD(FragmentFD):
             if not live:
                 write_metadata_tag(dest_stream, metadata)
 
-        base_url_parsed = compat_urllib_parse_urlparse(base_url)
+        base_url_parsed = urllib.parse.urlparse(base_url)
 
         self._start_frag_download(ctx, info_dict)
 
@@ -398,9 +387,10 @@ class F4mFD(FragmentFD):
                 query.append(info_dict['extra_param_to_segment_url'])
             url_parsed = base_url_parsed._replace(path=base_url_parsed.path + name, query='&'.join(query))
             try:
-                success, down_data = self._download_fragment(ctx, url_parsed.geturl(), info_dict)
+                success = self._download_fragment(ctx, url_parsed.geturl(), info_dict)
                 if not success:
                     return False
+                down_data = self._read_fragment(ctx)
                 reader = FlvReader(down_data)
                 while True:
                     try:
@@ -417,7 +407,7 @@ class F4mFD(FragmentFD):
                     if box_type == b'mdat':
                         self._append_fragment(ctx, box_data)
                         break
-            except (compat_urllib_error.HTTPError, ) as err:
+            except urllib.error.HTTPError as err:
                 if live and (err.code == 404 or err.code == 410):
                     # We didn't keep up with the live window. Continue
                     # with the next available fragment.
@@ -434,6 +424,4 @@ class F4mFD(FragmentFD):
                     msg = 'Missed %d fragments' % (fragments_list[0][1] - (frag_i + 1))
                     self.report_warning(msg)
 
-        self._finish_frag_download(ctx, info_dict)
-
-        return True
+        return self._finish_frag_download(ctx, info_dict)
diff --git a/hypervideo_dl/downloader/fc2.py b/hypervideo_dl/downloader/fc2.py
index 157bcf2..f9763de 100644
--- a/hypervideo_dl/downloader/fc2.py
+++ b/hypervideo_dl/downloader/fc2.py
@@ -1,5 +1,3 @@
-from __future__ import division, unicode_literals
-
 import threading
 
 from .common import FileDownloader
@@ -20,6 +18,9 @@ class FC2LiveFD(FileDownloader):
         heartbeat_state = [None, 1]
 
         def heartbeat():
+            if heartbeat_state[1] < 0:
+                return
+
             try:
                 heartbeat_state[1] += 1
                 ws.send('{"name":"heartbeat","arguments":{},"id":%d}' % heartbeat_state[1])
@@ -38,4 +39,8 @@ class FC2LiveFD(FileDownloader):
             'ws': None,
             'protocol': 'live_ffmpeg',
         })
-        return FFmpegFD(self.ydl, self.params or {}).download(filename, new_info_dict)
+        try:
+            return FFmpegFD(self.ydl, self.params or {}).download(filename, new_info_dict)
+        finally:
+            # stop heartbeating
+            heartbeat_state[1] = -1
diff --git a/hypervideo_dl/downloader/fragment.py b/hypervideo_dl/downloader/fragment.py
index a991c6d..e61bd0e 100644
--- a/hypervideo_dl/downloader/fragment.py
+++ b/hypervideo_dl/downloader/fragment.py
@@ -1,28 +1,20 @@
-from __future__ import division, unicode_literals
-
+import concurrent.futures
+import contextlib
 import http.client
 import json
 import math
 import os
+import struct
 import time
-
-try:
-    import concurrent.futures
-    can_threaded_download = True
-except ImportError:
-    can_threaded_download = False
+import urllib.error
 
 from .common import FileDownloader
 from .http import HttpFD
 from ..aes import aes_cbc_decrypt_bytes, unpad_pkcs7
-from ..compat import (
-    compat_os_name,
-    compat_urllib_error,
-    compat_struct_pack,
-)
+from ..compat import compat_os_name
 from ..utils import (
     DownloadError,
-    error_to_compat_str,
+    RetryManager,
     encodeFilename,
     sanitized_Request,
     traverse_obj,
@@ -33,9 +25,7 @@ class HttpQuietDownloader(HttpFD):
     def to_screen(self, *args, **kargs):
         pass
 
-    def report_retry(self, err, count, retries):
-        super().to_screen(
-            f'[download] Got server HTTP error: {err}. Retrying (attempt {count} of {self.format_retries(retries)}) ...')
+    to_console_title = to_screen
 
 
 class FragmentFD(FileDownloader):
@@ -75,9 +65,9 @@ class FragmentFD(FileDownloader):
     """
 
     def report_retry_fragment(self, err, frag_index, count, retries):
-        self.to_screen(
-            '\r[download] Got server HTTP error: %s. Retrying fragment %d (attempt %d of %s) ...'
-            % (error_to_compat_str(err), frag_index, count, self.format_retries(retries)))
+        self.deprecation_warning('hypervideo_dl.downloader.FragmentFD.report_retry_fragment is deprecated. '
+                                 'Use hypervideo_dl.downloader.FileDownloader.report_retry instead')
+        return self.report_retry(err, count, retries, frag_index)
 
     def report_skip_fragment(self, frag_index, err=None):
         err = f' {err};' if err else ''
@@ -131,7 +121,7 @@ class FragmentFD(FileDownloader):
             'request_data': request_data,
             'ctx_id': ctx.get('ctx_id'),
         }
-        success = ctx['dl'].download(fragment_filename, fragment_info_dict)
+        success, _ = ctx['dl'].download(fragment_filename, fragment_info_dict)
         if not success:
             return False
         if fragment_info_dict.get('filetime'):
@@ -140,6 +130,8 @@ class FragmentFD(FileDownloader):
         return True
 
     def _read_fragment(self, ctx):
+        if not ctx.get('fragment_filename_sanitized'):
+            return None
         try:
             down, frag_sanitized = self.sanitize_open(ctx['fragment_filename_sanitized'], 'rb')
         except FileNotFoundError:
@@ -172,21 +164,13 @@ class FragmentFD(FileDownloader):
                 total_frags_str += ' (not including %d ad)' % ad_frags
         else:
             total_frags_str = 'unknown (live)'
-        self.to_screen(
-            '[%s] Total fragments: %s' % (self.FD_NAME, total_frags_str))
+        self.to_screen(f'[{self.FD_NAME}] Total fragments: {total_frags_str}')
         self.report_destination(ctx['filename'])
-        dl = HttpQuietDownloader(
-            self.ydl,
-            {
-                'continuedl': self.params.get('continuedl', True),
-                'quiet': self.params.get('quiet'),
-                'noprogress': True,
-                'ratelimit': self.params.get('ratelimit'),
-                'retries': self.params.get('retries', 0),
-                'nopart': self.params.get('nopart', False),
-                'test': self.params.get('test', False),
-            }
-        )
+        dl = HttpQuietDownloader(self.ydl, {
+            **self.params,
+            'noprogress': True,
+            'test': False,
+        })
         tmpfilename = self.temp_name(ctx['filename'])
         open_mode = 'wb'
         resume_len = 0
@@ -259,6 +243,9 @@ class FragmentFD(FileDownloader):
             if s['status'] not in ('downloading', 'finished'):
                 return
 
+            if not total_frags and ctx.get('fragment_count'):
+                state['fragment_count'] = ctx['fragment_count']
+
             if ctx_id is not None and s.get('ctx_id') != ctx_id:
                 return
 
@@ -308,18 +295,23 @@ class FragmentFD(FileDownloader):
                 self.try_remove(ytdl_filename)
         elapsed = time.time() - ctx['started']
 
-        if ctx['tmpfilename'] == '-':
-            downloaded_bytes = ctx['complete_frags_downloaded_bytes']
+        to_file = ctx['tmpfilename'] != '-'
+        if to_file:
+            downloaded_bytes = os.path.getsize(encodeFilename(ctx['tmpfilename']))
         else:
+            downloaded_bytes = ctx['complete_frags_downloaded_bytes']
+
+        if not downloaded_bytes:
+            if to_file:
+                self.try_remove(ctx['tmpfilename'])
+            self.report_error('The downloaded file is empty')
+            return False
+        elif to_file:
             self.try_rename(ctx['tmpfilename'], ctx['filename'])
-            if self.params.get('updatetime', True):
-                filetime = ctx.get('fragment_filetime')
-                if filetime:
-                    try:
-                        os.utime(ctx['filename'], (time.time(), filetime))
-                    except Exception:
-                        pass
-            downloaded_bytes = os.path.getsize(encodeFilename(ctx['filename']))
+            filetime = ctx.get('fragment_filetime')
+            if self.params.get('updatetime', True) and filetime:
+                with contextlib.suppress(Exception):
+                    os.utime(ctx['filename'], (time.time(), filetime))
 
         self._hook_progress({
             'downloaded_bytes': downloaded_bytes,
@@ -331,6 +323,7 @@ class FragmentFD(FileDownloader):
             'max_progress': ctx.get('max_progress'),
             'progress_idx': ctx.get('progress_idx'),
         }, info_dict)
+        return True
 
     def _prepare_external_frag_download(self, ctx):
         if 'live' not in ctx:
@@ -342,8 +335,7 @@ class FragmentFD(FileDownloader):
                 total_frags_str += ' (not including %d ad)' % ad_frags
         else:
             total_frags_str = 'unknown (live)'
-        self.to_screen(
-            '[%s] Total fragments: %s' % (self.FD_NAME, total_frags_str))
+        self.to_screen(f'[{self.FD_NAME}] Total fragments: {total_frags_str}')
 
         tmpfilename = self.temp_name(ctx['filename'])
 
@@ -362,10 +354,12 @@ class FragmentFD(FileDownloader):
             return _key_cache[url]
 
         def decrypt_fragment(fragment, frag_content):
+            if frag_content is None:
+                return
             decrypt_info = fragment.get('decrypt_info')
             if not decrypt_info or decrypt_info['METHOD'] != 'AES-128':
                 return frag_content
-            iv = decrypt_info.get('IV') or compat_struct_pack('>8xq', fragment['media_sequence'])
+            iv = decrypt_info.get('IV') or struct.pack('>8xq', fragment['media_sequence'])
             decrypt_info['KEY'] = decrypt_info.get('KEY') or _get_key(info_dict.get('_decryption_key_url') or decrypt_info['URI'])
             # Don't decrypt the content in tests since the data is explicitly truncated and it's not to a valid block
             # size (see https://github.com/ytdl-org/youtube-dl/pull/27660). Tests only care that the correct data downloaded,
@@ -376,7 +370,7 @@ class FragmentFD(FileDownloader):
 
         return decrypt_fragment
 
-    def download_and_append_fragments_multiple(self, *args, pack_func=None, finish_func=None):
+    def download_and_append_fragments_multiple(self, *args, **kwargs):
         '''
         @params (ctx1, fragments1, info_dict1), (ctx2, fragments2, info_dict2), ...
                 all args must be either tuple or list
@@ -384,7 +378,7 @@ class FragmentFD(FileDownloader):
         interrupt_trigger = [True]
         max_progress = len(args)
         if max_progress == 1:
-            return self.download_and_append_fragments(*args[0], pack_func=pack_func, finish_func=finish_func)
+            return self.download_and_append_fragments(*args[0], **kwargs)
         max_workers = self.params.get('concurrent_fragment_downloads', 1)
         if max_progress > 1:
             self._prepare_multiline_status(max_progress)
@@ -394,8 +388,7 @@ class FragmentFD(FileDownloader):
             ctx['max_progress'] = max_progress
             ctx['progress_idx'] = idx
             return self.download_and_append_fragments(
-                ctx, fragments, info_dict, pack_func=pack_func, finish_func=finish_func,
-                tpe=tpe, interrupt_trigger=interrupt_trigger)
+                ctx, fragments, info_dict, **kwargs, tpe=tpe, interrupt_trigger=interrupt_trigger)
 
         class FTPE(concurrent.futures.ThreadPoolExecutor):
             # has to stop this or it's going to wait on the worker thread itself
@@ -442,18 +435,12 @@ class FragmentFD(FileDownloader):
         return result
 
     def download_and_append_fragments(
-            self, ctx, fragments, info_dict, *, pack_func=None, finish_func=None,
-            tpe=None, interrupt_trigger=None):
-        if not interrupt_trigger:
-            interrupt_trigger = (True, )
-
-        fragment_retries = self.params.get('fragment_retries', 0)
-        is_fatal = (
-            ((lambda _: False) if info_dict.get('is_live') else (lambda idx: idx == 0))
-            if self.params.get('skip_unavailable_fragments', True) else (lambda _: True))
+            self, ctx, fragments, info_dict, *, is_fatal=(lambda idx: False),
+            pack_func=(lambda content, idx: content), finish_func=None,
+            tpe=None, interrupt_trigger=(True, )):
 
-        if not pack_func:
-            pack_func = lambda frag_content, _: frag_content
+        if not self.params.get('skip_unavailable_fragments', True):
+            is_fatal = lambda _: True
 
         def download_fragment(fragment, ctx):
             if not interrupt_trigger[0]:
@@ -467,31 +454,25 @@ class FragmentFD(FileDownloader):
                 headers['Range'] = 'bytes=%d-%d' % (byte_range['start'], byte_range['end'] - 1)
 
             # Never skip the first fragment
-            fatal, count = is_fatal(fragment.get('index') or (frag_index - 1)), 0
-            while count <= fragment_retries:
-                try:
-                    if self._download_fragment(ctx, fragment['url'], info_dict, headers):
-                        break
-                    return
-                except (compat_urllib_error.HTTPError, http.client.IncompleteRead) as err:
-                    # Unavailable (possibly temporary) fragments may be served.
-                    # First we try to retry then either skip or abort.
-                    # See https://github.com/ytdl-org/youtube-dl/issues/10165,
-                    # https://github.com/ytdl-org/youtube-dl/issues/10448).
-                    count += 1
-                    ctx['last_error'] = err
-                    if count <= fragment_retries:
-                        self.report_retry_fragment(err, frag_index, count, fragment_retries)
-                except DownloadError:
-                    # Don't retry fragment if error occurred during HTTP downloading
-                    # itself since it has own retry settings
-                    if not fatal:
-                        break
-                    raise
+            fatal = is_fatal(fragment.get('index') or (frag_index - 1))
 
-            if count > fragment_retries and fatal:
-                ctx['dest_stream'].close()
-                self.report_error('Giving up after %s fragment retries' % fragment_retries)
+            def error_callback(err, count, retries):
+                if fatal and count > retries:
+                    ctx['dest_stream'].close()
+                self.report_retry(err, count, retries, frag_index, fatal)
+                ctx['last_error'] = err
+
+            for retry in RetryManager(self.params.get('fragment_retries'), error_callback):
+                try:
+                    ctx['fragment_count'] = fragment.get('fragment_count')
+                    if not self._download_fragment(ctx, fragment['url'], info_dict, headers):
+                        return
+                except (urllib.error.HTTPError, http.client.IncompleteRead) as err:
+                    retry.error = err
+                    continue
+                except DownloadError:  # has own retry settings
+                    if fatal:
+                        raise
 
         def append_fragment(frag_content, frag_index, ctx):
             if frag_content:
@@ -508,8 +489,7 @@ class FragmentFD(FileDownloader):
 
         max_workers = math.ceil(
             self.params.get('concurrent_fragment_downloads', 1) / ctx.get('max_progress', 1))
-        if can_threaded_download and max_workers > 1:
-
+        if max_workers > 1:
             def _download_fragment(fragment):
                 ctx_copy = ctx.copy()
                 download_fragment(fragment, ctx_copy)
@@ -517,23 +497,36 @@ class FragmentFD(FileDownloader):
 
             self.report_warning('The download speed shown is only of one thread. This is a known issue and patches are welcome')
             with tpe or concurrent.futures.ThreadPoolExecutor(max_workers) as pool:
-                for fragment, frag_index, frag_filename in pool.map(_download_fragment, fragments):
-                    ctx['fragment_filename_sanitized'] = frag_filename
-                    ctx['fragment_index'] = frag_index
-                    result = append_fragment(decrypt_fragment(fragment, self._read_fragment(ctx)), frag_index, ctx)
-                    if not result:
-                        return False
+                try:
+                    for fragment, frag_index, frag_filename in pool.map(_download_fragment, fragments):
+                        ctx.update({
+                            'fragment_filename_sanitized': frag_filename,
+                            'fragment_index': frag_index,
+                        })
+                        if not append_fragment(decrypt_fragment(fragment, self._read_fragment(ctx)), frag_index, ctx):
+                            return False
+                except KeyboardInterrupt:
+                    self._finish_multiline_status()
+                    self.report_error(
+                        'Interrupted by user. Waiting for all threads to shutdown...', is_error=False, tb=False)
+                    pool.shutdown(wait=False)
+                    raise
         else:
             for fragment in fragments:
                 if not interrupt_trigger[0]:
                     break
-                download_fragment(fragment, ctx)
-                result = append_fragment(decrypt_fragment(fragment, self._read_fragment(ctx)), fragment['frag_index'], ctx)
+                try:
+                    download_fragment(fragment, ctx)
+                    result = append_fragment(
+                        decrypt_fragment(fragment, self._read_fragment(ctx)), fragment['frag_index'], ctx)
+                except KeyboardInterrupt:
+                    if info_dict.get('is_live'):
+                        break
+                    raise
                 if not result:
                     return False
 
         if finish_func is not None:
             ctx['dest_stream'].write(finish_func())
             ctx['dest_stream'].flush()
-        self._finish_frag_download(ctx, info_dict)
-        return True
+        return self._finish_frag_download(ctx, info_dict)
diff --git a/hypervideo_dl/downloader/hls.py b/hypervideo_dl/downloader/hls.py
index f3f32b5..4520edc 100644
--- a/hypervideo_dl/downloader/hls.py
+++ b/hypervideo_dl/downloader/hls.py
@@ -1,23 +1,14 @@
-from __future__ import unicode_literals
-
-import re
-import io
 import binascii
+import io
+import re
+import urllib.parse
 
-from ..downloader import get_suitable_downloader
-from .fragment import FragmentFD
+from . import get_suitable_downloader
 from .external import FFmpegFD
-
-from ..compat import (
-    compat_pycrypto_AES,
-    compat_urlparse,
-)
-from ..utils import (
-    parse_m3u8_attributes,
-    update_url_query,
-    bug_reports_message,
-)
+from .fragment import FragmentFD
 from .. import webvtt
+from ..dependencies import Cryptodome_AES
+from ..utils import bug_reports_message, parse_m3u8_attributes, update_url_query
 
 
 class HlsFD(FragmentFD):
@@ -70,12 +61,18 @@ class HlsFD(FragmentFD):
         s = urlh.read().decode('utf-8', 'ignore')
 
         can_download, message = self.can_download(s, info_dict, self.params.get('allow_unplayable_formats')), None
-        if can_download and not compat_pycrypto_AES and '#EXT-X-KEY:METHOD=AES-128' in s:
-            if FFmpegFD.available():
+        if can_download:
+            has_ffmpeg = FFmpegFD.available()
+            no_crypto = not Cryptodome_AES and '#EXT-X-KEY:METHOD=AES-128' in s
+            if no_crypto and has_ffmpeg:
                 can_download, message = False, 'The stream has AES-128 encryption and pycryptodome is not available'
-            else:
+            elif no_crypto:
                 message = ('The stream has AES-128 encryption and neither ffmpeg nor pycryptodome are available; '
                            'Decryption will be performed natively, but will be extremely slow')
+            elif info_dict.get('extractor_key') == 'Generic' and re.search(r'(?m)#EXT-X-MEDIA-SEQUENCE:(?!0$)', s):
+                install_ffmpeg = '' if has_ffmpeg else 'install ffmpeg and '
+                message = ('Live HLS streams are not supported by the native downloader. If this is a livestream, '
+                           f'please {install_ffmpeg}add "--downloader ffmpeg --hls-use-mpegts" to your command')
         if not can_download:
             has_drm = re.search('|'.join([
                 r'#EXT-X-FAXS-CM:',  # Adobe Flash Access
@@ -102,8 +99,7 @@ class HlsFD(FragmentFD):
         if real_downloader and not real_downloader.supports_manifest(s):
             real_downloader = None
         if real_downloader:
-            self.to_screen(
-                '[%s] Fragment downloads will be delegated to %s' % (self.FD_NAME, real_downloader.get_basename()))
+            self.to_screen(f'[{self.FD_NAME}] Fragment downloads will be delegated to {real_downloader.get_basename()}')
 
         def is_ad_fragment_start(s):
             return (s.startswith('#ANVATO-SEGMENT-INFO') and 'type=ad' in s
@@ -150,7 +146,7 @@ class HlsFD(FragmentFD):
         extra_query = None
         extra_param_to_segment_url = info_dict.get('extra_param_to_segment_url')
         if extra_param_to_segment_url:
-            extra_query = compat_urlparse.parse_qs(extra_param_to_segment_url)
+            extra_query = urllib.parse.parse_qs(extra_param_to_segment_url)
         i = 0
         media_sequence = 0
         decrypt_info = {'METHOD': 'NONE'}
@@ -172,7 +168,7 @@ class HlsFD(FragmentFD):
                     frag_url = (
                         line
                         if re.match(r'^https?://', line)
-                        else compat_urlparse.urljoin(man_url, line))
+                        else urllib.parse.urljoin(man_url, line))
                     if extra_query:
                         frag_url = update_url_query(frag_url, extra_query)
 
@@ -197,10 +193,18 @@ class HlsFD(FragmentFD):
                     frag_url = (
                         map_info.get('URI')
                         if re.match(r'^https?://', map_info.get('URI'))
-                        else compat_urlparse.urljoin(man_url, map_info.get('URI')))
+                        else urllib.parse.urljoin(man_url, map_info.get('URI')))
                     if extra_query:
                         frag_url = update_url_query(frag_url, extra_query)
 
+                    if map_info.get('BYTERANGE'):
+                        splitted_byte_range = map_info.get('BYTERANGE').split('@')
+                        sub_range_start = int(splitted_byte_range[1]) if len(splitted_byte_range) == 2 else byte_range['end']
+                        byte_range = {
+                            'start': sub_range_start,
+                            'end': sub_range_start + int(splitted_byte_range[0]),
+                        }
+
                     fragments.append({
                         'frag_index': frag_index,
                         'url': frag_url,
@@ -210,14 +214,6 @@ class HlsFD(FragmentFD):
                     })
                     media_sequence += 1
 
-                    if map_info.get('BYTERANGE'):
-                        splitted_byte_range = map_info.get('BYTERANGE').split('@')
-                        sub_range_start = int(splitted_byte_range[1]) if len(splitted_byte_range) == 2 else byte_range['end']
-                        byte_range = {
-                            'start': sub_range_start,
-                            'end': sub_range_start + int(splitted_byte_range[0]),
-                        }
-
                 elif line.startswith('#EXT-X-KEY'):
                     decrypt_url = decrypt_info.get('URI')
                     decrypt_info = parse_m3u8_attributes(line[11:])
@@ -225,7 +221,7 @@ class HlsFD(FragmentFD):
                         if 'IV' in decrypt_info:
                             decrypt_info['IV'] = binascii.unhexlify(decrypt_info['IV'][2:].zfill(32))
                         if not re.match(r'^https?://', decrypt_info['URI']):
-                            decrypt_info['URI'] = compat_urlparse.urljoin(
+                            decrypt_info['URI'] = urllib.parse.urljoin(
                                 man_url, decrypt_info['URI'])
                         if extra_query:
                             decrypt_info['URI'] = update_url_query(decrypt_info['URI'], extra_query)
@@ -339,7 +335,7 @@ class HlsFD(FragmentFD):
                             continue
                     block.write_into(output)
 
-                return output.getvalue().encode('utf-8')
+                return output.getvalue().encode()
 
             def fin_fragments():
                 dedup_window = extra_state.get('webvtt_dedup_window')
@@ -350,7 +346,7 @@ class HlsFD(FragmentFD):
                 for cue in dedup_window:
                     webvtt.CueBlock.from_json(cue).write_into(output)
 
-                return output.getvalue().encode('utf-8')
+                return output.getvalue().encode()
 
             self.download_and_append_fragments(
                 ctx, fragments, info_dict, pack_func=pack_fragment, finish_func=fin_fragments)
diff --git a/hypervideo_dl/downloader/http.py b/hypervideo_dl/downloader/http.py
index 591a9b0..95c870e 100644
--- a/hypervideo_dl/downloader/http.py
+++ b/hypervideo_dl/downloader/http.py
@@ -1,29 +1,33 @@
-from __future__ import unicode_literals
-
+import http.client
 import os
+import random
+import socket
 import ssl
 import time
-import random
+import urllib.error
 
 from .common import FileDownloader
-from ..compat import (
-    compat_urllib_error,
-    compat_http_client
-)
 from ..utils import (
     ContentTooShortError,
+    RetryManager,
+    ThrottledDownload,
+    XAttrMetadataError,
+    XAttrUnavailableError,
     encodeFilename,
     int_or_none,
     parse_http_range,
     sanitized_Request,
-    ThrottledDownload,
     try_call,
     write_xattr,
-    XAttrMetadataError,
-    XAttrUnavailableError,
 )
 
-RESPONSE_READ_EXCEPTIONS = (TimeoutError, ConnectionError, ssl.SSLError, compat_http_client.HTTPException)
+RESPONSE_READ_EXCEPTIONS = (
+    TimeoutError,
+    socket.timeout,  # compat: py < 3.10
+    ConnectionError,
+    ssl.SSLError,
+    http.client.HTTPException
+)
 
 
 class HttpFD(FileDownloader):
@@ -69,9 +73,6 @@ class HttpFD(FileDownloader):
 
         ctx.is_resume = ctx.resume_len > 0
 
-        count = 0
-        retries = self.params.get('retries', 0)
-
         class SucceedDownload(Exception):
             pass
 
@@ -134,19 +135,18 @@ class HttpFD(FileDownloader):
                 if has_range:
                     content_range = ctx.data.headers.get('Content-Range')
                     content_range_start, content_range_end, content_len = parse_http_range(content_range)
-                    if content_range_start is not None and range_start == content_range_start:
-                        # Content-Range is present and matches requested Range, resume is possible
-                        accept_content_len = (
+                    # Content-Range is present and matches requested Range, resume is possible
+                    if range_start == content_range_start and (
                             # Non-chunked download
                             not ctx.chunk_size
                             # Chunked download and requested piece or
                             # its part is promised to be served
                             or content_range_end == range_end
-                            or content_len < range_end)
-                        if accept_content_len:
-                            ctx.content_len = content_len
-                            ctx.data_len = min(content_len, req_end or content_len) - (req_start or 0)
-                            return
+                            or content_len < range_end):
+                        ctx.content_len = content_len
+                        if content_len or req_end:
+                            ctx.data_len = min(content_len or req_end, req_end or content_len) - (req_start or 0)
+                        return
                     # Content-Range is either not present or invalid. Assuming remote webserver is
                     # trying to send the whole file, resume is not possible, so wiping the local file
                     # and performing entire redownload
@@ -154,7 +154,7 @@ class HttpFD(FileDownloader):
                     ctx.resume_len = 0
                     ctx.open_mode = 'wb'
                 ctx.data_len = ctx.content_len = int_or_none(ctx.data.info().get('Content-length', None))
-            except (compat_urllib_error.HTTPError, ) as err:
+            except urllib.error.HTTPError as err:
                 if err.code == 416:
                     # Unable to resume (requested range not satisfiable)
                     try:
@@ -162,7 +162,7 @@ class HttpFD(FileDownloader):
                         ctx.data = self.ydl.urlopen(
                             sanitized_Request(url, request_data, headers))
                         content_length = ctx.data.info()['Content-Length']
-                    except (compat_urllib_error.HTTPError, ) as err:
+                    except urllib.error.HTTPError as err:
                         if err.code < 500 or err.code >= 600:
                             raise
                     else:
@@ -195,7 +195,7 @@ class HttpFD(FileDownloader):
                     # Unexpected HTTP error
                     raise
                 raise RetryDownload(err)
-            except compat_urllib_error.URLError as err:
+            except urllib.error.URLError as err:
                 if isinstance(err.reason, ssl.CertificateError):
                     raise
                 raise RetryDownload(err)
@@ -204,6 +204,12 @@ class HttpFD(FileDownloader):
             except RESPONSE_READ_EXCEPTIONS as err:
                 raise RetryDownload(err)
 
+        def close_stream():
+            if ctx.stream is not None:
+                if not ctx.tmpfilename == '-':
+                    ctx.stream.close()
+                ctx.stream = None
+
         def download():
             data_len = ctx.data.info().get('Content-length', None)
 
@@ -220,10 +226,12 @@ class HttpFD(FileDownloader):
                 min_data_len = self.params.get('min_filesize')
                 max_data_len = self.params.get('max_filesize')
                 if min_data_len is not None and data_len < min_data_len:
-                    self.to_screen('\r[download] File is smaller than min-filesize (%s bytes < %s bytes). Aborting.' % (data_len, min_data_len))
+                    self.to_screen(
+                        f'\r[download] File is smaller than min-filesize ({data_len} bytes < {min_data_len} bytes). Aborting.')
                     return False
                 if max_data_len is not None and data_len > max_data_len:
-                    self.to_screen('\r[download] File is larger than max-filesize (%s bytes > %s bytes). Aborting.' % (data_len, max_data_len))
+                    self.to_screen(
+                        f'\r[download] File is larger than max-filesize ({data_len} bytes > {max_data_len} bytes). Aborting.')
                     return False
 
             byte_counter = 0 + ctx.resume_len
@@ -235,12 +243,9 @@ class HttpFD(FileDownloader):
             before = start  # start measuring
 
             def retry(e):
-                to_stdout = ctx.tmpfilename == '-'
-                if ctx.stream is not None:
-                    if not to_stdout:
-                        ctx.stream.close()
-                    ctx.stream = None
-                ctx.resume_len = byte_counter if to_stdout else os.path.getsize(encodeFilename(ctx.tmpfilename))
+                close_stream()
+                ctx.resume_len = (byte_counter if ctx.tmpfilename == '-'
+                                  else os.path.getsize(encodeFilename(ctx.tmpfilename)))
                 raise RetryDownload(e)
 
             while True:
@@ -264,19 +269,19 @@ class HttpFD(FileDownloader):
                         assert ctx.stream is not None
                         ctx.filename = self.undo_temp_name(ctx.tmpfilename)
                         self.report_destination(ctx.filename)
-                    except (OSError, IOError) as err:
+                    except OSError as err:
                         self.report_error('unable to open for writing: %s' % str(err))
                         return False
 
                     if self.params.get('xattr_set_filesize', False) and data_len is not None:
                         try:
-                            write_xattr(ctx.tmpfilename, 'user.ytdl.filesize', str(data_len).encode('utf-8'))
+                            write_xattr(ctx.tmpfilename, 'user.ytdl.filesize', str(data_len).encode())
                         except (XAttrUnavailableError, XAttrMetadataError) as err:
                             self.report_error('unable to set filesize xattr: %s' % str(err))
 
                 try:
                     ctx.stream.write(data_block)
-                except (IOError, OSError) as err:
+                except OSError as err:
                     self.to_stderr('\n')
                     self.report_error('unable to write data: %s' % str(err))
                     return False
@@ -342,9 +347,7 @@ class HttpFD(FileDownloader):
 
             if data_len is not None and byte_counter != data_len:
                 err = ContentTooShortError(byte_counter, int(data_len))
-                if count <= retries:
-                    retry(err)
-                raise err
+                retry(err)
 
             self.try_rename(ctx.tmpfilename, ctx.filename)
 
@@ -363,21 +366,20 @@ class HttpFD(FileDownloader):
 
             return True
 
-        while count <= retries:
+        for retry in RetryManager(self.params.get('retries'), self.report_retry):
             try:
                 establish_connection()
                 return download()
-            except RetryDownload as e:
-                count += 1
-                if count <= retries:
-                    self.report_retry(e.source_error, count, retries)
-                else:
-                    self.to_screen(f'[download] Got server HTTP error: {e.source_error}')
+            except RetryDownload as err:
+                retry.error = err.source_error
                 continue
             except NextFragment:
+                retry.error = None
+                retry.attempt -= 1
                 continue
             except SucceedDownload:
                 return True
-
-        self.report_error('giving up after %s retries' % retries)
+            except:  # noqa: E722
+                close_stream()
+                raise
         return False
diff --git a/hypervideo_dl/downloader/ism.py b/hypervideo_dl/downloader/ism.py
index 4d5618c..a157a8a 100644
--- a/hypervideo_dl/downloader/ism.py
+++ b/hypervideo_dl/downloader/ism.py
@@ -1,27 +1,23 @@
-from __future__ import unicode_literals
-
-import time
 import binascii
 import io
+import struct
+import time
+import urllib.error
 
 from .fragment import FragmentFD
-from ..compat import (
-    compat_Struct,
-    compat_urllib_error,
-)
+from ..utils import RetryManager
 
+u8 = struct.Struct('>B')
+u88 = struct.Struct('>Bx')
+u16 = struct.Struct('>H')
+u1616 = struct.Struct('>Hxx')
+u32 = struct.Struct('>I')
+u64 = struct.Struct('>Q')
 
-u8 = compat_Struct('>B')
-u88 = compat_Struct('>Bx')
-u16 = compat_Struct('>H')
-u1616 = compat_Struct('>Hxx')
-u32 = compat_Struct('>I')
-u64 = compat_Struct('>Q')
-
-s88 = compat_Struct('>bx')
-s16 = compat_Struct('>h')
-s1616 = compat_Struct('>hxx')
-s32 = compat_Struct('>i')
+s88 = struct.Struct('>bx')
+s16 = struct.Struct('>h')
+s1616 = struct.Struct('>hxx')
+s32 = struct.Struct('>i')
 
 unity_matrix = (s32.pack(0x10000) + s32.pack(0) * 3) * 2 + s32.pack(0x40000000)
 
@@ -142,6 +138,8 @@ def write_piff_header(stream, params):
 
         if fourcc == 'AACL':
             sample_entry_box = box(b'mp4a', sample_entry_payload)
+        if fourcc == 'EC-3':
+            sample_entry_box = box(b'ec-3', sample_entry_payload)
     elif stream_type == 'video':
         sample_entry_payload += u16.pack(0)  # pre defined
         sample_entry_payload += u16.pack(0)  # reserved
@@ -156,7 +154,7 @@ def write_piff_header(stream, params):
         sample_entry_payload += u16.pack(0x18)  # depth
         sample_entry_payload += s16.pack(-1)  # pre defined
 
-        codec_private_data = binascii.unhexlify(params['codec_private_data'].encode('utf-8'))
+        codec_private_data = binascii.unhexlify(params['codec_private_data'].encode())
         if fourcc in ('H264', 'AVC1'):
             sps, pps = codec_private_data.split(u32.pack(1))[1:]
             avcc_payload = u8.pack(1)  # configuration version
@@ -235,8 +233,6 @@ class IsmFD(FragmentFD):
     Download segments in a ISM manifest
     """
 
-    FD_NAME = 'ism'
-
     def real_download(self, filename, info_dict):
         segments = info_dict['fragments'][:1] if self.params.get(
             'test', False) else info_dict['fragments']
@@ -252,7 +248,6 @@ class IsmFD(FragmentFD):
             'ism_track_written': False,
         })
 
-        fragment_retries = self.params.get('fragment_retries', 0)
         skip_unavailable_fragments = self.params.get('skip_unavailable_fragments', True)
 
         frag_index = 0
@@ -260,8 +255,10 @@ class IsmFD(FragmentFD):
             frag_index += 1
             if frag_index <= ctx['fragment_index']:
                 continue
-            count = 0
-            while count <= fragment_retries:
+
+            retry_manager = RetryManager(self.params.get('fragment_retries'), self.report_retry,
+                                         frag_index=frag_index, fatal=not skip_unavailable_fragments)
+            for retry in retry_manager:
                 try:
                     success = self._download_fragment(ctx, segment['url'], info_dict)
                     if not success:
@@ -274,18 +271,13 @@ class IsmFD(FragmentFD):
                         write_piff_header(ctx['dest_stream'], info_dict['_download_params'])
                         extra_state['ism_track_written'] = True
                     self._append_fragment(ctx, frag_content)
-                    break
-                except compat_urllib_error.HTTPError as err:
-                    count += 1
-                    if count <= fragment_retries:
-                        self.report_retry_fragment(err, frag_index, count, fragment_retries)
-            if count > fragment_retries:
-                if skip_unavailable_fragments:
-                    self.report_skip_fragment(frag_index)
+                except urllib.error.HTTPError as err:
+                    retry.error = err
                     continue
-                self.report_error('giving up after %s fragment retries' % fragment_retries)
-                return False
 
-        self._finish_frag_download(ctx, info_dict)
+            if retry_manager.error:
+                if not skip_unavailable_fragments:
+                    return False
+                self.report_skip_fragment(frag_index)
 
-        return True
+        return self._finish_frag_download(ctx, info_dict)
diff --git a/hypervideo_dl/downloader/mhtml.py b/hypervideo_dl/downloader/mhtml.py
index c8332c0..170a78d 100644
--- a/hypervideo_dl/downloader/mhtml.py
+++ b/hypervideo_dl/downloader/mhtml.py
@@ -1,24 +1,15 @@
-# coding: utf-8
-from __future__ import unicode_literals
-
 import io
 import quopri
 import re
 import uuid
 
 from .fragment import FragmentFD
-from ..utils import (
-    escapeHTML,
-    formatSeconds,
-    srt_subtitles_timecode,
-    urljoin,
-)
+from ..compat import imghdr
+from ..utils import escapeHTML, formatSeconds, srt_subtitles_timecode, urljoin
 from ..version import __version__ as YT_DLP_VERSION
 
 
 class MhtmlFD(FragmentFD):
-    FD_NAME = 'mhtml'
-
     _STYLESHEET = """\
 html, body {
     margin: 0;
@@ -62,7 +53,7 @@ body > figure > img {
     def _escape_mime(s):
         return '=?utf-8?Q?' + (b''.join(
             bytes((b,)) if b >= 0x20 else b'=%02X' % b
-            for b in quopri.encodestring(s.encode('utf-8'), header=True)
+            for b in quopri.encodestring(s.encode(), header=True)
         )).decode('us-ascii') + '?='
 
     def _gen_cid(self, i, fragment, frag_boundary):
@@ -159,7 +150,7 @@ body > figure > img {
                 length=len(stub),
                 title=self._escape_mime(title),
                 stub=stub
-            ).encode('utf-8'))
+            ).encode())
             extra_state['header_written'] = True
 
         for i, fragment in enumerate(fragments):
@@ -176,21 +167,13 @@ body > figure > img {
                 continue
             frag_content = self._read_fragment(ctx)
 
-            mime_type = b'image/jpeg'
-            if frag_content.startswith(b'\x89PNG\r\n\x1a\n'):
-                mime_type = b'image/png'
-            if frag_content.startswith((b'GIF87a', b'GIF89a')):
-                mime_type = b'image/gif'
-            if frag_content.startswith(b'RIFF') and frag_content[8:12] == 'WEBP':
-                mime_type = b'image/webp'
-
             frag_header = io.BytesIO()
             frag_header.write(
                 b'--%b\r\n' % frag_boundary.encode('us-ascii'))
             frag_header.write(
                 b'Content-ID: <%b>\r\n' % self._gen_cid(i, fragment, frag_boundary).encode('us-ascii'))
             frag_header.write(
-                b'Content-type: %b\r\n' % mime_type)
+                b'Content-type: %b\r\n' % f'image/{imghdr.what(h=frag_content) or "jpeg"}'.encode())
             frag_header.write(
                 b'Content-length: %u\r\n' % len(frag_content))
             frag_header.write(
@@ -203,5 +186,4 @@ body > figure > img {
 
         ctx['dest_stream'].write(
             b'--%b--\r\n\r\n' % frag_boundary.encode('us-ascii'))
-        self._finish_frag_download(ctx, info_dict)
-        return True
+        return self._finish_frag_download(ctx, info_dict)
diff --git a/hypervideo_dl/downloader/niconico.py b/hypervideo_dl/downloader/niconico.py
index 521dfec..77ed39e 100644
--- a/hypervideo_dl/downloader/niconico.py
+++ b/hypervideo_dl/downloader/niconico.py
@@ -1,22 +1,17 @@
-# coding: utf-8
-from __future__ import unicode_literals
-
 import threading
 
+from . import get_suitable_downloader
 from .common import FileDownloader
-from ..downloader import get_suitable_downloader
-from ..extractor.niconico import NiconicoIE
 from ..utils import sanitized_Request
 
 
 class NiconicoDmcFD(FileDownloader):
     """ Downloading niconico douga from DMC with heartbeat """
 
-    FD_NAME = 'niconico_dmc'
-
     def real_download(self, filename, info_dict):
-        self.to_screen('[%s] Downloading from DMC' % self.FD_NAME)
+        from ..extractor.niconico import NiconicoIE
 
+        self.to_screen('[%s] Downloading from DMC' % self.FD_NAME)
         ie = NiconicoIE(self.ydl)
         info_dict, heartbeat_info_dict = ie._get_heartbeat_info(info_dict)
 
@@ -54,4 +49,4 @@ class NiconicoDmcFD(FileDownloader):
                 with heartbeat_lock:
                     timer[0].cancel()
                     download_complete = True
-            return success
+        return success
diff --git a/hypervideo_dl/downloader/rtmp.py b/hypervideo_dl/downloader/rtmp.py
index 90f1acf..0e09525 100644
--- a/hypervideo_dl/downloader/rtmp.py
+++ b/hypervideo_dl/downloader/rtmp.py
@@ -1,18 +1,15 @@
-from __future__ import unicode_literals
-
 import os
 import re
 import subprocess
 import time
 
 from .common import FileDownloader
-from ..compat import compat_str
 from ..utils import (
+    Popen,
     check_executable,
-    encodeFilename,
     encodeArgument,
+    encodeFilename,
     get_exe_version,
-    Popen,
 )
 
 
@@ -94,8 +91,7 @@ class RtmpFD(FileDownloader):
                     self.to_screen('')
                 return proc.wait()
             except BaseException:  # Including KeyboardInterrupt
-                proc.kill()
-                proc.wait()
+                proc.kill(timeout=None)
                 raise
 
         url = info_dict['url']
@@ -146,7 +142,7 @@ class RtmpFD(FileDownloader):
         if isinstance(conn, list):
             for entry in conn:
                 basic_args += ['--conn', entry]
-        elif isinstance(conn, compat_str):
+        elif isinstance(conn, str):
             basic_args += ['--conn', conn]
         if protocol is not None:
             basic_args += ['--protocol', protocol]
diff --git a/hypervideo_dl/downloader/rtsp.py b/hypervideo_dl/downloader/rtsp.py
index 7815d59..e89269f 100644
--- a/hypervideo_dl/downloader/rtsp.py
+++ b/hypervideo_dl/downloader/rtsp.py
@@ -1,13 +1,8 @@
-from __future__ import unicode_literals
-
 import os
 import subprocess
 
 from .common import FileDownloader
-from ..utils import (
-    check_executable,
-    encodeFilename,
-)
+from ..utils import check_executable, encodeFilename
 
 
 class RtspFD(FileDownloader):
@@ -32,7 +27,7 @@ class RtspFD(FileDownloader):
         retval = subprocess.call(args)
         if retval == 0:
             fsize = os.path.getsize(encodeFilename(tmpfilename))
-            self.to_screen('\r[%s] %s bytes' % (args[0], fsize))
+            self.to_screen(f'\r[{args[0]}] {fsize} bytes')
             self.try_rename(tmpfilename, filename)
             self._hook_progress({
                 'downloaded_bytes': fsize,
diff --git a/hypervideo_dl/downloader/websocket.py b/hypervideo_dl/downloader/websocket.py
index 58e2bce..6837ff1 100644
--- a/hypervideo_dl/downloader/websocket.py
+++ b/hypervideo_dl/downloader/websocket.py
@@ -1,19 +1,12 @@
+import asyncio
+import contextlib
 import os
 import signal
-import asyncio
 import threading
 
-try:
-    import websockets
-except (ImportError, SyntaxError):
-    # websockets 3.10 on python 3.6 causes SyntaxError
-    # See https://github.com/hypervideo/hypervideo/issues/2633
-    has_websockets = False
-else:
-    has_websockets = True
-
 from .common import FileDownloader
 from .external import FFmpegFD
+from ..dependencies import websockets
 
 
 class FFmpegSinkFD(FileDownloader):
@@ -26,14 +19,12 @@ class FFmpegSinkFD(FileDownloader):
         async def call_conn(proc, stdin):
             try:
                 await self.real_connection(stdin, info_dict)
-            except (BrokenPipeError, OSError):
+            except OSError:
                 pass
             finally:
-                try:
+                with contextlib.suppress(OSError):
                     stdin.flush()
                     stdin.close()
-                except OSError:
-                    pass
                 os.kill(os.getpid(), signal.SIGINT)
 
         class FFmpegStdinFD(FFmpegFD):
diff --git a/hypervideo_dl/downloader/youtube_live_chat.py b/hypervideo_dl/downloader/youtube_live_chat.py
index dd21ac8..dfd290a 100644
--- a/hypervideo_dl/downloader/youtube_live_chat.py
+++ b/hypervideo_dl/downloader/youtube_live_chat.py
@@ -1,24 +1,20 @@
-from __future__ import division, unicode_literals
-
 import json
 import time
+import urllib.error
 
 from .fragment import FragmentFD
-from ..compat import compat_urllib_error
 from ..utils import (
-    try_get,
+    RegexNotFoundError,
+    RetryManager,
     dict_get,
     int_or_none,
-    RegexNotFoundError,
+    try_get,
 )
-from ..extractor.youtube import YoutubeBaseInfoExtractor as YT_BaseIE
 
 
 class YoutubeLiveChatFD(FragmentFD):
     """ Downloads YouTube live chats fragment by fragment """
 
-    FD_NAME = 'youtube_live_chat'
-
     def real_download(self, filename, info_dict):
         video_id = info_dict['video_id']
         self.to_screen('[%s] Downloading live chat' % self.FD_NAME)
@@ -26,7 +22,6 @@ class YoutubeLiveChatFD(FragmentFD):
             self.report_warning('Live chat download runs until the livestream ends. '
                                 'If you wish to download the video simultaneously, run a separate hypervideo instance')
 
-        fragment_retries = self.params.get('fragment_retries', 0)
         test = self.params.get('test', False)
 
         ctx = {
@@ -35,7 +30,9 @@ class YoutubeLiveChatFD(FragmentFD):
             'total_frags': None,
         }
 
-        ie = YT_BaseIE(self.ydl)
+        from ..extractor.youtube import YoutubeBaseInfoExtractor
+
+        ie = YoutubeBaseInfoExtractor(self.ydl)
 
         start_time = int(time.time() * 1000)
 
@@ -54,7 +51,7 @@ class YoutubeLiveChatFD(FragmentFD):
                     replay_chat_item_action = action['replayChatItemAction']
                     offset = int(replay_chat_item_action['videoOffsetTimeMsec'])
                 processed_fragment.extend(
-                    json.dumps(action, ensure_ascii=False).encode('utf-8') + b'\n')
+                    json.dumps(action, ensure_ascii=False).encode() + b'\n')
             if offset is not None:
                 continuation = try_get(
                     live_chat_continuation,
@@ -96,7 +93,7 @@ class YoutubeLiveChatFD(FragmentFD):
                     'isLive': True,
                 }
                 processed_fragment.extend(
-                    json.dumps(pseudo_action, ensure_ascii=False).encode('utf-8') + b'\n')
+                    json.dumps(pseudo_action, ensure_ascii=False).encode() + b'\n')
             continuation_data_getters = [
                 lambda x: x['continuations'][0]['invalidationContinuationData'],
                 lambda x: x['continuations'][0]['timedContinuationData'],
@@ -112,8 +109,7 @@ class YoutubeLiveChatFD(FragmentFD):
             return continuation_id, live_offset, click_tracking_params
 
         def download_and_parse_fragment(url, frag_index, request_data=None, headers=None):
-            count = 0
-            while count <= fragment_retries:
+            for retry in RetryManager(self.params.get('fragment_retries'), self.report_retry, frag_index=frag_index):
                 try:
                     success = dl_fragment(url, request_data, headers)
                     if not success:
@@ -128,21 +124,15 @@ class YoutubeLiveChatFD(FragmentFD):
                     live_chat_continuation = try_get(
                         data,
                         lambda x: x['continuationContents']['liveChatContinuation'], dict) or {}
-                    if info_dict['protocol'] == 'youtube_live_chat_replay':
-                        if frag_index == 1:
-                            continuation_id, offset, click_tracking_params = try_refresh_replay_beginning(live_chat_continuation)
-                        else:
-                            continuation_id, offset, click_tracking_params = parse_actions_replay(live_chat_continuation)
-                    elif info_dict['protocol'] == 'youtube_live_chat':
-                        continuation_id, offset, click_tracking_params = parse_actions_live(live_chat_continuation)
-                    return True, continuation_id, offset, click_tracking_params
-                except compat_urllib_error.HTTPError as err:
-                    count += 1
-                    if count <= fragment_retries:
-                        self.report_retry_fragment(err, frag_index, count, fragment_retries)
-            if count > fragment_retries:
-                self.report_error('giving up after %s fragment retries' % fragment_retries)
-                return False, None, None, None
+
+                    func = (info_dict['protocol'] == 'youtube_live_chat' and parse_actions_live
+                            or frag_index == 1 and try_refresh_replay_beginning
+                            or parse_actions_replay)
+                    return (True, *func(live_chat_continuation))
+                except urllib.error.HTTPError as err:
+                    retry.error = err
+                    continue
+            return False, None, None, None
 
         self._prepare_and_start_frag_download(ctx, info_dict)
 
@@ -190,7 +180,7 @@ class YoutubeLiveChatFD(FragmentFD):
                     request_data['context']['clickTracking'] = {'clickTrackingParams': click_tracking_params}
                 headers = ie.generate_api_headers(ytcfg=ytcfg, visitor_data=visitor_data)
                 headers.update({'content-type': 'application/json'})
-                fragment_request_data = json.dumps(request_data, ensure_ascii=False).encode('utf-8') + b'\n'
+                fragment_request_data = json.dumps(request_data, ensure_ascii=False).encode() + b'\n'
                 success, continuation_id, offset, click_tracking_params = download_and_parse_fragment(
                     url, frag_index, fragment_request_data, headers)
             else:
@@ -201,8 +191,7 @@ class YoutubeLiveChatFD(FragmentFD):
             if test:
                 break
 
-        self._finish_frag_download(ctx, info_dict)
-        return True
+        return self._finish_frag_download(ctx, info_dict)
 
     @staticmethod
     def parse_live_timestamp(action):