[extractor/common, downloader/ism] Extract SSTR subtitle tracks

_parse_ism_formats was extended into _parse_ism_formats_and_subtitles;
all direct users were updated, though _extract_ism_formats was left
as a compatibility wrapper.

The SSTR downloader was also modified in order to prepare for muxing
subtitle streams, although no support for any subtitle codecs was
added in this commit.

1 files changed, 69 insertions, 36 deletions

diff --git a/yt_dlp/extractor/common.py b/yt_dlp/extractor/common.py
index 0c56a9015..045d463d6 100644
--- a/yt_dlp/extractor/common.py
+++ b/yt_dlp/extractor/common.py
@@ -2750,26 +2750,38 @@ class InfoExtractor(object):
                         else:
                             # Assuming direct URL to unfragmented media.
                             f['url'] = base_url
-                        formats.append(f)
+                        if content_type in ('video', 'audio'):
+                            formats.append(f)
+                        elif content_type == 'text':
+                            subtitles.setdefault(lang or 'und', []).append(f)
                     else:
                         self.report_warning('Unknown MIME type %s in DASH manifest' % mime_type)
         return formats, subtitles
 
-    def _extract_ism_formats(self, ism_url, video_id, ism_id=None, note=None, errnote=None, fatal=True, data=None, headers={}, query={}):
+    def _extract_ism_formats(self, *args, **kwargs):
+        fmts, subs = self._extract_ism_formats_and_subtitles(*args, **kwargs)
+        if subs:
+            self.report_warning(bug_reports_message(
+                "Ignoring subtitle tracks found in the ISM manifest; "
+                "if any subtitle tracks are missing,"
+            ))
+        return fmts
+
+    def _extract_ism_formats_and_subtitles(self, ism_url, video_id, ism_id=None, note=None, errnote=None, fatal=True, data=None, headers={}, query={}):
         res = self._download_xml_handle(
             ism_url, video_id,
             note=note or 'Downloading ISM manifest',
             errnote=errnote or 'Failed to download ISM manifest',
             fatal=fatal, data=data, headers=headers, query=query)
         if res is False:
-            return []
+            return [], {}
         ism_doc, urlh = res
         if ism_doc is None:
-            return []
+            return [], {}
 
-        return self._parse_ism_formats(ism_doc, urlh.geturl(), ism_id)
+        return self._parse_ism_formats_and_subtitles(ism_doc, urlh.geturl(), ism_id)
 
-    def _parse_ism_formats(self, ism_doc, ism_url, ism_id=None):
+    def _parse_ism_formats_and_subtitles(self, ism_doc, ism_url, ism_id=None):
         """
         Parse formats from ISM manifest.
         References:
@@ -2777,22 +2789,24 @@ class InfoExtractor(object):
             https://msdn.microsoft.com/en-us/library/ff469518.aspx
         """
         if ism_doc.get('IsLive') == 'TRUE':
-            return []
+            return [], {}
         if (not self._downloader.params.get('allow_unplayable_formats')
                 and ism_doc.find('Protection') is not None):
-            return []
+            return [], {}
 
         duration = int(ism_doc.attrib['Duration'])
         timescale = int_or_none(ism_doc.get('TimeScale')) or 10000000
 
         formats = []
+        subtitles = {}
         for stream in ism_doc.findall('StreamIndex'):
             stream_type = stream.get('Type')
-            if stream_type not in ('video', 'audio'):
+            if stream_type not in ('video', 'audio', 'text'):
                 continue
             url_pattern = stream.attrib['Url']
             stream_timescale = int_or_none(stream.get('TimeScale')) or timescale
             stream_name = stream.get('Name')
+            stream_language = stream.get('Language', 'und')
             for track in stream.findall('QualityLevel'):
                 fourcc = track.get('FourCC', 'AACL' if track.get('AudioTag') == '255' else None)
                 # TODO: add support for WVC1 and WMAP
@@ -2839,33 +2853,52 @@ class InfoExtractor(object):
                     format_id.append(stream_name)
                 format_id.append(compat_str(tbr))
 
-                formats.append({
-                    'format_id': '-'.join(format_id),
-                    'url': ism_url,
-                    'manifest_url': ism_url,
-                    'ext': 'ismv' if stream_type == 'video' else 'isma',
-                    'width': width,
-                    'height': height,
-                    'tbr': tbr,
-                    'asr': sampling_rate,
-                    'vcodec': 'none' if stream_type == 'audio' else fourcc,
-                    'acodec': 'none' if stream_type == 'video' else fourcc,
-                    'protocol': 'ism',
-                    'fragments': fragments,
-                    '_download_params': {
-                        'duration': duration,
-                        'timescale': stream_timescale,
-                        'width': width or 0,
-                        'height': height or 0,
-                        'fourcc': fourcc,
-                        'codec_private_data': track.get('CodecPrivateData'),
-                        'sampling_rate': sampling_rate,
-                        'channels': int_or_none(track.get('Channels', 2)),
-                        'bits_per_sample': int_or_none(track.get('BitsPerSample', 16)),
-                        'nal_unit_length_field': int_or_none(track.get('NALUnitLengthField', 4)),
-                    },
-                })
-        return formats
+                if stream_type == 'text':
+                    subtitles.setdefault(stream_language, []).append({
+                        'ext': 'ismt',
+                        'protocol': 'ism',
+                        'url': ism_url,
+                        'manifest_url': ism_url,
+                        'fragments': fragments,
+                        '_download_params': {
+                            'stream_type': stream_type,
+                            'duration': duration,
+                            'timescale': stream_timescale,
+                            'fourcc': fourcc,
+                            'language': stream_language,
+                            'codec_private_data': track.get('CodecPrivateData'),
+                        }
+                    })
+                elif stream_type in ('video', 'audio'):
+                    formats.append({
+                        'format_id': '-'.join(format_id),
+                        'url': ism_url,
+                        'manifest_url': ism_url,
+                        'ext': 'ismv' if stream_type == 'video' else 'isma',
+                        'width': width,
+                        'height': height,
+                        'tbr': tbr,
+                        'asr': sampling_rate,
+                        'vcodec': 'none' if stream_type == 'audio' else fourcc,
+                        'acodec': 'none' if stream_type == 'video' else fourcc,
+                        'protocol': 'ism',
+                        'fragments': fragments,
+                        '_download_params': {
+                            'stream_type': stream_type,
+                            'duration': duration,
+                            'timescale': stream_timescale,
+                            'width': width or 0,
+                            'height': height or 0,
+                            'fourcc': fourcc,
+                            'language': stream_language,
+                            'codec_private_data': track.get('CodecPrivateData'),
+                            'sampling_rate': sampling_rate,
+                            'channels': int_or_none(track.get('Channels', 2)),
+                            'bits_per_sample': int_or_none(track.get('BitsPerSample', 16)),
+                            'nal_unit_length_field': int_or_none(track.get('NALUnitLengthField', 4)),
+                        },
+                    })
+        return formats, subtitles
 
     def _parse_html5_media_entries(self, base_url, webpage, video_id, m3u8_id=None, m3u8_entry_protocol='m3u8', mpd_id=None, preference=None, quality=None):
         def absolute_url(item_url):