Improve `--download-sections`

* Support negative time-ranges
* Add `*from-url` to obey time-ranges in URL

Closes #7248

1 files changed, 18 insertions, 4 deletions

diff --git a/yt_dlp/utils/_utils.py b/yt_dlp/utils/_utils.py
index bc1bc9116..56acadd73 100644
--- a/yt_dlp/utils/_utils.py
+++ b/yt_dlp/utils/_utils.py
@@ -3753,11 +3753,11 @@ def match_filter_func(filters, breaking_filters=None):
 
 
 class download_range_func:
-    def __init__(self, chapters, ranges):
-        self.chapters, self.ranges = chapters, ranges
+    def __init__(self, chapters, ranges, from_info=False):
+        self.chapters, self.ranges, self.from_info = chapters, ranges, from_info
 
     def __call__(self, info_dict, ydl):
-        if not self.ranges and not self.chapters:
+        if not any((self.ranges, self.chapters, self.from_info)):
             yield {}
 
         warning = ('There are no chapters matching the regex' if info_dict.get('chapters')
@@ -3770,7 +3770,21 @@ class download_range_func:
         if self.chapters and warning:
             ydl.to_screen(f'[info] {info_dict["id"]}: {warning}')
 
-        yield from ({'start_time': start, 'end_time': end} for start, end in self.ranges or [])
+        for start, end in self.ranges or []:
+            yield {
+                'start_time': self._handle_negative_timestamp(start, info_dict),
+                'end_time': self._handle_negative_timestamp(end, info_dict),
+            }
+
+        if self.from_info and (info_dict.get('start_time') or info_dict.get('end_time')):
+            yield {
+                'start_time': info_dict.get('start_time'),
+                'end_time': info_dict.get('end_time'),
+            }
+
+    @staticmethod
+    def _handle_negative_timestamp(time, info):
+        return max(info['duration'] + time, 0) if info.get('duration') and time < 0 else time
 
     def __eq__(self, other):
         return (isinstance(other, download_range_func)