[dash,youtube] Download live from start to end (#888)

* Add option `--live-from-start` to enable downloading live videos from start
* Add key `is_from_start` in formats to identify formats (of live videos) that downloads from start
* [dash] Create protocol `http_dash_segments_generator` that allows a function to be passed instead of fragments
* [fragment] Allow multiple live dash formats to download simultaneously
* [youtube] Implement fragment re-fetching for the live dash formats
* [youtube] Re-extract dash manifest every 5 hours (manifest expires in 6hrs)
* [postprocessor/ffmpeg] Add `FFmpegFixupDuplicateMoovPP` to fixup duplicated moov atoms

Known issue: Ctrl+C doesn't work on Windows when downloading multiple formats

Closes #1521
Authored by: nao20010128nao, pukkandan

yt_dlp/postprocessor/__init__.py

@@ -9,6 +9,7 @@ from .ffmpeg import (
     FFmpegPostProcessor,
     FFmpegEmbedSubtitlePP,
     FFmpegExtractAudioPP,
+    FFmpegFixupDuplicateMoovPP,
     FFmpegFixupDurationPP,
     FFmpegFixupStretchedPP,
     FFmpegFixupTimestampPP,

yt_dlp/postprocessor/common.py

@@ -1,6 +1,5 @@
 from __future__ import unicode_literals
 
-import copy
 import functools
 import os
 
@@ -18,7 +17,7 @@ class PostProcessorMetaClass(type):
     def run_wrapper(func):
         @functools.wraps(func)
         def run(self, info, *args, **kwargs):
-            info_copy = copy.deepcopy(self._copy_infodict(info))
+            info_copy = self._copy_infodict(info)
             self._hook_progress({'status': 'started'}, info_copy)
             ret = func(self, info, *args, **kwargs)
             if ret is not None:

yt_dlp/postprocessor/ffmpeg.py

@@ -908,13 +908,23 @@ class FFmpegFixupTimestampPP(FFmpegFixupPostProcessor):
         return [], info
 
 
-class FFmpegFixupDurationPP(FFmpegFixupPostProcessor):
+class FFmpegCopyStreamPostProcessor(FFmpegFixupPostProcessor):
+    MESSAGE = 'Copying stream'
+
     @PostProcessor._restrict_to(images=False)
     def run(self, info):
-        self._fixup('Fixing video duration', info['filepath'], ['-c', 'copy', '-map', '0', '-dn'])
+        self._fixup(self.MESSAGE, info['filepath'], ['-c', 'copy', '-map', '0', '-dn'])
         return [], info
 
 
+class FFmpegFixupDurationPP(FFmpegCopyStreamPostProcessor):
+    MESSAGE = 'Fixing video duration'
+
+
+class FFmpegFixupDuplicateMoovPP(FFmpegCopyStreamPostProcessor):
+    MESSAGE = 'Fixing duplicate MOOV atoms'
+
+
 class FFmpegSubtitlesConvertorPP(FFmpegPostProcessor):
     SUPPORTED_EXTS = ('srt', 'vtt', 'ass', 'lrc')