[FFmpeg-trac] #8682(undetermined:new): Feature: optionally write new headers while copying streams
FFmpeg
trac at avcodec.org
Wed May 27 21:57:57 EEST 2020
#8682: Feature: optionally write new headers while copying streams
-------------------------------------+-------------------------------------
Reporter: TiredEyes | Owner:
Type: enhancement | Status: new
Priority: wish | Component:
| undetermined
Version: unspecified | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by TiredEyes):
I have prepared an example video for demonstrating the issue, but it's
very big: 522 MB.
The reason is it needs a certain length in order to show the problem. I've
also tried to cut out a shorter version, but you can not reproduce issue
with that.
'''Description of the issue:'''
When you play it straight from start to end, all players I've tested (VLC,
mpv) work fine. Problems begin when you try to skip or singlestep
backward. E.g. in mpv, you can singlestep backward using the {{{,}}} key,
but only a few steps, then you get this error:
{{{
[ffmpeg/audio] mp2: Header missing
Error decoding audio.
}}}
and you can not step backward further. The same message pops up when you
skip backwoards using the cursor {{{left}}} or {{{down}}} keys. Both
situations do not happen always. In my example, you need to go forward
several minutes, then skip backward a few times. And the singlestepping
problem did not occur at all this video.
When I transcode the audio to pcm_dvd using
{{{ffmpeg -i test_recording_BROKEN.mpg -c:v copy -c:a pcm_dvd
test_recording_TRANSCODED.mpg}}}
then mpv can play the video and singlestep or skip forward and backward as
much as I want. But this has 2 downsides: the file gets bigger and I would
like to avoid transcoding.
If there is a way how I can upload this big file please let me know.
Otherwise, this is how it was produced:
Recorded from TV using the VDR (Video Disk Recorder) software in SD. VDR
writes it to disk as mpeg2 transport stream {{{.ts}}}. Then I
demultiplexed it using ProjectX, because it can select a range to
demultiplex in a convenient way. Finally multiplexed into .mpg using
{{{mplex -f 3 -o test_recording_BROKEN.mpg test_recording.m2v
test_recording.m2a}}}
If you have the same toolchain available, you could produce a test video
on your own. My test video was recorded from german TV station "Das Erste"
a.k.a. ARD. The frequentness of the issue seems to be different depending
on the TV station it was recorded from, and generally more frequent in
older recordings.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/8682#comment:2>
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