[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            |

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
 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
 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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