[FFmpeg-devel] ffmpeg latest git - rewrapping (codec copy) breaks container fps/tbr values

[David Favor]

Michael Niedermayer wrote:
> On Mon, Apr 13, 2015 at 04:36:18PM -0500, David Favor wrote:
>> David Favor wrote:
>>> David Favor wrote:
>>>> The following command:
>>>>
>>>>    ffmpeg -i clip.mts -c:v copy -c:a copy clip.mp4 (or clip.mov)
>>>>
>>>> seems to incorrectly write container values for fps + tbr which
>>>> causes .mp4/.mov files to play with very odd jerky movements.
>>> https://trac.ffmpeg.org/ticket/974 seems to be a ticket already
>>> opened for this.
>> More jittery artifacts.
>>
>> This produces no jitter:
>>
>>      ffmpeg -fflags +genpts -i clip.mts -c:v copy -c:a copy clip.mp4
>>
> 
>> This produces jitter:
>>
>>      ffmpeg -fflags +genpts -i clip.mts -c:v copy -c:a libfaac clip.mp4
>>
>> Anytime the audio stream is transcoded (libfaac or fdk), jitter returns.
>>
>> This behavior isn't mentioned in the above ticket.
> 
> if you found a bug which isnt reported yet (i dont know if that applies
> here) please open a new seperate ticket

https://trac.ffmpeg.org/ticket/4485 opened to cover audio transcode
having any effect on video stream.

https://trac.ffmpeg.org/ticket/974 updated with additional info about
-fflags +genpts having unexpected effect on container fps + tbr values.
Specifically, -fflags +genpts seems to imply the target footage will
have same fps + tbr values as source footage.