[FFmpeg-devel] [PATCH 0/2] avformat movenc add flag to allow disabling limit on timescale

[Gyan Doshi]

On 05-05-2020 03:16 am, vectronic wrote:
>
>> On 4 May 2020, at 17:56, Gyan Doshi <ffmpeg at gyani.pro> wrote:
>>
>>
>>
>> On 04-05-2020 09:54 pm, vectronic wrote:
>>> I needed to encode to mov/mp4 with a timebase of 1/600 and the output was not as expected.
>> What was the unexpected output?
>>
>> You can use video_track_timescale to set any custom scale.
>>
>> Gyan
> The unexpected output is that if you request a timebase of 600 as an argument for ffmpeg on the command line, the output timebase is forced to be greater than 10000.
>
> As far as I can see there is no documentation or message logged that the following logic is applied which means the output differs to what a user has requested and expects:
>
> while(track->timescale < 10000)
>      track->timescale *= 2;
>
> I believe video_track_timescale applies to all tracks - so you unable to specify timescales per track?

I believe your flag also disables the scale clamping for all video 
tracks. In that case, better to extend the min value of 
video_track_timescale  to -1 to implement this instead of a new flag.

Gyan