[FFmpeg-user] h264 timebase question
stuartrbruce at gmail.com
Wed Jan 1 21:05:23 CET 2014
On 31/12/2013 15:15, Carl Eugen Hoyos wrote:
> Stuart Bruce <stuartrbruce <at> gmail.com> writes:
>> time_base (which has become 1/12288 even though the source
>> is 1/24000),
> I believe you can set this with -video_track_timescale 24000
That's great, thank you for pointing that out. That works, and the
resulting MOV has the correct time_base and also, as a result, the same
duration_ts value as I expected.
Crucially, this seems to now mean that the thumbnail generation through
seeking now appears to be frame-accurate, when it wasn't before. I need
to test it thoroughly, but it looks like it's all sorted.
There's still one mystery, which is why the codec_time_base when
exported from Media Composer is given as 1/48000 whereas the
codec_time_base from an FFmpeg export is 1/48, but it doesn't seem to be
affecting the results I'm getting so I'm happy to let that one just be a
mystery if need be!
stuart at stuartbruce.co.uk
More information about the ffmpeg-user