Re: [Libquicktime-devel] More patches

[Joseph A. <jo...@mi...>]

On 21/11/2012 10:18, Burkhard Plaum wrote:
> ...
>
>
> I would make it depend on the codec_id because it also applied to IMX.
> For CODEC_ID_MPEG2VIDEO (and probably others) set time_base to the framerate
> like you did earlier, and increase PTS by one for each frame.
>
> Just found this snippet in my other libavcodec frontend:
>
> static void set_framerate(ffmpeg_video_stream_t * st)
>     {
>     if(st->format.framerate_mode == GAVL_FRAMERATE_CONSTANT)
>       {
>       st->stream->codec->time_base.den = st->format.timescale;
>       st->stream->codec->time_base.num = st->format.frame_duration;
>       }
>     else
>       {
>       st->stream->codec->time_base.den = st->format.timescale;
>       st->stream->codec->time_base.num = 1;
>       }
>     }
Are you proposing making time_base.num = 1 for everything but 
CODEC_ID_MPEG2VIDEO? I think that would cause problems with other 
codecs. For instance, ffmpeg's dnxhd encoder chooses encoding profile by 
matching bitrate, frame rate and frame size.
What I was proposing is introducing a pts divisor/multiplier that will 
be 1 except for XDCAM, where it will be equal to time scale.

-- 
Joseph Artsimovich
Senior C++ Applications Developer
MirriAd Ltd