Re: [Libquicktime-devel] More patches

[Burkhard P. <pl...@ip...>]

Hi,

Am 21.11.2012 13:50, schrieb Joseph Artsimovich:
> 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?

For everything which supports variable framerates.

> 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.

I think for DV it's the same. This would mean that at least dnxhd, DV and MPEG-2
are constant frame rate while most others might be more flexible.

Burkhard