[FFmpeg-devel] [PATCH/RFC] Update libx264.c to use new libx264 features (b_keyframe, DTS support)

Michael Niedermayer michaelni
Fri Jan 15 03:55:24 CET 2010

On Thu, Jan 14, 2010 at 06:14:19PM -0500, Jason Garrett-Glaser wrote:
> This patch updates libx264.c to support a few new features:
> 1) Keyframes are now signalled by x264_picture_t->b_keyframe.  This
> allows x264 to have non-IDR keyframes, such as in the new Periodic
> Intra Refresh feature (see http://x264dev.multimedia.cx/?p=249).
> 2) DTS are now set correctly using x264's native VFR handling system.
> 3) Timebase is now set using x264's native VFR handling system.

> Potential issues:
> 1) FPS is the same as timebase.  Is this necessarily correct?

probably not

> Ideally, for ratecontrol purposes (x264 doesn't have VFR ratecontrol
> yet, but it's getting it soon), the FPS should be the average input
> fps, but that's probably not always possible.  Is there any value we
> should use instead of timebase?

hmm, we have AVStream.avg_frame_rate but a encoder has no access to
that currently

> 2) x264's DTS values start at a negative value in the case of
> B-frames; x264 leaves it up to the muxer whether to pass through the
> negative values, fix them with an initial delay, fix them with DTS
> compression, or use an EDTS element or similar.  Will this work in
> ffmpeg, or will libx264.c have to munge the dts values somehow?

negative dts should work

no comment about the patch, iam not maintainer of it and my todo is too

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When the tyrant has disposed of foreign enemies by conquest or treaty, and
there is nothing more to fear from them, then he is always stirring up
some war or other, in order that the people may require a leader. -- Plato
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20100115/5b257e3f/attachment.pgp>

More information about the ffmpeg-devel mailing list