[FFmpeg-devel] [WIP] Seek / subfile support in concat demuxer

Michael Niedermayer michaelni at gmx.at
Sun Feb 23 01:55:34 CET 2014

On Fri, Feb 21, 2014 at 08:50:12PM +0100, Nicolas George wrote:
> This patch series is work in progress to implement the "seek" option in the
> concat demuxer, that allows extracting a part of the file, with exact
> accuracy.
> It could serve as a base to implement EDL support for formats that require
> then.
> For video, it defines a new packet flag that informs libavcodec to decode
> the frame (it may serve as reference frame for a frame we want) but not
> return it to the user.
> For audio, it uses the SKIP_SAMPLES side data.

> Using side data for video too instead of a flag would also be an option, I
> have no strong opinion about it.

i neither have a strong oppinon but side data would be more consistent
also side data would allow conveyng the information earlier
that is a keyframe could already contain the exact duration covering
multiple frames that should be discarded
and in theory side data would allow cutting a frame in half
if for example in case of a slide show frames sra displayed for
significat time (iam not suggesting to implement this ATM though)

> For now, it works with threads disabled, but I get some strange
> thread-related decoding errors, see trac ticket #3406.
> [PATCH 1/6] lavc/pthread: copy packet side data.
> [PATCH 2/6] lavu: add pkt_flags field to AVFrame.
> [PATCH 3/6] lavc: add AV_PKT_FLAG_DISCARD.
> [PATCH 4/6] lavu/frame: add AV_FRAME_DATA_SKIP_SAMPLES.
> [PATCH 5/6] lavc/utils: bind SKIP_SAMPLES to the frame.
> [PATCH 6/6] concat: support seeking inside sub-files [WIP].
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In fact, the RIAA has been known to suggest that students drop out
of college or go to community college in order to be able to afford
settlements. -- The RIAA
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20140223/85c813d9/attachment.asc>

More information about the ffmpeg-devel mailing list