[FFmpeg-devel] [PATCH v2 4/8] ffmpeg: remove sub-frame warning

Michael Niedermayer michael at niedermayer.cc
Wed Mar 23 18:37:25 CET 2016


On Wed, Mar 23, 2016 at 06:06:37PM +0100, wm4 wrote:
> On Wed, 23 Mar 2016 17:51:11 +0100
> Michael Niedermayer <michael at niedermayer.cc> wrote:
> 
> > On Wed, Mar 23, 2016 at 02:02:11PM +0100, wm4 wrote:
> > > It's not practical to keep this with the new decode API.
> > > ---
> > >  ffmpeg.c | 7 -------
> > >  ffmpeg.h | 1 -
> > >  2 files changed, 8 deletions(-)  
> > 
> > its not practical in ffmpeg.c but libavcodec should be able to easily
> > check that a decoder which doesnt declare AV_CODEC_CAP_SUBFRAMES
> > doesnt decode "subframes"
> > Can you move this check into libavcodec ?
> > i think otherwise nothing would be checking for missing
> > AV_CODEC_CAP_SUBFRAMES anymore
> > 
> 
> What's the point of this check?

to keep track of / detect the cases that put multiple decodable frames
in a packet.

Whats the point of that?
there where several IIRC
one is that when too many frames are put in a packet 
latency increases, another is that seeking granularity is worse
(if its not even one packet for the whole file ...)
also when stream copying most muxers do expect 1 frame per packet
so that would generate invalid files

AV_CODEC_CAP_SUBFRAMES kind of says, "i know it has multiple frames
per packet and thats ok or its just nt practical to do anything about"

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Rewriting code that is poorly written but fully understood is good.
Rewriting code that one doesnt understand is a sign that one is less smart
then the original author, trying to rewrite it will not make it better.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 181 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20160323/929c04d5/attachment.sig>


More information about the ffmpeg-devel mailing list