[FFmpeg-devel] [PATCH] avcodec: Add AVClass to AVCodecParameters

Michael Niedermayer michael at niedermayer.cc
Tue May 10 16:22:59 CEST 2016

On Tue, May 10, 2016 at 03:56:18PM +0200, Hendrik Leppkes wrote:
> On Tue, May 10, 2016 at 2:10 PM, Michael Niedermayer
> <michael at niedermayer.cc> wrote:
> >
> > libavformat gathers information about streams in av_find_stream_info()
> > and that is all information completely unneeded by decoders
> > no decoder needs the width and height from the parser run by
> > av_find_stream_info() or other fields. These are only needed when they
> > come from format headers.
> > The only reason to go to the troubble to set these fields (and thats
> > quite some troubble) is to provide this information to the user
> > application and thus user
> >
> >
> Technically the decoders wouldn't need this information, that is correct.
> However, many applications do on a technical level. ffmpeg.c for
> example would die a horrible death if it wouldn't know the resolution
> of the video beforehand, because its setup requires this crucial
> information before initializing filters and output encoders.
> One could write an application to respond to such data on the fly, but
> alas many apps at least want an initial value, or can't even respond
> to dynamic changes at all.
> Having this information available to the user to choose streams from
> is nice, but not the only reason.

so we agree, good

the disagreement seems thus only about adding AVClass
which is something we can do now, but after the next release we will
not be able to do it for a long time (as it would break released ABI)

Is there consensus (iam happy to abstain if theres otherwise consensus)
AVClass should not be added to AVCodecParameters ? if so that should
be documented

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Into a blind darkness they enter who follow after the Ignorance,
they as if into a greater darkness enter who devote themselves
to the Knowledge alone. -- Isha Upanishad
-------------- 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/20160510/ef885069/attachment.sig>

More information about the ffmpeg-devel mailing list