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

Michael Niedermayer michael at niedermayer.cc
Tue May 10 14:10:50 CEST 2016


On Tue, May 10, 2016 at 08:24:35AM +0200, Hendrik Leppkes wrote:
> On Tue, May 10, 2016 at 2:07 AM, Michael Niedermayer
> <michael at niedermayer.cc> wrote:
> > Allow enumeration, read and write of fields without requiring #if on versions
> > All other public structures can be accessed through AVOptions
> >
> > TODO: add all fields to AVOption table
> > TODO: bump version
> > TODO: update APIChanges
> 
> 
> I don't like this, the struct is pretty cleanly defined and unlikely
> to be extended much over time.
> Most other structs have AVOptions so the CLI can interact with it, but

> this struct is not meant to be modified by users, its just a direct
> line of communication between demuxer->decoder or encoder->muxer.

that doesnt match the actual use in the code
the code does also use it as you describe but its not "just" that way
it also uses it to export information to the user.

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

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

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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