[FFmpeg-devel] [PATCH] avutil/frame: Remove requirements to use accessors for AVFrame

Ronald S. Bultje rsbultje at gmail.com
Mon Jan 9 17:27:09 EET 2017


Hi,

On Mon, Jan 9, 2017 at 8:48 AM, wm4 <nfxjfg at googlemail.com> wrote:

> On Mon, 9 Jan 2017 08:17:08 -0500
> "Ronald S. Bultje" <rsbultje at gmail.com> wrote:
>
> > Hi,
> >
> > On Mon, Jan 9, 2017 at 7:15 AM, wm4 <nfxjfg at googlemail.com> wrote:
> >
> > >     /**
> > >      * Not to be accessed directly from outside libavutil
> > >      */
> > >     AVBufferRef *qp_table_buf;
> > >
> > > The comment should be adjusted and allow direct access. Also,
> > > it should be moved out of the FF_API_FRAME_QP ifdef (why was
> > > it under it anyway).
> >
> >
> > I disagree. FF_API_FRAME_QP is not something that exists or is useful
> > outside a handful of codecs (basically mpeg-1/2/4). If we want this to be
> > public API, it should exist in a way that makes it useful to the majority
> > of codecs that use quantization. I'm speaking codecs not developed by
> > people that implemented qp_table_buf, for example vp3/5/6/8/9 etc.
> >
> > This also means we need a useful way to normalization the quantizer to a
> > universal scale. Exporting it as SCALE_MPEG, SCALE_H264 etc. is not
> useful.
> > We need a universal Q so -sameq has some kind of meaning when re-encoding
> > mpeg-4 to vp9. Also, aq visualization in libavfilter would suddenly be
> > meaningful across codecs. Etc.
>
> Ah, I thought the QP API survived, but now I see that the accessors are
> within FF_API_FRAME_QP as well. So this is not a bug like I thought,
> but intentional, and all QP retrieval will be removed after the API
> bump. Just strange that the accessors have no attribute_deprecated.


I agree that's strange. We should probably add them...

Ronald


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