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

[Ronald S. Bultje]

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.

Ronald