[FFmpeg-devel] libavc/libx264: add support to propagate SSE values through encoder stats

[Carotti, Elias]

On Fri, 2023-10-13 at 16:16 +0200, Anton Khirnov wrote:
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> Quoting Carotti, Elias via ffmpeg-devel (2023-10-11 12:54:21)
> > diff --git a/libavcodec/libx264.c b/libavcodec/libx264.c
> > index 77a9f173b4..85bd870f5d 100644
> > --- a/libavcodec/libx264.c
> > +++ b/libavcodec/libx264.c
> > @@ -726,7 +726,39 @@ FF_ENABLE_DEPRECATION_WARNINGS
> > 
> >      pkt->flags |= AV_PKT_FLAG_KEY*pic_out.b_keyframe;
> >      if (ret) {
> > -        ff_side_data_set_encoder_stats(pkt, (pic_out.i_qpplus1 -
> > 1) * FF_QP2LAMBDA, NULL, 0, pict_type);
> > +        const AVPixFmtDescriptor *pix_desc =
> > av_pix_fmt_desc_get(csp_to_pixfmt(pic_out.img.i_csp));
> 
> There's a problem here - we do not handle all values of i_csp.
> E.g. we have no equivalent of X264_CSP_NV12 | X264_CSP_HIGH_DEPTH,
> which
> x264 will use for YUV420P10 input.
> 
> The best solution is probably to use AVCodecContext.pix_fmt and
> assume
> that x264 doesn't do any nontrivial (i.e. other than interleaving and
> such) pixel format transformations internally.
> 


I see. Wouldn't not outputting the SSE values when csp_to_pixfmt()
returns AV_PIX_FMT_NONE work better? 
That wouldn't be worse than it is today (meaning that right now we
don't get those values for any pix_fmt).
Anyway, I did as you suggested and used AVCodecContext.pix_fmt.


> > <snip>
> > +            av_log(ctx, AV_LOG_DEBUG, "PSNR values from libx264:
> > %.3f %.3f %.3f.\n",
> > +                   pic_out.prop.f_psnr[0], pic_out.prop.f_psnr[1],
> > pic_out.prop.f_psnr[2]);
> 
> In my tests libx264 prints these values by itself, so this seems
> redundant.

removed.




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