[FFmpeg-devel] [PATCH 3/5] libx265: Update ROI behaviour to match documentation

[Guo, Yejun]

> -----Original Message-----
> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of Mark Thompson
> Sent: Thursday, February 28, 2019 6:00 AM
> To: ffmpeg-devel at ffmpeg.org
> Subject: [FFmpeg-devel] [PATCH 3/5] libx265: Update ROI behaviour to
> match documentation
> 
> Equivalent to the previous patch for libx264.
> ---
>  libavcodec/libx265.c | 41 ++++++++++++++++++++---------------------
>  1 file changed, 20 insertions(+), 21 deletions(-)
> 
> diff --git a/libavcodec/libx265.c b/libavcodec/libx265.c
> index 98415366da..af1a2b2287 100644
> --- a/libavcodec/libx265.c
> +++ b/libavcodec/libx265.c
> @@ -296,27 +296,33 @@ static av_cold int
> libx265_encode_set_roi(libx265Context *ctx, const AVFrame *fr
>              int mb_size = (ctx->params->rc.qgSize == 8) ? 8 : 16;
>              int mbx = (frame->width + mb_size - 1) / mb_size;
>              int mby = (frame->height + mb_size - 1) / mb_size;
> +            int qp_range = 51 + 6 * (pic->bitDepth - 8);

just found following from "$ ./x265 --fullhelp", not sure what 69 means here. Shall we change our qoffset formula accordingly?
   --qpmin <integer>             sets a hard lower limit on QP allowed to ratecontrol. Default 0
   --qpmax <integer>             sets a hard upper limit on QP allowed to ratecontrol. Default 69


>              int nb_rois;
> -            AVRegionOfInterest *roi;
> +            const AVRegionOfInterest *roi;
>              float *qoffsets;         /* will be freed after encode is called. */
>              qoffsets = av_mallocz_array(mbx * mby, sizeof(*qoffsets));
>              if (!qoffsets)
>                  return AVERROR(ENOMEM);
> 
> -            nb_rois = sd->size / sizeof(AVRegionOfInterest);
> -            roi = (AVRegionOfInterest*)sd->data;
> -            for (int count = 0; count < nb_rois; count++) {
> -                int starty = FFMIN(mby, roi->top / mb_size);
> -                int endy   = FFMIN(mby, (roi->bottom + mb_size - 1)/ mb_size);
> -                int startx = FFMIN(mbx, roi->left / mb_size);
> -                int endx   = FFMIN(mbx, (roi->right + mb_size - 1)/ mb_size);
> +            roi = (const AVRegionOfInterest*)sd->data;
> +            if (!roi->self_size || sd->size % roi->self_size != 0) {
> +                av_log(ctx, AV_LOG_ERROR, "Invalid
> AVRegionOfInterest.self_size.\n");
> +                return AVERROR(EINVAL);
> +            }
> +            nb_rois = sd->size / roi->self_size;
> +
> +            // This list must be iterated in reverse because regions are
> +            // defined in order of decreasing importance.

same comments as libx264

> +            for (int i = nb_rois - 1; i >= 0; i--) {
> +                int startx, endx, starty, endy;
>                  float qoffset;
> 
> -                if (roi->self_size == 0) {
> -                    av_free(qoffsets);
> -                    av_log(ctx, AV_LOG_ERROR, "AVRegionOfInterest.self_size must
> be set to sizeof(AVRegionOfInterest).\n");
> -                    return AVERROR(EINVAL);
> -                }
> +                roi = (const AVRegionOfInterest*)(sd->data + roi->self_size * i);
> +
> +                starty = av_clip(roi->top / mb_size, 0, mby);
> +                endy   = av_clip((frame->height - roi->bottom + mb_size - 1) /
> mb_size, 0, mby);
> +                startx = av_clip(roi->left / mb_size, 0, mbx);
> +                endx   = av_clip((frame->width - roi->right + mb_size - 1) / mb_size,
> 0, mbx);

same comments as libx264

> 
>                  if (roi->qoffset.den == 0) {
>                      av_free(qoffsets);
> @@ -324,18 +330,11 @@ static av_cold int
> libx265_encode_set_roi(libx265Context *ctx, const AVFrame *fr
>                      return AVERROR(EINVAL);
>                  }
>                  qoffset = roi->qoffset.num * 1.0f / roi->qoffset.den;
> -                qoffset = av_clipf(qoffset, -1.0f, 1.0f);
> -
> -                /* qp range of x265 is from 0 to 51, just choose 25 as the scale value,
> -                 * so the range of final qoffset is [-25.0, 25.0].
> -                 */
> -                qoffset = qoffset * 25;
> +                qoffset = av_clipf(qoffset * qp_range, -qp_range, +qp_range);
> 
>                  for (int y = starty; y < endy; y++)
>                      for (int x = startx; x < endx; x++)
>                          qoffsets[x + y*mbx] = qoffset;
> -
> -                roi = (AVRegionOfInterest*)((char*)roi + roi->self_size);
>              }
> 
>              pic->quantOffsets = qoffsets;
> --
> 2.19.2
> 
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