[FFmpeg-devel] [PATCH v2] libavcodec/qsvenc: Use parameter from AVCodecContext to reset qsv codec

[Xiang, Haihao]

On Thu, 2022-07-14 at 16:43 +0800, Wenbin Chen wrote:
> Using parameter from AVCodecContext to reset qsv codec is more suitable
> for MFXVideoENCODE_Reset()'s usage. Per-frame metadata is more suitable
> for the usage of mfxEncodeCtrl being passed to
> MFXVideoENCODE_EncodeFrameAsync(). Now change it to use the value
> from AVCodecContext.
> Because q->param is passed to both "in" and "out" parameters when call
> MFXVideoENCODE_Query(), the value in q->param may be changed. New
> variables are added to store old configuration, so that we can detect
> real parameter change.
> 
> Signed-off-by: Wenbin Chen <wenbin.chen at intel.com>
> ---
>  doc/encoders.texi   |  9 +++++---
>  libavcodec/qsvenc.c | 50 ++++++++++++++++++++++-----------------------
>  libavcodec/qsvenc.h |  6 ++++++
>  3 files changed, 36 insertions(+), 29 deletions(-)
> 
> diff --git a/doc/encoders.texi b/doc/encoders.texi
> index 02a91ffe96..6d73f74196 100644
> --- a/doc/encoders.texi
> +++ b/doc/encoders.texi
> @@ -3337,10 +3337,13 @@ For encoders set this flag to ON to reduce power
> consumption and GPU usage.
>  Following options can be used durning qsv encoding.
>  
>  @table @option
> - at item @var{qsv_config_qp}
> + at item @var{global_quality}
> + at item @var{i_quant_factor}
> + at item @var{i_quant_offset}
> + at item @var{b_quant_factor}
> + at item @var{b_quant_offset}
>  Supported in h264_qsv and hevc_qsv.
> -This option can be set in per-frame metadata. QP parameter can be dynamically
> -changed when encoding in CQP mode.
> +Change these value to reset qsv codec's qp configuration.
>  @end table
>  
>  @subsection H264 options
> diff --git a/libavcodec/qsvenc.c b/libavcodec/qsvenc.c
> index 2382c2f5f7..c817577c23 100644
> --- a/libavcodec/qsvenc.c
> +++ b/libavcodec/qsvenc.c
> @@ -738,6 +738,11 @@ static int init_video_param(AVCodecContext *avctx,
> QSVEncContext *q)
>          q->param.mfx.QPI = av_clip(quant * fabs(avctx->i_quant_factor) +
> avctx->i_quant_offset, 0, 51);
>          q->param.mfx.QPP = av_clip(quant, 0, 51);
>          q->param.mfx.QPB = av_clip(quant * fabs(avctx->b_quant_factor) +
> avctx->b_quant_offset, 0, 51);
> +        q->old_global_quality = avctx->global_quality;
> +        q->old_i_quant_factor = avctx->i_quant_factor;
> +        q->old_i_quant_offset = avctx->i_quant_offset;
> +        q->old_b_quant_factor = avctx->b_quant_factor;
> +        q->old_b_quant_offset = avctx->b_quant_offset;
>  
>          break;
>  #if QSV_HAVE_AVBR
> @@ -1621,38 +1626,31 @@ static int set_roi_encode_ctrl(AVCodecContext *avctx,
> const AVFrame *frame,
>      return 0;
>  }
>  
> -static int update_qp(AVCodecContext *avctx, QSVEncContext *q,
> -                     const AVFrame *frame)
> +static int update_qp(AVCodecContext *avctx, QSVEncContext *q)
>  {
> -    int updated = 0, qp = 0, new_qp;
> -    char *tail;
> -    AVDictionaryEntry *entry = NULL;
> +    int updated = 0, new_qp = 0;
>  
>      if (avctx->codec_id != AV_CODEC_ID_H264 && avctx->codec_id !=
> AV_CODEC_ID_HEVC)
>          return 0;
>  
> -    entry = av_dict_get(frame->metadata, "qsv_config_qp", NULL, 0);
> -    if (entry && q->param.mfx.RateControlMethod == MFX_RATECONTROL_CQP) {
> -        qp = strtol(entry->value, &tail, 10);
> -        if (*tail) {
> -            av_log(avctx, AV_LOG_WARNING, "Invalid qsv_config_qp string.
> Ignore this metadata\n");
> +    if (q->param.mfx.RateControlMethod == MFX_RATECONTROL_CQP) {
> +        UPDATE_PARAM(q->old_global_quality, avctx->global_quality);
> +        UPDATE_PARAM(q->old_i_quant_factor, avctx->i_quant_factor);
> +        UPDATE_PARAM(q->old_i_quant_offset, avctx->i_quant_offset);
> +        UPDATE_PARAM(q->old_b_quant_factor, avctx->b_quant_factor);
> +        UPDATE_PARAM(q->old_b_quant_offset, avctx->b_quant_offset);
> +        if (!updated)
>              return 0;
> -        }
> -        if (qp < 0 || qp > 51) {
> -            av_log(avctx, AV_LOG_WARNING, "Invalid qp, clip to 0 ~ 51\n");
> -            qp = av_clip(qp, 0, 51);
> -        }
> -        av_log(avctx, AV_LOG_DEBUG, "Configure qp: %d\n",qp);
> -        UPDATE_PARAM(q->param.mfx.QPP, qp);
> -        new_qp = av_clip(qp * fabs(avctx->i_quant_factor) +
> -                            avctx->i_quant_offset, 0, 51);
> -        UPDATE_PARAM(q->param.mfx.QPI, new_qp);
> -        new_qp = av_clip(qp * fabs(avctx->b_quant_factor) +
> -                            avctx->b_quant_offset, 0, 51);
> -        UPDATE_PARAM(q->param.mfx.QPB, new_qp);
> +
> +        new_qp = avctx->global_quality / FF_QP2LAMBDA;
> +        q->param.mfx.QPI = av_clip(new_qp * fabs(avctx->i_quant_factor) +
> +                                    avctx->i_quant_offset, 0, 51);
> +        q->param.mfx.QPP = av_clip(new_qp, 0, 51);
> +        q->param.mfx.QPB = av_clip(new_qp * fabs(avctx->b_quant_factor) +
> +                                    avctx->b_quant_offset, 0, 51);
>          av_log(avctx, AV_LOG_DEBUG,
> -                "using fixed qp = %d/%d/%d for idr/p/b frames\n",
> -                q->param.mfx.QPI, q->param.mfx.QPP, q->param.mfx.QPB);
> +               "Reset qp = %d/%d/%d for idr/p/b frames\n",
> +               q->param.mfx.QPI, q->param.mfx.QPP, q->param.mfx.QPB);
>      }
>      return updated;
>  }
> @@ -1665,7 +1663,7 @@ static int update_parameters(AVCodecContext *avctx,
> QSVEncContext *q,
>      if (!frame)
>          return 0;
>  
> -    needReset = update_qp(avctx, q, frame);
> +    needReset = update_qp(avctx, q);
>      if (!needReset)
>          return 0;
>  
> diff --git a/libavcodec/qsvenc.h b/libavcodec/qsvenc.h
> index b754ac4b56..bffe957526 100644
> --- a/libavcodec/qsvenc.h
> +++ b/libavcodec/qsvenc.h
> @@ -224,6 +224,12 @@ typedef struct QSVEncContext {
>      int min_qp_p;
>      int max_qp_b;
>      int min_qp_b;
> +    // These are used for qp reset
> +    int old_global_quality;
> +    float old_i_quant_factor;
> +    float old_i_quant_offset;
> +    float old_b_quant_factor;
> +    float old_b_quant_offset;
>  } QSVEncContext;
>  
>  int ff_qsv_enc_init(AVCodecContext *avctx, QSVEncContext *q);

LGTM, will apply.

Thanks
Haihao