[FFmpeg-devel] [PATCH] libavcodec/qsvenc: enable LowDelayBRC and MaxFrameSizeI/MaxFrameSizeP for more accurate bitrate control

Xiang, Haihao haihao.xiang at intel.com
Mon Mar 21 07:03:54 EET 2022


On Thu, 2022-03-10 at 10:11 +0000, He, Fan F wrote:
> Feature introduction of LowDelayBRC, MaxFrameSizeI and MaxFrameSizeP could be
> found here:
> https://github.com/Intel-Media-SDK/MediaSDK/blob/master/doc/mediasdk-man.md
> 
> Signed-off-by: Dmitry Ermilov <dmitry.ermilov at intel.com>
> Signed-off-by: Fan F He <fan.f.he at intel.com>
> ---
>  doc/encoders.texi   | 26 ++++++++++++++++++++++++++
>  libavcodec/qsvenc.c | 17 +++++++++++++++++
>  libavcodec/qsvenc.h |  6 ++++++
>  3 files changed, 49 insertions(+)
> 
> diff --git a/doc/encoders.texi b/doc/encoders.texi
> index 1bd38671ca..47c8577e09 100644
> --- a/doc/encoders.texi
> +++ b/doc/encoders.texi
> @@ -3264,6 +3264,14 @@ Enable rate distortion optimization.
>  @item @var{max_frame_size}
>  Maximum encoded frame size in bytes.
>  
> + at item @var{max_frame_size_i}
> +Maximum encoded frame size for I frames in bytes. If this value is set as
> larger
> +than zero, then for I frames the value set by max_frame_size is ignored.
> +
> + at item @var{max_frame_size_p}
> +Maximum encoded frame size for P frames in bytes. If this value is set as
> larger
> +than zero, then for P frames the value set by max_frame_size is ignored.
> +
>  @item @var{max_slice_size}
>  Maximum encoded slice size in bytes.
>  
> @@ -3280,6 +3288,11 @@ Setting this flag enables macroblock level bitrate
> control that generally
>  improves subjective visual quality. Enabling this flag may have negative
> impact
>  on performance and objective visual quality metric.
>  
> + at item @var{low_delay_brc}
> +Setting this flag turns on or off LowDelayBRC feautre in qsv plugin, which
> provides
> +more accurate bitrate control to minimize the variance of bitstream size
> frame
> +by frame. Value: -1-default 0-off 1-on
> +
>  @item @var{adaptive_i}
>  This flag controls insertion of I frames by the QSV encoder. Turn ON this
> flag
>  to allow changing of frame type from P and B to I.
> @@ -3392,6 +3405,14 @@ Enable rate distortion optimization.
>  @item @var{max_frame_size}
>  Maximum encoded frame size in bytes.
>  
> + at item @var{max_frame_size_i}
> +Maximum encoded frame size for I frames in bytes. If this value is set as
> larger
> +than zero, then for I frames the value set by max_frame_size is ignored.
> +
> + at item @var{max_frame_size_p}
> +Maximum encoded frame size for P frames in bytes. If this value is set as
> larger
> +than zero, then for P frames the value set by max_frame_size is ignored.
> +
>  @item @var{max_slice_size}
>  Maximum encoded slice size in bytes.
>  
> @@ -3400,6 +3421,11 @@ Setting this flag enables macroblock level bitrate
> control that generally
>  improves subjective visual quality. Enabling this flag may have negative
> impact
>  on performance and objective visual quality metric.
>  
> + at item @var{low_delay_brc}
> +Setting this flag turns on or off LowDelayBRC feautre in qsv plugin, which
> provides
> +more accurate bitrate control to minimize the variance of bitstream size
> frame
> +by frame. Value: -1-default 0-off 1-on
> +
>  @item @var{p_strategy}
>  Enable P-pyramid: 0-default 1-simple 2-pyramid(bf need to be set to 0).
>  
> diff --git a/libavcodec/qsvenc.c b/libavcodec/qsvenc.c
> index 9b71487666..d5e2c5fb32 100644
> --- a/libavcodec/qsvenc.c
> +++ b/libavcodec/qsvenc.c
> @@ -374,6 +374,13 @@ static void dump_video_param(AVCodecContext *avctx,
> QSVEncContext *q,
>  #if QSV_VERSION_ATLEAST(1, 16)
>      av_log(avctx, AV_LOG_VERBOSE, "IntRefCycleDist: %"PRId16"\n", co3-
> >IntRefCycleDist);
>  #endif
> +#if QSV_VERSION_ATLEAST(1, 23)
> +    av_log(avctx, AV_LOG_VERBOSE, "LowDelayBRC: %s\n", print_threestate(co3-
> >LowDelayBRC));
> +#endif
> +#if QSV_VERSION_ATLEAST(1, 19)
> +    av_log(avctx, AV_LOG_VERBOSE, "MaxFrameSizeI: %d; ", co3->MaxFrameSizeI);
> +    av_log(avctx, AV_LOG_VERBOSE, "MaxFrameSizeP: %d\n", co3->MaxFrameSizeP);
> +#endif
>  }
>  
>  static void dump_video_vp9_param(AVCodecContext *avctx, QSVEncContext *q,
> @@ -988,6 +995,16 @@ static int init_video_param(AVCodecContext *avctx,
> QSVEncContext *q)
>  #if QSV_VERSION_ATLEAST(1, 16)
>              if (q->int_ref_cycle_dist >= 0)
>                  q->extco3.IntRefCycleDist = q->int_ref_cycle_dist;
> +#endif
> +#if QSV_VERSION_ATLEAST(1, 23)
> +            if (q->low_delay_brc >= 0)
> +                q->extco3.LowDelayBRC = q->low_delay_brc ?
> MFX_CODINGOPTION_ON : MFX_CODINGOPTION_OFF;
> +#endif
> +#if QSV_VERSION_ATLEAST(1, 19)
> +            if (q->max_frame_size_p >= 0)
> +                q->extco3.MaxFrameSizeI = q->max_frame_size_i;
> +            if (q->max_frame_size_p >= 0)
> +                q->extco3.MaxFrameSizeP = q->max_frame_size_p;
>  #endif
>          }
>  
> diff --git a/libavcodec/qsvenc.h b/libavcodec/qsvenc.h
> index 2bda858427..5e07580289 100644
> --- a/libavcodec/qsvenc.h
> +++ b/libavcodec/qsvenc.h
> @@ -91,6 +91,8 @@
>  { "veryslow",    NULL, 0, AV_OPT_TYPE_CONST, { .i64 =
> MFX_TARGETUSAGE_BEST_QUALITY  }, INT_MIN, INT_MAX, VE, "preset"
> },                                                \
>  { "rdo",            "Enable rate distortion
> optimization",    OFFSET(qsv.rdo),            AV_OPT_TYPE_INT, { .i64 = -1 },
> -1,          1, VE },                         \
>  { "max_frame_size", "Maximum encoded frame size in
> bytes",    OFFSET(qsv.max_frame_size), AV_OPT_TYPE_INT, { .i64 = -1 }, -1,
> UINT16_MAX, VE },                         \
> +{ "max_frame_size_i", "Maximum encoded I frame size in
> bytes",OFFSET(qsv.max_frame_size_i), AV_OPT_TYPE_INT, { .i64 = -1 }, -1,
> UINT16_MAX, VE },                       \
> +{ "max_frame_size_p", "Maximum encoded P frame size in
> bytes",OFFSET(qsv.max_frame_size_p), AV_OPT_TYPE_INT, { .i64 = -1 }, -1,
> UINT16_MAX, VE },                       \
>  { "max_slice_size", "Maximum encoded slice size in
> bytes",    OFFSET(qsv.max_slice_size), AV_OPT_TYPE_INT, { .i64 = -1 }, -1,
> UINT16_MAX, VE },                         \
>  { "bitrate_limit",  "Toggle bitrate
> limitations",             OFFSET(qsv.bitrate_limit),  AV_OPT_TYPE_INT, { .i64
> = -1 }, -1,          1, VE },                         \
>  { "mbbrc",          "MB level bitrate
> control",               OFFSET(qsv.mbbrc),          AV_OPT_TYPE_INT, { .i64 =
> -1 }, -1,          1, VE },                         \
> @@ -102,6 +104,7 @@
>  { "forced_idr",     "Forcing I frames as IDR
> frames",         OFFSET(qsv.forced_idr),     AV_OPT_TYPE_BOOL,{ .i64 =
> 0  },  0,          1, VE },                         \
>  { "low_power", "enable low power mode(experimental: many limitations by mfx
> version, BRC modes, etc.)", OFFSET(qsv.low_power), AV_OPT_TYPE_BOOL, { .i64 =
> -1}, -1, 1, VE},\
>  { "dblk_idc", "This option disable deblocking. It has value in range
> 0~2.",   OFFSET(qsv.dblk_idc),   AV_OPT_TYPE_INT,    { .i64 = 0
> },   0,  2,  VE},    \
> +{ "low_delay_brc",   "Allow to strictly obey avg frame size",
> OFFSET(qsv.low_delay_brc),  AV_OPT_TYPE_BOOL,{ .i64 = -1 }, -1,          1, VE
> },                         \
>  
>  extern const AVCodecHWConfigInternal *const ff_qsv_enc_hw_configs[];
>  
> @@ -173,6 +176,8 @@ typedef struct QSVEncContext {
>      int vcm;
>      int rdo;
>      int max_frame_size;
> +    int max_frame_size_i;
> +    int max_frame_size_p;
>      int max_slice_size;
>      int dblk_idc;
>  
> @@ -212,6 +217,7 @@ typedef struct QSVEncContext {
>      char *load_plugins;
>      SetEncodeCtrlCB *set_encode_ctrl_cb;
>      int forced_idr;
> +    int low_delay_brc;
>  } QSVEncContext;
>  
>  int ff_qsv_enc_init(AVCodecContext *avctx, QSVEncContext *q);

LGTM, will apply 

-Haihao



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