[FFmpeg-devel] [PATCH 8/9] avcodec/nvenc: use encoder level options for qmin/qmax

Zhao Zhili quinkblack at foxmail.com
Fri Jan 31 08:16:06 EET 2025



> On Jan 31, 2025, at 03:40, Timo Rothenpieler <timo at rothenpieler.org> wrote:
> 
> AV1 uses a vastly different range than what the global options permit,
> and also for the other codecs the range of the global options is at
> least misaligned.

It ’s simpler to update qmin upper threshold than add qmin/qmax for each encoder.
And there is no mismatch issue between global options and local options.

> 
> Fixes #11365
> ---
> libavcodec/nvenc.c      | 49 +++++++++++++++++++++++++----------------
> libavcodec/nvenc.h      |  2 ++
> libavcodec/nvenc_av1.c  |  4 ++++
> libavcodec/nvenc_h264.c |  4 ++++
> libavcodec/nvenc_hevc.c |  4 ++++
> 5 files changed, 44 insertions(+), 19 deletions(-)
> 
> diff --git a/libavcodec/nvenc.c b/libavcodec/nvenc.c
> index a528f1ce93..a5c507150c 100644
> --- a/libavcodec/nvenc.c
> +++ b/libavcodec/nvenc.c
> @@ -893,8 +893,8 @@ static av_cold void set_constqp(AVCodecContext *avctx)
>             rc->constQP.qpIntra = av_clip(ctx->cqp * fabs(avctx->i_quant_factor) + avctx->i_quant_offset + 0.5, 0, qmax);
>     }
> 
> -    avctx->qmin = -1;
> -    avctx->qmax = -1;
> +    avctx->qmin = ctx->qmin = -1;
> +    avctx->qmax = ctx->qmax = -1;
> }
> 
> static av_cold void set_vbr(AVCodecContext *avctx)
> @@ -908,27 +908,37 @@ static av_cold void set_vbr(AVCodecContext *avctx)
>     int qmax = 51;
> #endif
> 
> -    if (avctx->qmin >= 0 && avctx->qmax >= 0) {
> +    if (avctx->qmin >= 0 || avctx->qmax >= 0)
> +        av_log(avctx, AV_LOG_WARNING, "Passing qmin/qmax via global AVCodecContext options. Use encoder options instead.\n");
> +
> +    if (avctx->qmin >= 0 && ctx->qmin < 0)
> +        ctx->qmin = avctx->qmin;
> +    if (avctx->qmax >= 0 && ctx->qmax < 0)
> +        ctx->qmax = avctx->qmax;
> +    avctx->qmin = ctx->qmin;
> +    avctx->qmax = ctx->qmax;
> +
> +    if (ctx->qmin >= 0 && ctx->qmax >= 0) {
>         rc->enableMinQP = 1;
>         rc->enableMaxQP = 1;
> 
> -        rc->minQP.qpInterB = avctx->qmin;
> -        rc->minQP.qpInterP = avctx->qmin;
> -        rc->minQP.qpIntra  = avctx->qmin;
> +        rc->minQP.qpInterB = ctx->qmin;
> +        rc->minQP.qpInterP = ctx->qmin;
> +        rc->minQP.qpIntra  = ctx->qmin;
> 
> -        rc->maxQP.qpInterB = avctx->qmax;
> -        rc->maxQP.qpInterP = avctx->qmax;
> -        rc->maxQP.qpIntra = avctx->qmax;
> +        rc->maxQP.qpInterB = ctx->qmax;
> +        rc->maxQP.qpInterP = ctx->qmax;
> +        rc->maxQP.qpIntra = ctx->qmax;
> 
> -        qp_inter_p = (avctx->qmax + 3 * avctx->qmin) / 4; // biased towards Qmin
> -    } else if (avctx->qmin >= 0) {
> +        qp_inter_p = (ctx->qmax + 3 * ctx->qmin) / 4; // biased towards Qmin
> +    } else if (ctx->qmin >= 0) {
>         rc->enableMinQP = 1;
> 
> -        rc->minQP.qpInterB = avctx->qmin;
> -        rc->minQP.qpInterP = avctx->qmin;
> -        rc->minQP.qpIntra = avctx->qmin;
> +        rc->minQP.qpInterB = ctx->qmin;
> +        rc->minQP.qpInterP = ctx->qmin;
> +        rc->minQP.qpIntra = ctx->qmin;
> 
> -        qp_inter_p = avctx->qmin;
> +        qp_inter_p = ctx->qmin;
>     } else {
>         qp_inter_p = 26; // default to 26
>     }
> @@ -974,8 +984,8 @@ static av_cold void set_lossless(AVCodecContext *avctx)
>     rc->constQP.qpInterP = 0;
>     rc->constQP.qpIntra  = 0;
> 
> -    avctx->qmin = -1;
> -    avctx->qmax = -1;
> +    avctx->qmin = ctx->qmin = -1;
> +    avctx->qmax = ctx->qmax = -1;
> }
> 
> static void nvenc_override_rate_control(AVCodecContext *avctx)
> @@ -989,7 +999,7 @@ static void nvenc_override_rate_control(AVCodecContext *avctx)
>         return;
> #ifndef NVENC_NO_DEPRECATED_RC
>     case NV_ENC_PARAMS_RC_VBR_MINQP:
> -        if (avctx->qmin < 0) {
> +        if (avctx->qmin < 0 && ctx->qmin < 0) {
>             av_log(avctx, AV_LOG_WARNING,
>                    "The variable bitrate rate-control requires "
>                    "the 'qmin' option set.\n");
> @@ -1112,7 +1122,8 @@ static av_cold int nvenc_setup_rate_control(AVCodecContext *avctx)
>             ctx->rc = NV_ENC_PARAMS_RC_CONSTQP;
>         } else if (ctx->twopass) {
>             ctx->rc = NV_ENC_PARAMS_RC_VBR_HQ;
> -        } else if (avctx->qmin >= 0 && avctx->qmax >= 0) {
> +        } else if ((avctx->qmin >= 0 && avctx->qmax >= 0) ||
> +                   (ctx->qmin >= 0 && ctx->qmax >= 0)) {
>             ctx->rc = NV_ENC_PARAMS_RC_VBR_MINQP;
>         }
>     }
> diff --git a/libavcodec/nvenc.h b/libavcodec/nvenc.h
> index 77aef3f188..f84adbdd55 100644
> --- a/libavcodec/nvenc.h
> +++ b/libavcodec/nvenc.h
> @@ -273,6 +273,8 @@ typedef struct NvencContext
>     float quality;
>     int aud;
>     int bluray_compat;
> +    int qmin;
> +    int qmax;
>     int init_qp_p;
>     int init_qp_b;
>     int init_qp_i;
> diff --git a/libavcodec/nvenc_av1.c b/libavcodec/nvenc_av1.c
> index 5dd27fe872..ceb046e4be 100644
> --- a/libavcodec/nvenc_av1.c
> +++ b/libavcodec/nvenc_av1.c
> @@ -119,6 +119,10 @@ static const AVOption options[] = {
>                                                             OFFSET(qp_cb_offset), AV_OPT_TYPE_INT,   { .i64 = 0 }, -12, 12, VE },
>     { "qp_cr_offset", "Quantization parameter offset for cr channel",
>                                                             OFFSET(qp_cr_offset), AV_OPT_TYPE_INT,   { .i64 = 0 }, -12, 12, VE },
> +    { "qmin",         "Specifies the minimum QP used for rate control",
> +                                                            OFFSET(qmin),         AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, 255, VE },
> +    { "qmax",         "Specifies the maximum QP used for rate control",
> +                                                            OFFSET(qmax),         AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, 255, VE },
>     { "no-scenecut",  "When lookahead is enabled, set this to 1 to disable adaptive I-frame insertion at scene cuts",
>                                                             OFFSET(no_scenecut),  AV_OPT_TYPE_BOOL,  { .i64 = 0 }, 0, 1, VE },
>     { "forced-idr",   "If forcing keyframes, force them as IDR frames.",
> diff --git a/libavcodec/nvenc_h264.c b/libavcodec/nvenc_h264.c
> index 5e9f73412f..c7267a082a 100644
> --- a/libavcodec/nvenc_h264.c
> +++ b/libavcodec/nvenc_h264.c
> @@ -174,6 +174,10 @@ static const AVOption options[] = {
>                                                             OFFSET(qp_cb_offset), AV_OPT_TYPE_INT,   { .i64 = 0 }, -12, 12, VE },
>     { "qp_cr_offset", "Quantization parameter offset for cr channel",
>                                                             OFFSET(qp_cr_offset), AV_OPT_TYPE_INT,   { .i64 = 0 }, -12, 12, VE },
> +    { "qmin",         "Specifies the minimum QP used for rate control",
> +                                                            OFFSET(qmin),         AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, 51, VE },
> +    { "qmax",         "Specifies the maximum QP used for rate control",
> +                                                            OFFSET(qmax),         AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, 51, VE },
>     { "weighted_pred","Set 1 to enable weighted prediction",
>                                                             OFFSET(weighted_pred),AV_OPT_TYPE_INT,   { .i64 = 0 }, 0, 1, VE },
>     { "coder",        "Coder type",                         OFFSET(coder),        AV_OPT_TYPE_INT,   { .i64 = -1                                         },-1, 2, VE, .unit = "coder" },
> diff --git a/libavcodec/nvenc_hevc.c b/libavcodec/nvenc_hevc.c
> index f821eaee50..f1b7062902 100644
> --- a/libavcodec/nvenc_hevc.c
> +++ b/libavcodec/nvenc_hevc.c
> @@ -158,6 +158,10 @@ static const AVOption options[] = {
>                                                             OFFSET(qp_cb_offset), AV_OPT_TYPE_INT,   { .i64 = 0 }, -12, 12, VE },
>     { "qp_cr_offset", "Quantization parameter offset for cr channel",
>                                                             OFFSET(qp_cr_offset), AV_OPT_TYPE_INT,   { .i64 = 0 }, -12, 12, VE },
> +    { "qmin",         "Specifies the minimum QP used for rate control",
> +                                                            OFFSET(qmin),         AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, 51, VE },
> +    { "qmax",         "Specifies the maximum QP used for rate control",
> +                                                            OFFSET(qmax),         AV_OPT_TYPE_INT,   { .i64 = -1 }, -1, 51, VE },
>     { "weighted_pred","Set 1 to enable weighted prediction",
>                                                             OFFSET(weighted_pred),AV_OPT_TYPE_INT,   { .i64 = 0 }, 0, 1, VE },
> #ifdef NVENC_HAVE_HEVC_BFRAME_REF_MODE
> -- 
> 2.45.2
> 
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