[FFmpeg-devel] [PATCH] Adds support for constant quality mode in VP9.

[James Zern]

On Wed, Aug 27, 2014 at 1:04 PM, Deb Mukherjee <debargha at google.com> wrote:
> Changes in the parameter mapping for libvpx to support the constant
> quality mode in VP9. The assumption in the patch is that if crf is
> provided but bitrate is 0, then the 'constant quality' mode of VP9
> is used. However if both are present, the 'constrained quality' mode
> is used as before.
> ---
>  libavcodec/libvpxenc.c | 25 +++++++++++++++++++------
>  1 file changed, 19 insertions(+), 6 deletions(-)
>

lgtm. builds all right with a recent lib and seems to have the desired effect.

> diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
> index 830a793..17205bf 100644
> --- a/libavcodec/libvpxenc.c
> +++ b/libavcodec/libvpxenc.c
> @@ -300,14 +300,22 @@ static av_cold int vpx_init(AVCodecContext *avctx,
>          enccfg.g_pass = VPX_RC_ONE_PASS;
>
>      if (avctx->rc_min_rate == avctx->rc_max_rate &&
> -        avctx->rc_min_rate == avctx->bit_rate && avctx->bit_rate)
> +        avctx->rc_min_rate == avctx->bit_rate && avctx->bit_rate) {
>          enccfg.rc_end_usage = VPX_CBR;
> -    else if (ctx->crf)
> +    } else if (ctx->crf >= 0) {
>          enccfg.rc_end_usage = VPX_CQ;
> +#if CONFIG_LIBVPX_VP9_ENCODER
> +        if (!avctx->bit_rate && avctx->codec_id == AV_CODEC_ID_VP9)
> +            enccfg.rc_end_usage = VPX_Q;
> +#endif
> +    }
>
>      if (avctx->bit_rate) {
>          enccfg.rc_target_bitrate = av_rescale_rnd(avctx->bit_rate, 1, 1000,
> -                                                AV_ROUND_NEAR_INF);
> +                                                  AV_ROUND_NEAR_INF);
> +#if CONFIG_LIBVPX_VP9_ENCODER
> +    } else if (enccfg.rc_end_usage == VPX_Q) {
> +#endif
>      } else {
>          if (enccfg.rc_end_usage == VPX_CQ) {
>              enccfg.rc_target_bitrate = 1000000;
> @@ -324,7 +332,11 @@ static av_cold int vpx_init(AVCodecContext *avctx,
>      if (avctx->qmax >= 0)
>          enccfg.rc_max_quantizer = avctx->qmax;
>
> -    if (enccfg.rc_end_usage == VPX_CQ) {
> +    if (enccfg.rc_end_usage == VPX_CQ
> +#if CONFIG_LIBVPX_VP9_ENCODER
> +        || enccfg.rc_end_usage == VPX_Q
> +#endif
> +        ) {
>          if (ctx->crf < enccfg.rc_min_quantizer || ctx->crf > enccfg.rc_max_quantizer) {
>                  av_log(avctx, AV_LOG_ERROR,
>                         "CQ level must be between minimum and maximum quantizer value (%d-%d)\n",
> @@ -430,7 +442,8 @@ static av_cold int vpx_init(AVCodecContext *avctx,
>      if (avctx->codec_id == AV_CODEC_ID_VP8)
>          codecctl_int(avctx, VP8E_SET_TOKEN_PARTITIONS,  av_log2(avctx->slices));
>      codecctl_int(avctx, VP8E_SET_STATIC_THRESHOLD,  avctx->mb_threshold);
> -    codecctl_int(avctx, VP8E_SET_CQ_LEVEL,          ctx->crf);
> +    if (ctx->crf >= 0)
> +        codecctl_int(avctx, VP8E_SET_CQ_LEVEL,          ctx->crf);
>      if (ctx->max_intra_rate >= 0)
>          codecctl_int(avctx, VP8E_SET_MAX_INTRA_BITRATE_PCT, ctx->max_intra_rate);
>
> @@ -775,7 +788,7 @@ static int vp8_encode(AVCodecContext *avctx, AVPacket *pkt,
>                           "by the bool decoder, meaning that partitions can be decoded even " \
>                           "though earlier partitions have been lost. Note that intra predicition" \
>                           " is still done over the partition boundary.",       0, AV_OPT_TYPE_CONST, {.i64 = VPX_ERROR_RESILIENT_PARTITIONS}, 0, 0, VE, "er"}, \
> -    { "crf",              "Select the quality for constant quality mode", offsetof(VP8Context, crf), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 63, VE }, \
> +    { "crf",              "Select the quality for constant quality mode", offsetof(VP8Context, crf), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 63, VE }, \
>
>  #define LEGACY_OPTIONS \
>      {"speed", "", offsetof(VP8Context, cpu_used), AV_OPT_TYPE_INT, {.i64 = 1}, -16, 16, VE}, \
> --
> 2.1.0.rc2.206.gedb03e5
>
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