[FFmpeg-devel] [PATCH] videotoolboxenc: enable constant quality with -q:v on Apple Silicon Macs and use b-frames für HEVC and H264 and b-pyramid for HEVC.

Rick Kern kernrj at gmail.com
Fri Mar 19 20:54:16 EET 2021


On Fri, Jan 22, 2021 at 3:28 PM <simone at lisanet.de> wrote:

> From: Simone Karin Lehmann <simone at lisanet.de>
>
> Signed-off-by: Simone Karin Lehmann <simone at lisanet.de>
>

Applied

> ---
>  libavcodec/videotoolboxenc.c | 54 ++++++++++++++++++++++++++++--------
>  1 file changed, 42 insertions(+), 12 deletions(-)
>
> diff --git a/libavcodec/videotoolboxenc.c b/libavcodec/videotoolboxenc.c
> index 400401550a..e8cbc9dd4d 100644
> --- a/libavcodec/videotoolboxenc.c
> +++ b/libavcodec/videotoolboxenc.c
> @@ -224,7 +224,7 @@ typedef struct VTEncContext {
>      int64_t require_sw;
>
>      bool flushing;
> -    bool has_b_frames;
> +    int has_b_frames;
>      bool warned_color_range;
>
>      /* can't be bool type since AVOption will access it as int */
> @@ -1014,6 +1014,12 @@ static int get_cv_ycbcr_matrix(AVCodecContext
> *avctx, CFStringRef *matrix) {
>      return 0;
>  }
>
> +// constant quality only on Macs with Apple Silicon
> +static bool vtenc_qscale_enabled(void)
> +{
> +    return TARGET_OS_OSX && TARGET_CPU_ARM64;
> +}
> +
>  static int vtenc_create_encoder(AVCodecContext   *avctx,
>                                  CMVideoCodecType codec_type,
>                                  CFStringRef      profile_level,
> @@ -1025,7 +1031,9 @@ static int vtenc_create_encoder(AVCodecContext
>  *avctx,
>      VTEncContext *vtctx = avctx->priv_data;
>      SInt32       bit_rate = avctx->bit_rate;
>      SInt32       max_rate = avctx->rc_max_rate;
> +    Float32      quality = avctx->global_quality / FF_QP2LAMBDA;
>      CFNumberRef  bit_rate_num;
> +    CFNumberRef  quality_num;
>      CFNumberRef  bytes_per_second;
>      CFNumberRef  one_second;
>      CFArrayRef   data_rate_limits;
> @@ -1056,15 +1064,33 @@ static int vtenc_create_encoder(AVCodecContext
>  *avctx,
>          return AVERROR_EXTERNAL;
>      }
>
> -    bit_rate_num = CFNumberCreate(kCFAllocatorDefault,
> -                                  kCFNumberSInt32Type,
> -                                  &bit_rate);
> -    if (!bit_rate_num) return AVERROR(ENOMEM);
> +    if (avctx->flags & AV_CODEC_FLAG_QSCALE && !vtenc_qscale_enabled()) {
> +        av_log(avctx, AV_LOG_ERROR, "Error: -q:v qscale not available for
> encoder. Use -b:v bitrate instead.\n");
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (avctx->flags & AV_CODEC_FLAG_QSCALE) {
> +        quality = quality >= 100 ? 1.0 : quality / 100;
> +        quality_num = CFNumberCreate(kCFAllocatorDefault,
> +                                     kCFNumberFloat32Type,
> +                                     &quality);
> +        if (!quality_num) return AVERROR(ENOMEM);
>
> -    status = VTSessionSetProperty(vtctx->session,
> -
> kVTCompressionPropertyKey_AverageBitRate,
> -                                  bit_rate_num);
> -    CFRelease(bit_rate_num);
> +        status = VTSessionSetProperty(vtctx->session,
> +                                      kVTCompressionPropertyKey_Quality,
> +                                      quality_num);
> +        CFRelease(quality_num);
> +    } else {
> +        bit_rate_num = CFNumberCreate(kCFAllocatorDefault,
> +                                      kCFNumberSInt32Type,
> +                                      &bit_rate);
> +        if (!bit_rate_num) return AVERROR(ENOMEM);
> +
> +        status = VTSessionSetProperty(vtctx->session,
> +
> kVTCompressionPropertyKey_AverageBitRate,
> +                                      bit_rate_num);
> +        CFRelease(bit_rate_num);
> +    }
>
>      if (status) {
>          av_log(avctx, AV_LOG_ERROR, "Error setting bitrate property:
> %d\n", status);
> @@ -1333,6 +1359,7 @@ static int vtenc_configure_encoder(AVCodecContext
> *avctx)
>      }
>
>      vtctx->codec_id = avctx->codec_id;
> +    avctx->max_b_frames = 16;
>
>      if (vtctx->codec_id == AV_CODEC_ID_H264) {
>          vtctx->get_param_set_func =
> CMVideoFormatDescriptionGetH264ParameterSetAtIndex;
> @@ -1340,7 +1367,7 @@ static int vtenc_configure_encoder(AVCodecContext
> *avctx)
>          vtctx->has_b_frames = avctx->max_b_frames > 0;
>          if(vtctx->has_b_frames && vtctx->profile == H264_PROF_BASELINE){
>              av_log(avctx, AV_LOG_WARNING, "Cannot use B-frames with
> baseline profile. Output will not contain B-frames.\n");
> -            vtctx->has_b_frames = false;
> +            vtctx->has_b_frames = 0;
>          }
>
>          if (vtctx->entropy == VT_CABAC && vtctx->profile ==
> H264_PROF_BASELINE) {
> @@ -1353,6 +1380,8 @@ static int vtenc_configure_encoder(AVCodecContext
> *avctx)
>          vtctx->get_param_set_func =
> compat_keys.CMVideoFormatDescriptionGetHEVCParameterSetAtIndex;
>          if (!vtctx->get_param_set_func) return AVERROR(EINVAL);
>          if (!get_vt_hevc_profile_level(avctx, &profile_level)) return
> AVERROR(EINVAL);
> +        // HEVC has b-byramid
> +        vtctx->has_b_frames = avctx->max_b_frames > 0 ? 2 : 0;
>      }
>
>      enc_info = CFDictionaryCreateMutable(
> @@ -1448,7 +1477,8 @@ static av_cold int vtenc_init(AVCodecContext *avctx)
>
>      if (!status && has_b_frames_cfbool) {
>          //Some devices don't output B-frames for main profile, even if
> requested.
> -        vtctx->has_b_frames = CFBooleanGetValue(has_b_frames_cfbool);
> +        // HEVC has b-pyramid
> +        vtctx->has_b_frames = (CFBooleanGetValue(has_b_frames_cfbool) &&
> avctx->codec_id == AV_CODEC_ID_HEVC) ? 2 : 1;
>          CFRelease(has_b_frames_cfbool);
>      }
>      avctx->has_b_frames = vtctx->has_b_frames;
> @@ -2356,7 +2386,7 @@ static av_cold int vtenc_frame(
>
>          if (vtctx->frame_ct_in == 0) {
>              vtctx->first_pts = frame->pts;
> -        } else if(vtctx->frame_ct_in == 1 && vtctx->has_b_frames) {
> +        } else if(vtctx->frame_ct_in == vtctx->has_b_frames) {
>              vtctx->dts_delta = frame->pts - vtctx->first_pts;
>          }
>
> --
> 2.24.3 (Apple Git-128)
>
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