Low delay B-frame is supported on ICL+ platform. For low power encoding, low_delay_b should be enabled by default.
Low delay B: <http://what-when-how.com/Tutorial/topic-397pct9eq3/High-Efficiency-Video-Coding-HEVC-288.html> There is an on-going work in libva and media-driver to add querys support for low delay b, would add it once it's ready: https://github.com/intel/libva/pull/220 https://github.com/intel/libva/pull/364 https://github.com/intel/media-driver/issues/721 Signed-off-by: Linjie Fu <linjie...@intel.com> --- doc/encoders.texi | 8 ++++++++ libavcodec/vaapi_encode_h265.c | 19 +++++++++++++++++-- 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/doc/encoders.texi b/doc/encoders.texi index e23b6b3..b0812be 100644 --- a/doc/encoders.texi +++ b/doc/encoders.texi @@ -3089,6 +3089,14 @@ Some combination of the following values: Include HDR metadata if the input frames have it (@emph{mastering_display_colour_volume} and @emph{content_light_level} messages). + +@item low_delay_b +Use low delay B-frames instead of P frames. Reordering of pictures is +not allowed. The first picture is encoded as an I picture and subsequent +pictures are encoded as B pictures. Moreover, since past B pictures are +used for prediction, a low coding delay but with higher coding efficiency +(because of bi-prediction) is achieved. + @end table @end table diff --git a/libavcodec/vaapi_encode_h265.c b/libavcodec/vaapi_encode_h265.c index 97dc5a7..cd48545 100644 --- a/libavcodec/vaapi_encode_h265.c +++ b/libavcodec/vaapi_encode_h265.c @@ -62,6 +62,7 @@ typedef struct VAAPIEncodeH265Context { int tier; int level; int sei; + int low_delay_b; // Derived settings. int fixed_qp_idr; @@ -894,6 +895,9 @@ static int vaapi_encode_h265_init_slice_params(AVCodecContext *avctx, sh->slice_type = hpic->slice_type; + if (sh->slice_type == HEVC_SLICE_P && priv->low_delay_b) + sh->slice_type = HEVC_SLICE_B; + sh->slice_pic_order_cnt_lsb = hpic->pic_order_cnt & (1 << (sps->log2_max_pic_order_cnt_lsb_minus4 + 4)) - 1; @@ -1054,9 +1058,13 @@ static int vaapi_encode_h265_init_slice_params(AVCodecContext *avctx, vslice->ref_pic_list0[0] = vpic->reference_frames[0]; } if (pic->nb_refs >= 2) { - // Forward reference for B-frame. av_assert0(pic->type == PICTURE_TYPE_B); - vslice->ref_pic_list1[0] = vpic->reference_frames[1]; + if (priv->low_delay_b) + // Reference for low delay B-frame + vslice->ref_pic_list1[0] = vpic->reference_frames[0]; + else + // Forward reference for B-frame. + vslice->ref_pic_list1[0] = vpic->reference_frames[1]; } return 0; @@ -1181,6 +1189,11 @@ static av_cold int vaapi_encode_h265_init(AVCodecContext *avctx) if (priv->qp > 0) ctx->explicit_qp = priv->qp; + /* low_delay_b is required for low power encoding */ + priv->low_delay_b = ctx->low_power ? 1 : priv->low_delay_b; + if (priv->low_delay_b) + av_log(avctx, AV_LOG_VERBOSE, "Low delay B-frame enabled.\n"); + return ff_vaapi_encode_init(avctx); } @@ -1256,6 +1269,8 @@ static const AVOption vaapi_encode_h265_options[] = { 0, AV_OPT_TYPE_CONST, { .i64 = SEI_MASTERING_DISPLAY | SEI_CONTENT_LIGHT_LEVEL }, INT_MIN, INT_MAX, FLAGS, "sei" }, + { "low_delay_b", "Use low delay B frames instead of P frames", + OFFSET(low_delay_b), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS }, { NULL }, }; -- 2.7.4 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
