Allow user to choose between I/P/B frames:
- normal
Ordinary IB..BPB..B GOP structure.
- low delay B-frames:
Allows forward-predict only for all B frames, L0 == L1, supported
on ICL+ platforms, required by VDENC(low_power).
- reference B-frames:
Convert P-frames to low delay B-frames, normal B frames still have
2 different ref_lists and allow bi-prediction.
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>
---
Further step for low delay B would be refining the reference management
to enable support for more forward-references in same ref_list.
doc/encoders.texi | 16 ++++++++++++++++
libavcodec/vaapi_encode.c | 20 +++++++++++++++-----
libavcodec/vaapi_encode.h | 1 +
libavcodec/vaapi_encode_h265.c | 32 +++++++++++++++++++++++++++++++-
4 files changed, 63 insertions(+), 6 deletions(-)
diff --git a/doc/encoders.texi b/doc/encoders.texi
index e23b6b3..1fb5ecf 100644
--- a/doc/encoders.texi
+++ b/doc/encoders.texi
@@ -3089,6 +3089,22 @@ 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 b_strategy
+Allow user to choose between I/P/B frames and specify the type of B-frames.
+@table @samp
+@item normal
+Normal IBBPBB strategy.
+
+@item low_delay_b
+Allows forward-predict only for all B frames, ref_list0 equals to ref_list1,
+supported on ICL+ platforms, required by VDENC(low_power).
+
+@item ref_b
+Convert P-frames to low delay B-frames as references, while normal B frames
+still have 2 different ref_lists and allow bi-prediction.
+@end table
+
@end table
@end table
diff --git a/libavcodec/vaapi_encode.c b/libavcodec/vaapi_encode.c
index 8ff720e..ea7efb6 100644
--- a/libavcodec/vaapi_encode.c
+++ b/libavcodec/vaapi_encode.c
@@ -1792,15 +1792,25 @@ static av_cold int
vaapi_encode_init_gop_structure(AVCodecContext *avctx)
"reference frames.\n");
return AVERROR(EINVAL);
} else if (!(ctx->codec->flags & FLAG_B_PICTURES) ||
- ref_l1 < 1 || avctx->max_b_frames < 1) {
- av_log(avctx, AV_LOG_VERBOSE, "Using intra and P-frames "
- "(supported references: %d / %d).\n", ref_l0, ref_l1);
+ ref_l1 < 1 || avctx->max_b_frames < 1 ||
+ ctx->b_frame_strategy == 1) {
+ if (ctx->b_frame_strategy == 1)
+ av_log(avctx, AV_LOG_VERBOSE, "Using intra and B -frames "
+ "(low delay) (supported references: %d / %d).\n",
+ ref_l0, ref_l1);
+ else
+ av_log(avctx, AV_LOG_VERBOSE, "Using intra and P-frames "
+ "(supported references: %d / %d).\n", ref_l0, ref_l1);
ctx->gop_size = avctx->gop_size;
ctx->p_per_i = INT_MAX;
ctx->b_per_p = 0;
} else {
- av_log(avctx, AV_LOG_VERBOSE, "Using intra, P- and B-frames "
- "(supported references: %d / %d).\n", ref_l0, ref_l1);
+ if (ctx->b_frame_strategy == 2)
+ av_log(avctx, AV_LOG_VERBOSE, "Using intra, P- and B-frames "
+ "(supported references: %d / %d).\n", ref_l0, ref_l1);
+ else
+ av_log(avctx, AV_LOG_VERBOSE, "Using intra, P- and B-frames "
+ "(supported references: %d / %d).\n", ref_l0, ref_l1);
ctx->gop_size = avctx->gop_size;
ctx->p_per_i = INT_MAX;
ctx->b_per_p = avctx->max_b_frames;
diff --git a/libavcodec/vaapi_encode.h b/libavcodec/vaapi_encode.h
index b9a3def..1feca6c 100644
--- a/libavcodec/vaapi_encode.h
+++ b/libavcodec/vaapi_encode.h
@@ -310,6 +310,7 @@ typedef struct VAAPIEncodeContext {
int idr_counter;
int gop_counter;
int end_of_stream;
+ int b_frame_strategy;
// Whether the driver supports ROI at all.
int roi_allowed;
diff --git a/libavcodec/vaapi_encode_h265.c b/libavcodec/vaapi_encode_h265.c
index 97dc5a7..cecde73 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 b_frame_strategy;
// 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->b_frame_strategy)
+ 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;
@@ -1052,10 +1056,13 @@ static int
vaapi_encode_h265_init_slice_params(AVCodecContext *avctx,
av_assert0(pic->type == PICTURE_TYPE_P ||
pic->type == PICTURE_TYPE_B);
vslice->ref_pic_list0[0] = vpic->reference_frames[0];
+ if (priv->b_frame_strategy == 1 && pic->type == PICTURE_TYPE_P)
+ // Reference for low delay B-frame, L0 == L1
+ vslice->ref_pic_list1[0] = vpic->reference_frames[0];
}
if (pic->nb_refs >= 2) {
- // Forward reference for B-frame.
av_assert0(pic->type == PICTURE_TYPE_B);
+ // Forward reference for B-frame.
vslice->ref_pic_list1[0] = vpic->reference_frames[1];
}
@@ -1181,6 +1188,21 @@ static av_cold int vaapi_encode_h265_init(AVCodecContext
*avctx)
if (priv->qp > 0)
ctx->explicit_qp = priv->qp;
+ // Low delay B-frames is required for low power encoding.
+ if (ctx->low_power && priv->b_frame_strategy != 1) {
+ priv->b_frame_strategy = 1;
+ av_log(avctx, AV_LOG_WARNING, "Low delay B-frames required "
+ "for low power encoding.\n");
+ }
+
+ if (priv->b_frame_strategy) {
+ ctx->b_frame_strategy = priv->b_frame_strategy;
+ if (ctx->b_frame_strategy == 1)
+ av_log(avctx, AV_LOG_VERBOSE, "Low delay B-frames enabled.\n");
+ else
+ av_log(avctx, AV_LOG_VERBOSE, "Reference B-frames enabled.\n");
+ }
+
return ff_vaapi_encode_init(avctx);
}
@@ -1256,6 +1278,14 @@ 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" },
+ { "b_strategy", "Strategy to choose between I/P/B-frames",
+ OFFSET(b_frame_strategy), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, FLAGS,
"b_strategy" },
+ { "normal", "Normal IB..BPB..B strategy",
+ 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, INT_MIN,
INT_MAX, FLAGS, "b_strategy" },
+ { "low_delay_b", "Use low delay B-frames with forward-prediction only",
+ 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, INT_MIN,
INT_MAX, FLAGS, "b_strategy" },
+ { "ref_b", "Only convert P-frames to low delay B-frames as
references",
+ 0, AV_OPT_TYPE_CONST, { .i64 = 2 }, INT_MIN,
INT_MAX, FLAGS, "b_strategy" },
{ 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".
