On 11/03/2022 09:00, Fei Wang wrote:
From: Linjie Fu <linjie...@intel.com>
Use GPB frames to replace regular P/B frames if backend driver does not
support it.
- GPB:
Generalized P and B picture. Regular P/B frames replaced by B
frames with previous-predict only, L0 == L1. Normal B frames
still have 2 different ref_lists and allow bi-prediction
Signed-off-by: Linjie Fu <linjie...@intel.com>
Signed-off-by: Fei Wang <fei.w.w...@intel.com>
---
update:
1. Add b to gpb.
2. Optimise debug message.
libavcodec/vaapi_encode.c | 74 +++++++++++++++++++++++++++++++---
libavcodec/vaapi_encode.h | 2 +
libavcodec/vaapi_encode_h265.c | 24 ++++++++++-
3 files changed, 93 insertions(+), 7 deletions(-)
diff --git a/libavcodec/vaapi_encode.c b/libavcodec/vaapi_encode.c
index 3bf379b1a0..bdba9726b2 100644
--- a/libavcodec/vaapi_encode.c
+++ b/libavcodec/vaapi_encode.c
@@ -848,9 +848,13 @@ static void vaapi_encode_set_b_pictures(AVCodecContext
*avctx,
pic->b_depth = current_depth;
vaapi_encode_add_ref(avctx, pic, start, 1, 1, 0);
- vaapi_encode_add_ref(avctx, pic, end, 1, 1, 0);
vaapi_encode_add_ref(avctx, pic, prev, 0, 0, 1);
+ if (!ctx->b_to_gpb)
+ vaapi_encode_add_ref(avctx, pic, end, 1, 1, 0);
+ else
+ vaapi_encode_add_ref(avctx, pic, end, 0, 1, 0);
This is doing something extremely dubious. If b-to-gpb is set, then don't use
the future reference? That means these pictures will only have the past
reference, and the coding efficiency will often be much worse.
E.g. if you have the default structure (max_b_frames = 2, max_b_depth = 1) then
in a sequence of four pictures you get:
1 referring to something previous
4 referring to 1
2 referring to 1 and 4
3 referring to 1 and 4
and this change means you lose the 2 -> 4 and 3 -> 4 references. Therefore, a
change in the picture between 1 and 2 will end up coded three times in 2, 3 and 4
rather than just being coded in 4 and then referred to by the others.
+
for (ref = end->refs[1]; ref; ref = ref->refs[1])
vaapi_encode_add_ref(avctx, pic, ref, 0, 1, 0);
}
@@ -871,8 +875,11 @@ static void vaapi_encode_set_b_pictures(AVCodecContext
*avctx,
vaapi_encode_add_ref(avctx, pic, pic, 0, 1, 0);
vaapi_encode_add_ref(avctx, pic, start, 1, 1, 0);
- vaapi_encode_add_ref(avctx, pic, end, 1, 1, 0);
vaapi_encode_add_ref(avctx, pic, prev, 0, 0, 1);
+ if (!ctx->b_to_gpb)
+ vaapi_encode_add_ref(avctx, pic, end, 1, 1, 0);
+ else
+ vaapi_encode_add_ref(avctx, pic, end, 0, 1, 0);
for (ref = end->refs[1]; ref; ref = ref->refs[1])
vaapi_encode_add_ref(avctx, pic, ref, 0, 1, 0);
@@ -1845,6 +1852,51 @@ static av_cold int
vaapi_encode_init_gop_structure(AVCodecContext *avctx)
ref_l1 = attr.value >> 16 & 0xffff;
}
+ ctx->p_to_gpb = 0;
+ ctx->b_to_gpb = 0;
+
+#if VA_CHECK_VERSION(1, 9, 0)
+ if (!(ctx->codec->flags & FLAG_INTRA_ONLY ||
+ avctx->gop_size <= 1)) {
+ attr = (VAConfigAttrib) { VAConfigAttribPredictionDirection };
+ vas = vaGetConfigAttributes(ctx->hwctx->display,
+ ctx->va_profile,
+ ctx->va_entrypoint,
+ &attr, 1);
+ if (vas != VA_STATUS_SUCCESS) {
+ av_log(avctx, AV_LOG_WARNING, "Failed to query prediction direction
"
+ "attribute: %d (%s).\n", vas, vaErrorStr(vas));
+ return AVERROR_EXTERNAL;
+ } else if (attr.value == VA_ATTRIB_NOT_SUPPORTED) {
+ av_log(avctx, AV_LOG_VERBOSE, "Driver does not report any additional
"
+ "prediction constraints.\n");
+ } else {
+ if (((ref_l0 > 0 || ref_l1 > 0) && !(attr.value &
VA_PREDICTION_DIRECTION_PREVIOUS)) ||
+ ((ref_l1 == 0) && (attr.value &
(VA_PREDICTION_DIRECTION_FUTURE | VA_PREDICTION_DIRECTION_BI_NOT_EMPTY)))) {
+ av_log(avctx, AV_LOG_ERROR, "Driver report incorrect prediction
"
+ "direction attribute.\n");
+ return AVERROR_EXTERNAL;
+ }
+
+ if (!(attr.value & VA_PREDICTION_DIRECTION_FUTURE)) {
+ if (ref_l0 > 0 && ref_l1 > 0) {
+ ctx->b_to_gpb = 1;
+ av_log(avctx, AV_LOG_VERBOSE, "Driver support previous
prediction "
+ "only for B-frames.\n");
+ }
+ }
Please note that the PREDICTION_DIRECTION_FUTURE/PREVIOUS options don't mean
anything for H.265.
The driver isn't told which direction the prediction is in, it's only told
about some reference frames and how to refer to them. Whether those frames are
in the past or future is unspecified and irrelevant - a P frame can refer to a
single future frame if it wants.
(I tried to argue this when it was added, but given that they are meaningless I
didn't argue very hard.)
I suspect you are trying to use this as a test of something else. Perhaps you
could explain what the test you actually want is?
+
+ if (attr.value & VA_PREDICTION_DIRECTION_BI_NOT_EMPTY) {
+ if (ref_l0 > 0 && ref_l1 > 0) {
+ ctx->p_to_gpb = 1;
+ av_log(avctx, AV_LOG_VERBOSE, "Driver does not support
P-frames, "
+ "replacing them with previous prediction only
B-frames.\n");
+ }
+ }
+ }
+ }
+#endif
...
- Mark
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