From: Andriy Gelman <andriy.gel...@gmail.com>
HEVC standard supports multi-layer streams (ITU-T H.265 02/2018 Annex
F). Each NAL unit belongs to a particular layer defined by nuh_layer_id
in the header.
Currently, all NAL units that do not belong to a base layer are
automatically removed in ff_h2645_packet_split(). Some data may
therefore be lost when future filters/decoders are designed to support
multi-layer streams.
A better approach is to forward nuh_layer_id > 0 packets and let blocks
down the chain decide how to process them. The condition to remove
packets has been moved to hevcdec and cbs.
Found-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com>
Signed-off-by: Andriy Gelman <andriy.gel...@gmail.com>
---
libavcodec/cbs_h2645.c | 3 +++
libavcodec/h2645_parse.c | 7 +++----
libavcodec/h2645_parse.h | 5 +++++
libavcodec/hevc_parse.c | 2 ++
libavcodec/hevc_parser.c | 3 +++
libavcodec/hevcdec.c | 2 +-
6 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
index 88fa0029cd6..ae32078f246 100644
--- a/libavcodec/cbs_h2645.c
+++ b/libavcodec/cbs_h2645.c
@@ -565,6 +565,9 @@ static int
cbs_h2645_fragment_add_nals(CodedBitstreamContext *ctx,
AVBufferRef *ref;
size_t size = nal->size;
+ if (nal->nuh_layer_id > 0)
+ continue;
+
// Remove trailing zeroes.
while (size > 0 && nal->data[size - 1] == 0)
--size;
diff --git a/libavcodec/h2645_parse.c b/libavcodec/h2645_parse.c
index 4808f79a67f..0f3343004f9 100644
--- a/libavcodec/h2645_parse.c
+++ b/libavcodec/h2645_parse.c
@@ -292,23 +292,22 @@ static int get_bit_length(H2645NAL *nal, int
skip_trailing_zeros)
static int hevc_parse_nal_header(H2645NAL *nal, void *logctx)
{
GetBitContext *gb = &nal->gb;
- int nuh_layer_id;
if (get_bits1(gb) != 0)
return AVERROR_INVALIDDATA;
nal->type = get_bits(gb, 6);
- nuh_layer_id = get_bits(gb, 6);
+ nal->nuh_layer_id = get_bits(gb, 6);
nal->temporal_id = get_bits(gb, 3) - 1;
if (nal->temporal_id < 0)
return AVERROR_INVALIDDATA;
av_log(logctx, AV_LOG_DEBUG,
"nal_unit_type: %d(%s), nuh_layer_id: %d, temporal_id: %d\n",
- nal->type, hevc_nal_unit_name(nal->type), nuh_layer_id,
nal->temporal_id);
+ nal->type, hevc_nal_unit_name(nal->type), nal->nuh_layer_id,
nal->temporal_id);
- return nuh_layer_id == 0;
+ return 1;
}
static int h264_parse_nal_header(H2645NAL *nal, void *logctx)
diff --git a/libavcodec/h2645_parse.h b/libavcodec/h2645_parse.h
index 2acf882d3da..3e47f86c53b 100644
--- a/libavcodec/h2645_parse.h
+++ b/libavcodec/h2645_parse.h
@@ -56,6 +56,11 @@ typedef struct H2645NAL {
*/
int temporal_id;
+ /*
+ * HEVC only, identifier of layer to which nal unit belongs
+ */
+ int nuh_layer_id;
+
int skipped_bytes;
int skipped_bytes_pos_size;
int *skipped_bytes_pos;
diff --git a/libavcodec/hevc_parse.c b/libavcodec/hevc_parse.c
index dddb293df64..29dfd479f38 100644
--- a/libavcodec/hevc_parse.c
+++ b/libavcodec/hevc_parse.c
@@ -37,6 +37,8 @@ static int hevc_decode_nal_units(const uint8_t *buf, int
buf_size, HEVCParamSets
for (i = 0; i < pkt.nb_nals; i++) {
H2645NAL *nal = &pkt.nals[i];
+ if (nal->nuh_layer_id > 0)
+ continue;
/* ignore everything except parameter sets and VCL NALUs */
switch (nal->type) {
diff --git a/libavcodec/hevc_parser.c b/libavcodec/hevc_parser.c
index b444b999550..87d5dba4f5e 100644
--- a/libavcodec/hevc_parser.c
+++ b/libavcodec/hevc_parser.c
@@ -202,6 +202,9 @@ static int parse_nal_units(AVCodecParserContext *s, const
uint8_t *buf,
H2645NAL *nal = &ctx->pkt.nals[i];
GetBitContext *gb = &nal->gb;
+ if (nal->nuh_layer_id > 0)
+ continue;
+
switch (nal->type) {
case HEVC_NAL_VPS:
ff_hevc_decode_nal_vps(gb, avctx, ps);
diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index 8f1c162acee..bcd8e67944a 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -3077,7 +3077,7 @@ static int decode_nal_units(HEVCContext *s, const uint8_t
*buf, int length)
if (s->avctx->skip_frame >= AVDISCARD_ALL ||
(s->avctx->skip_frame >= AVDISCARD_NONREF
- && ff_hevc_nal_is_nonref(nal->type)))
+ && ff_hevc_nal_is_nonref(nal->type)) || nal->nuh_layer_id > 0)
continue;
ret = decode_nal_unit(s, nal);
--
2.24.0
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