From: Zhao Zhili <zhiliz...@tencent.com>
For example, to extract alpha layer with nuh_layer_id equal
to 1:
./ffmpeg -i alpha.mp4 \
-an -c:v copy \
-bsf:v hevc_extract_layer=nuh_layer_id=1 \
output.mp4
Signed-off-by: Zhao Zhili <zhiliz...@tencent.com>
---
configure | 1 +
doc/bitstream_filters.texi | 12 +++
libavcodec/Makefile | 1 +
libavcodec/bitstream_filters.c | 1 +
libavcodec/hevc_extract_layer_bsf.c | 126 ++++++++++++++++++++++++++++
libavcodec/version.h | 4 +-
6 files changed, 143 insertions(+), 2 deletions(-)
create mode 100644 libavcodec/hevc_extract_layer_bsf.c
diff --git a/configure b/configure
index 870d426b0e..a398b28790 100755
--- a/configure
+++ b/configure
@@ -3278,6 +3278,7 @@ filter_units_bsf_select="cbs"
h264_metadata_bsf_deps="const_nan"
h264_metadata_bsf_select="cbs_h264"
h264_redundant_pps_bsf_select="cbs_h264"
+hevc_extract_layer_bsf_select="cbs_h265"
hevc_metadata_bsf_select="cbs_h265"
mjpeg2jpeg_bsf_select="jpegtables"
mpeg2_metadata_bsf_select="cbs_mpeg2"
diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index c63c20370f..55ed8d91f9 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -382,6 +382,18 @@ This applies a specific fixup to some Blu-ray streams
which contain
redundant PPSs modifying irrelevant parameters of the stream which
confuse other transformations which require correct extradata.
+@section hevc_extract_layer
+
+Extract NALUs with the specified nuh_layer_id and rewrite as base
+layer. Only works with INBL (independent non-base layer).
+
+@table @option
+
+@item nuh_layer_id
+Which layer to extract.
+
+@end table
+
@section hevc_metadata
Modify metadata embedded in an HEVC stream.
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 3ab448dd49..f27d169741 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -1208,6 +1208,7 @@ OBJS-$(CONFIG_H264_METADATA_BSF) +=
h264_metadata_bsf.o h264_levels.o \
OBJS-$(CONFIG_H264_MP4TOANNEXB_BSF) += h264_mp4toannexb_bsf.o
OBJS-$(CONFIG_H264_REDUNDANT_PPS_BSF) += h264_redundant_pps_bsf.o
OBJS-$(CONFIG_HAPQA_EXTRACT_BSF) += hapqa_extract_bsf.o hap.o
+OBJS-$(CONFIG_HEVC_EXTRACT_LAYER_BSF) += hevc_extract_layer_bsf.o
OBJS-$(CONFIG_HEVC_METADATA_BSF) += h265_metadata_bsf.o
h265_profile_level.o \
h2645data.o
OBJS-$(CONFIG_HEVC_MP4TOANNEXB_BSF) += hevc_mp4toannexb_bsf.o
diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
index a3bebefe5f..ac013e8072 100644
--- a/libavcodec/bitstream_filters.c
+++ b/libavcodec/bitstream_filters.c
@@ -40,6 +40,7 @@ extern const FFBitStreamFilter ff_h264_metadata_bsf;
extern const FFBitStreamFilter ff_h264_mp4toannexb_bsf;
extern const FFBitStreamFilter ff_h264_redundant_pps_bsf;
extern const FFBitStreamFilter ff_hapqa_extract_bsf;
+extern const FFBitStreamFilter ff_hevc_extract_layer_bsf;
extern const FFBitStreamFilter ff_hevc_metadata_bsf;
extern const FFBitStreamFilter ff_hevc_mp4toannexb_bsf;
extern const FFBitStreamFilter ff_imx_dump_header_bsf;
diff --git a/libavcodec/hevc_extract_layer_bsf.c
b/libavcodec/hevc_extract_layer_bsf.c
new file mode 100644
index 0000000000..84c1c87a80
--- /dev/null
+++ b/libavcodec/hevc_extract_layer_bsf.c
@@ -0,0 +1,126 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/common.h"
+#include "libavutil/opt.h"
+
+#include "bsf.h"
+#include "bsf_internal.h"
+#include "cbs.h"
+#include "cbs_bsf.h"
+#include "cbs_h265.h"
+#include "hevc.h"
+
+typedef struct HevcExtractLayerContext {
+ CBSBSFContext common;
+
+ int nuh_layer_id;
+} HevcExtractLayerContext;
+
+static int hevc_update_vps(AVBSFContext *bsf, H265RawVPS *vps)
+{
+ HevcExtractLayerContext *ctx = bsf->priv_data;
+
+ if (ctx->nuh_layer_id > 0) {
+ if (vps->vps_max_layers_minus1 == 0)
+ av_log(bsf, AV_LOG_ERROR,
+ "vps_max_layers_minus1 is zero, only base layer is
available.\n");
+ else if (ctx->nuh_layer_id > vps->vps_max_layer_id)
+ // It's a known issue that Apple videotoolbox encoder doesn't set
+ // vps_max_layer_id correctly. So this can be a false positive.
+ av_log(bsf, AV_LOG_ERROR, "Specified nuh_layer_id %d is larger
than vps_max_layer_id %d, "
+ "this might leading to empty output\n",
+ ctx->nuh_layer_id, vps->vps_max_layer_id);
+ }
+
+ vps->vps_max_layers_minus1 = 0;
+ vps->vps_max_layer_id = 0;
+ // TODO: update vps_extension to reflect the layer changes, other than
+ // drop it entirely.
+ vps->vps_extension_flag = 0;
+
+ return 0;
+}
+
+static int hevc_update_fragment(AVBSFContext *bsf, AVPacket *pkt,
+ CodedBitstreamFragment *au)
+{
+ HevcExtractLayerContext *ctx = bsf->priv_data;
+ H265RawNALUnitHeader *header;
+ int ret;
+
+ for (int i = 0; i < au->nb_units; i++) {
+ if (au->units[i].type == HEVC_NAL_VPS) {
+ ret = hevc_update_vps(bsf, au->units[i].content);
+ if (ret)
+ return ret;
+ continue;
+ }
+
+ header = au->units[i].content;
+ if (header->nuh_layer_id != ctx->nuh_layer_id) {
+ ff_cbs_delete_unit(au, i);
+ i--;
+ continue;
+ }
+ header->nuh_layer_id = 0;
+ }
+
+ return 0;
+}
+
+static const CBSBSFType hevc_extract_layer_type = {
+ .codec_id = AV_CODEC_ID_HEVC,
+ .fragment_name = "access unit",
+ .unit_name = "NAL unit",
+ .update_fragment = &hevc_update_fragment,
+};
+
+static int hevc_extract_layer_init(AVBSFContext *bsf)
+{
+ return ff_cbs_bsf_generic_init(bsf, &hevc_extract_layer_type);
+}
+
+#define OFFSET(x) offsetof(HevcExtractLayerContext, x)
+#define FLAGS (AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_BSF_PARAM)
+static const AVOption hevc_extract_layer_options[] = {
+ { "nuh_layer_id", "Extract NALUs with the specified nuh_layer_id and
rewrite as base layer",
+ OFFSET(nuh_layer_id), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 62, FLAGS },
+ { NULL }
+};
+
+static const AVClass hevc_extract_layer_class = {
+ .class_name = "hevc_extract_layer_bsf",
+ .item_name = av_default_item_name,
+ .option = hevc_extract_layer_options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+static const enum AVCodecID hevc_extract_layer_codec_ids[] = {
+ AV_CODEC_ID_HEVC, AV_CODEC_ID_NONE,
+};
+
+const FFBitStreamFilter ff_hevc_extract_layer_bsf = {
+ .p.name = "hevc_extract_layer",
+ .p.codec_ids = hevc_extract_layer_codec_ids,
+ .p.priv_class = &hevc_extract_layer_class,
+ .priv_data_size = sizeof(HevcExtractLayerContext),
+ .init = &hevc_extract_layer_init,
+ .close = &ff_cbs_bsf_generic_close,
+ .filter = &ff_cbs_bsf_generic_filter,
+};
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 15f7c3fe3d..dfd3d5d7e5 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -29,8 +29,8 @@
#include "version_major.h"
-#define LIBAVCODEC_VERSION_MINOR 56
-#define LIBAVCODEC_VERSION_MICRO 101
+#define LIBAVCODEC_VERSION_MINOR 57
+#define LIBAVCODEC_VERSION_MICRO 100
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
LIBAVCODEC_VERSION_MINOR, \
--
2.25.1
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