This is intended as a replacement for the 'split' function exported by
some parsers.
---
doc/bitstream_filters.texi | 18 +++
libavcodec/Makefile | 1 +
libavcodec/bitstream_filters.c | 1 +
libavcodec/extract_extradata_bsf.c | 300 +++++++++++++++++++++++++++++++++++++
4 files changed, 320 insertions(+)
create mode 100644 libavcodec/extract_extradata_bsf.c
diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
index 6e7f878..e063491 100644
--- a/doc/bitstream_filters.texi
+++ b/doc/bitstream_filters.texi
@@ -21,6 +21,24 @@ Below is a description of the currently available bitstream
filters.
@section dump_extradata
+@section extract_extradata
+
+Extract the in-band extradata.
+
+Certain codecs allow the long-term headers (e.g. MPEG-2 sequence headers,
+or H.264/HEVC (VPS/)SPS/PPS) to be transmitted either "in-band" (i.e. as a part
+of the bitstream containing the coded frames) or "out of band" (e.g. on the
+container level). This latter form is called "extradata" in Libav terminology.
+
+This bitstream filter detects the in-band headers and makes them available as
+extradata.
+
+@table @option
+@item remove
+When this option is enabled, the long-term headers are additionally removed
from
+the bitstream.
+@end table
+
@section h264_mp4toannexb
@section imx_dump_header
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index d4579f9..66a6c66 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -748,6 +748,7 @@ OBJS-$(CONFIG_AAC_ADTSTOASC_BSF) +=
aac_adtstoasc_bsf.o aacadtsdec.o \
mpeg4audio.o
OBJS-$(CONFIG_CHOMP_BSF) += chomp_bsf.o
OBJS-$(CONFIG_DUMP_EXTRADATA_BSF) += dump_extradata_bsf.o
+OBJS-$(CONFIG_EXTRACT_EXTRADATA_BSF) += extract_extradata_bsf.o
OBJS-$(CONFIG_H264_MP4TOANNEXB_BSF) += h264_mp4toannexb_bsf.o
OBJS-$(CONFIG_HEVC_MP4TOANNEXB_BSF) += hevc_mp4toannexb_bsf.o
OBJS-$(CONFIG_IMX_DUMP_HEADER_BSF) += imx_dump_header_bsf.o
diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
index 3b4026c..8a5379e 100644
--- a/libavcodec/bitstream_filters.c
+++ b/libavcodec/bitstream_filters.c
@@ -27,6 +27,7 @@
extern const AVBitStreamFilter ff_aac_adtstoasc_bsf;
extern const AVBitStreamFilter ff_chomp_bsf;
extern const AVBitStreamFilter ff_dump_extradata_bsf;
+extern const AVBitStreamFilter ff_extract_extradata_bsf;
extern const AVBitStreamFilter ff_h264_mp4toannexb_bsf;
extern const AVBitStreamFilter ff_hevc_mp4toannexb_bsf;
extern const AVBitStreamFilter ff_imx_dump_header_bsf;
diff --git a/libavcodec/extract_extradata_bsf.c
b/libavcodec/extract_extradata_bsf.c
new file mode 100644
index 0000000..20b3080
--- /dev/null
+++ b/libavcodec/extract_extradata_bsf.c
@@ -0,0 +1,300 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+
+#include "libavutil/common.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+#include "libavutil/opt.h"
+
+#include "avcodec.h"
+#include "bsf.h"
+#include "h2645_parse.h"
+#include "h264.h"
+#include "hevc.h"
+#include "vc1_common.h"
+
+typedef struct ExtractExtradataContext {
+ const AVClass *class;
+
+ int (*extract)(AVBSFContext *ctx, AVPacket *pkt,
+ uint8_t **data, int *size);
+
+ /* AVOptions */
+ int remove;
+} ExtractExtradataContext;
+
+static int val_in_array(const int *arr, int len, int val)
+{
+ int i;
+ for (i = 0; i < len; i++)
+ if (arr[i] == val)
+ return 1;
+ return 0;
+}
+
+static int extract_extradata_h2645(AVBSFContext *ctx, AVPacket *pkt,
+ uint8_t **data, int *size)
+{
+ static const int extradata_nal_types_hevc[] = {
+ HEVC_NAL_VPS, HEVC_NAL_SPS, HEVC_NAL_PPS,
+ };
+ static const int extradata_nal_types_h264[] = {
+ H264_NAL_SPS, H264_NAL_PPS,
+ };
+
+ ExtractExtradataContext *s = ctx->priv_data;
+
+ H2645Packet h2645_pkt = { 0 };
+ int extradata_size = 0;
+ const int *extradata_nal_types;
+ int nb_extradata_nal_types;
+ int i, ret = 0;
+
+ if (ctx->par_in->codec_id == AV_CODEC_ID_HEVC) {
+ extradata_nal_types = extradata_nal_types_hevc;
+ nb_extradata_nal_types = FF_ARRAY_ELEMS(extradata_nal_types_hevc);
+ } else {
+ extradata_nal_types = extradata_nal_types_h264;
+ nb_extradata_nal_types = FF_ARRAY_ELEMS(extradata_nal_types_h264);
+ }
+
+ ret = ff_h2645_packet_split(&h2645_pkt, pkt->data, pkt->size,
+ ctx, 0, 0, ctx->par_in->codec_id);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < h2645_pkt.nb_nals; i++) {
+ H2645NAL *nal = &h2645_pkt.nals[i];
+ if (val_in_array(extradata_nal_types, nb_extradata_nal_types,
nal->type))
+ extradata_size += nal->raw_size + 3;
+ }
+
+ if (extradata_size) {
+ AVBufferRef *filtered_buf;
+ uint8_t *extradata, *filtered_data;
+
+ if (s->remove) {
+ filtered_buf = av_buffer_alloc(pkt->size +
AV_INPUT_BUFFER_PADDING_SIZE);
+ if (!filtered_buf)
+ goto fail;
+ filtered_data = filtered_buf->data;
+ }
+
+ extradata = av_malloc(extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
+ if (!extradata) {
+ av_buffer_unref(&filtered_buf);
+ goto fail;
+ }
+
+ *data = extradata;
+ *size = extradata_size;
+
+ for (i = 0; i < h2645_pkt.nb_nals; i++) {
+ H2645NAL *nal = &h2645_pkt.nals[i];
+ if (val_in_array(extradata_nal_types, nb_extradata_nal_types,
+ nal->type)) {
+ AV_WB24(extradata, 1); // startcode
+ memcpy(extradata + 3, nal->raw_data, nal->raw_size);
+ extradata += 3 + nal->raw_size;
+ } else if (s->remove) {
+ AV_WB24(filtered_data, 1); // startcode
+ memcpy(filtered_data + 3, nal->raw_data, nal->raw_size);
+ filtered_data += 3 + nal->raw_size;
+ }
+ }
+
+ if (s->remove) {
+ av_buffer_unref(&pkt->buf);
+ pkt->buf = filtered_buf;
+ pkt->data = filtered_buf->data;
+ pkt->size = filtered_data - filtered_buf->data;
+ }
+ }
+
+fail:
+ ff_h2645_packet_uninit(&h2645_pkt);
+ return ret;
+}
+
+static int extract_extradata_vc1(AVBSFContext *ctx, AVPacket *pkt,
+ uint8_t **data, int *size)
+{
+ ExtractExtradataContext *s = ctx->priv_data;
+ uint32_t state = UINT32_MAX;
+ int has_extradata = 0, extradata_size = 0;
+ int i;
+
+ for (i = 0; i < pkt->size; i++) {
+ state = (state << 8) | pkt->data[i];
+ if (IS_MARKER(state)) {
+ if (state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT) {
+ has_extradata = 1;
+ } else if (has_extradata) {
+ extradata_size = i - 3;
+ break;
+ }
+ }
+ }
+
+ if (extradata_size) {
+ *data = av_malloc(extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
+ if (!*data)
+ return AVERROR(ENOMEM);
+
+ memcpy(*data, pkt->data, extradata_size);
+ *size = extradata_size;
+
+ if (s->remove) {
+ pkt->data += extradata_size;
+ pkt->size -= extradata_size;
+ }
+ }
+
+ return 0;
+}
+
+static int extract_extradata_mpeg124(AVBSFContext *ctx, AVPacket *pkt,
+ uint8_t **data, int *size)
+{
+ ExtractExtradataContext *s = ctx->priv_data;
+ int is_mpeg12 = ctx->par_in->codec_id == AV_CODEC_ID_MPEG1VIDEO ||
+ ctx->par_in->codec_id == AV_CODEC_ID_MPEG2VIDEO;
+ uint32_t state = UINT32_MAX;
+ int i;
+
+ for (i = 0; i < pkt->size; i++) {
+ state = (state << 8) | pkt->data[i];
+ if ((is_mpeg12 && state != 0x1B3 && state != 0x1B5 && state < 0x200 &&
state >= 0x100) ||
+ (!is_mpeg12 && (state == 0x1B3 || state == 0x1B6))) {
+ if (i > 3) {
+ *size = i - 3;
+ *data = av_malloc(*size + AV_INPUT_BUFFER_PADDING_SIZE);
+ if (!*data)
+ return AVERROR(ENOMEM);
+
+ memcpy(*data, pkt->data, *size);
+
+ if (s->remove) {
+ pkt->data += *size;
+ pkt->size -= *size;
+ }
+ }
+ break;
+ }
+ }
+ return 0;
+}
+
+static const struct {
+ enum AVCodecID id;
+ int (*extract)(AVBSFContext *ctx, AVPacket *pkt,
+ uint8_t **data, int *size);
+} extract_tab[] = {
+ { AV_CODEC_ID_CAVS, extract_extradata_mpeg124 },
+ { AV_CODEC_ID_H264, extract_extradata_h2645 },
+ { AV_CODEC_ID_HEVC, extract_extradata_h2645 },
+ { AV_CODEC_ID_MPEG1VIDEO, extract_extradata_mpeg124 },
+ { AV_CODEC_ID_MPEG2VIDEO, extract_extradata_mpeg124 },
+ { AV_CODEC_ID_MPEG4, extract_extradata_mpeg124 },
+ { AV_CODEC_ID_VC1, extract_extradata_vc1 },
+};
+
+static int extract_extradata_init(AVBSFContext *ctx)
+{
+ ExtractExtradataContext *s = ctx->priv_data;
+ int i;
+
+ for (i = 0; i < FF_ARRAY_ELEMS(extract_tab); i++) {
+ if (extract_tab[i].id == ctx->par_in->codec_id) {
+ s->extract = extract_tab[i].extract;
+ break;
+ }
+ }
+ if (!s->extract)
+ return AVERROR_BUG;
+
+ return 0;
+}
+
+static int extract_extradata_filter(AVBSFContext *ctx, AVPacket *out)
+{
+ ExtractExtradataContext *s = ctx->priv_data;
+ AVPacket *in;
+ uint8_t *extradata = NULL;
+ int extradata_size;
+ int ret = 0;
+
+ ret = ff_bsf_get_packet(ctx, &in);
+ if (ret < 0)
+ return ret;
+
+ ret = s->extract(ctx, in, &extradata, &extradata_size);
+ if (ret < 0)
+ goto fail;
+
+ if (extradata) {
+ ret = av_packet_add_side_data(in, AV_PKT_DATA_NEW_EXTRADATA,
+ extradata, extradata_size);
+ if (ret < 0) {
+ av_freep(&extradata);
+ goto fail;
+ }
+ }
+
+ av_packet_move_ref(out, in);
+
+fail:
+ av_packet_free(&in);
+ return ret;
+}
+
+static const enum AVCodecID codec_ids[] = {
+ AV_CODEC_ID_CAVS,
+ AV_CODEC_ID_H264,
+ AV_CODEC_ID_HEVC,
+ AV_CODEC_ID_MPEG1VIDEO,
+ AV_CODEC_ID_MPEG2VIDEO,
+ AV_CODEC_ID_MPEG4,
+ AV_CODEC_ID_VC1,
+ AV_CODEC_ID_NONE,
+};
+
+#define OFFSET(x) offsetof(ExtractExtradataContext, x)
+static const AVOption options[] = {
+ { "remove", "remove the extradata from the bitstream", OFFSET(remove),
AV_OPT_TYPE_INT,
+ { .i64 = 0 }, 0, 1 },
+ { NULL },
+};
+
+static const AVClass extract_extradata_class = {
+ .class_name = "extract_extradata",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+const AVBitStreamFilter ff_extract_extradata_bsf = {
+ .name = "extract_extradata",
+ .codec_ids = codec_ids,
+ .priv_data_size = sizeof(ExtractExtradataContext),
+ .priv_class = &extract_extradata_class,
+ .init = extract_extradata_init,
+ .filter = extract_extradata_filter,
+};
--
2.0.0
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