lavc: add a bitstream filter for extracting extradata from packets

This is intended as a replacement for the 'split' function exported by
some parsers.

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 removed from the
+bitstream after extraction.
+@end table
+
 @section h264_mp4toannexb
 
 @section imx_dump_header

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

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;

libavcodec/extract_extradata_bsf.c

+/*
+ * 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,
+};

libavcodec/version.h

@@ -28,8 +28,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVCODEC_VERSION_MAJOR 57
-#define LIBAVCODEC_VERSION_MINOR 27
-#define LIBAVCODEC_VERSION_MICRO  2
+#define LIBAVCODEC_VERSION_MINOR 28
+#define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \