[FFmpeg-devel] [PATCH 5/5] lavf/concatdec: implement automatic conversions.
Nicolas George
george at nsup.org
Mon Apr 21 16:42:02 CEST 2014
Signed-off-by: Nicolas George <george at nsup.org>
---
doc/demuxers.texi | 8 +++++
libavformat/concatdec.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 92 insertions(+), 1 deletion(-)
I am not entirely sure about that. Does someone have a pointer to a document
that explains what exactly are the differences between MP4 and AnnexB
formats for H.264. I know it changes the limits of subpackets are detected
(length or start code), but obviously it is not enough, it also does
something with extradata.
diff --git a/doc/demuxers.texi b/doc/demuxers.texi
index f0a14e0..757202a 100644
--- a/doc/demuxers.texi
+++ b/doc/demuxers.texi
@@ -128,6 +128,14 @@ If set to 0, any file name is accepted.
The default is -1, it is equivalent to 1 if the format was automatically
probed and 0 otherwise.
+ at item auto_convert
+If set to 1, try to perform automatic conversions on packet data to make the
+streams concatenable.
+
+Currently, the only conversion is adding the h264_mp4toannexb bitstream
+filter to H.264 streams in MP4 format. This is necessary in particular if
+there are resolution changes.
+
@end table
@section flv
diff --git a/libavformat/concatdec.c b/libavformat/concatdec.c
index 5751d0c..4590dc5 100644
--- a/libavformat/concatdec.c
+++ b/libavformat/concatdec.c
@@ -18,7 +18,9 @@
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
+#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "avformat.h"
@@ -31,6 +33,7 @@ typedef enum ConcatMatchMode {
} ConcatMatchMode;
typedef struct ConcatStream {
+ AVBitStreamFilterContext *bsf;
int out_stream_index;
} ConcatStream;
@@ -51,6 +54,7 @@ typedef struct {
int safe;
int seekable;
ConcatMatchMode stream_match_mode;
+ unsigned auto_convert;
} ConcatContext;
static int concat_probe(AVProbeData *probe)
@@ -150,8 +154,17 @@ static int copy_stream_props(AVStream *st, AVStream *source_st)
{
int ret;
- if (st->codec->codec_id || !source_st->codec->codec_id)
+ if (st->codec->codec_id || !source_st->codec->codec_id) {
+ if (st->codec->extradata_size < source_st->codec->extradata_size) {
+ ret = ff_alloc_extradata(st->codec,
+ source_st->codec->extradata_size);
+ if (ret < 0)
+ return ret;
+ }
+ memcpy(st->codec->extradata, source_st->codec->extradata,
+ source_st->codec->extradata_size);
return 0;
+ }
if ((ret = avcodec_copy_context(st->codec, source_st->codec)) < 0)
return ret;
st->r_frame_rate = source_st->r_frame_rate;
@@ -161,6 +174,27 @@ static int copy_stream_props(AVStream *st, AVStream *source_st)
return 0;
}
+static int detect_stream_specific(AVFormatContext *avf, int idx)
+{
+ ConcatContext *cat = avf->priv_data;
+ AVStream *st = cat->avf->streams[idx];
+ ConcatStream *cs = &cat->cur_file->streams[idx];
+ AVBitStreamFilterContext *bsf;
+
+ if (cat->auto_convert && st->codec->codec_id == AV_CODEC_ID_H264 &&
+ (st->codec->extradata_size < 4 || AV_RB32(st->codec->extradata) != 1)) {
+ av_log(cat->avf, AV_LOG_INFO,
+ "Auto-inserting h264_mp4toannexb bitstream filter\n");
+ if (!(bsf = av_bitstream_filter_init("h264_mp4toannexb"))) {
+ av_log(avf, AV_LOG_ERROR, "h264_mp4toannexb bitstream filter "
+ "required for H.264 streams\n");
+ return AVERROR_BSF_NOT_FOUND;
+ }
+ cs->bsf = bsf;
+ }
+ return 0;
+}
+
static int match_streams_one_to_one(AVFormatContext *avf)
{
ConcatContext *cat = avf->priv_data;
@@ -216,6 +250,8 @@ static int match_streams(AVFormatContext *avf)
if (!map)
return AVERROR(ENOMEM);
cat->cur_file->streams = map;
+ memset(map + cat->cur_file->nb_streams, 0,
+ (cat->avf->nb_streams - cat->cur_file->nb_streams) * sizeof(*map));
for (i = cat->cur_file->nb_streams; i < cat->avf->nb_streams; i++)
map[i].out_stream_index = -1;
@@ -231,6 +267,9 @@ static int match_streams(AVFormatContext *avf)
}
if (ret < 0)
return ret;
+ for (i = cat->cur_file->nb_streams; i < cat->avf->nb_streams; i++)
+ if ((ret = detect_stream_specific(avf, i)) < 0)
+ return ret;
cat->cur_file->nb_streams = cat->avf->nb_streams;
return 0;
}
@@ -390,6 +429,46 @@ static int open_next_file(AVFormatContext *avf)
return open_file(avf, fileno);
}
+static int filter_packet(AVFormatContext *avf, ConcatStream *cs, AVPacket *pkt)
+{
+ AVStream *st = avf->streams[cs->out_stream_index];
+ AVBitStreamFilterContext *bsf;
+ AVPacket pkt2;
+ int ret;
+
+ av_assert0(cs->out_stream_index >= 0);
+ for (bsf = cs->bsf; bsf; bsf = bsf->next) {
+ pkt2 = *pkt;
+ ret = av_bitstream_filter_filter(bsf, st->codec, NULL,
+ &pkt2.data, &pkt2.size,
+ pkt->data, pkt->size,
+ !!(pkt->flags & AV_PKT_FLAG_KEY));
+ if (ret < 0) {
+ av_packet_unref(pkt);
+ return ret;
+ }
+ av_assert0(pkt2.buf);
+ if (ret == 0 && pkt2.data != pkt->data) {
+ if ((ret = av_copy_packet(&pkt2, pkt)) < 0) {
+ av_free(pkt2.data);
+ return ret;
+ }
+ ret = 1;
+ }
+ if (ret > 0) {
+ av_free_packet(pkt);
+ pkt2.buf = av_buffer_create(pkt2.data, pkt2.size,
+ av_buffer_default_free, NULL, 0);
+ if (!pkt2.buf) {
+ av_free(pkt2.data);
+ return AVERROR(ENOMEM);
+ }
+ }
+ *pkt = pkt2;
+ }
+ return 0;
+}
+
static int concat_read_packet(AVFormatContext *avf, AVPacket *pkt)
{
ConcatContext *cat = avf->priv_data;
@@ -418,6 +497,8 @@ static int concat_read_packet(AVFormatContext *avf, AVPacket *pkt)
pkt->stream_index = cs->out_stream_index;
break;
}
+ if ((ret = filter_packet(avf, cs, pkt)))
+ return ret;
delta = av_rescale_q(cat->cur_file->start_time - cat->avf->start_time,
AV_TIME_BASE_Q,
@@ -524,6 +605,8 @@ static int concat_seek(AVFormatContext *avf, int stream,
static const AVOption options[] = {
{ "safe", "enable safe mode",
OFFSET(safe), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, DEC },
+ { "auto_convert", "automatically convert bitstream format",
+ OFFSET(auto_convert), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
{ NULL }
};
--
1.7.10.4
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