This solves the problem discussed in
https://ffmpeg.org/pipermail/ffmpeg-devel/2015-September/179238.html
by allowing AVCodec::write_header to be delayed until after packets have been
run through required bitstream filters in order to generate global extradata.
It also provides a mechanism by which a muxer can add a bitstream filter to a
stream automatically, rather than prompting the user to do so.
---
Changelog | 1 +
doc/APIchanges | 3 +++
libavformat/avformat.h | 23 +++++++++++++++++++++++
libavformat/internal.h | 17 +++++++++++++++++
libavformat/mux.c | 47 +++++++++++++++++++++++++++++++++++++++++++++--
libavformat/version.h | 2 +-
6 files changed, 90 insertions(+), 3 deletions(-)
diff --git a/Changelog b/Changelog
index 98927cc..74f1a91 100644
--- a/Changelog
+++ b/Changelog
@@ -37,6 +37,7 @@ version <next>:
- compensationdelay filter
- acompressor filter
- support encoding 16-bit RLE SGI images
+- automatic bitstream filtering
version 2.8:
diff --git a/doc/APIchanges b/doc/APIchanges
index 5b91bb4..eb017d4 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -14,6 +14,9 @@ libavutil: 2015-08-28
API changes, most recent first:
+2015-11-30 - xxxxxxx - lavf 57.20.100 - avformat.h
+ Add automatic bitstream filtering; add av_apply_bitstream_filters()
+
2015-11-29 - xxxxxxx - lavc 57.16.101 - avcodec.h
Deprecate rtp_callback without replacement, i.e. it won't be possible to
get image slices before the full frame is encoded any more. The libavformat
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index d94191e..edbf4cf 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -600,6 +600,29 @@ typedef struct AVOutputFormat {
*/
int (*free_device_capabilities)(struct AVFormatContext *s, struct
AVDeviceCapabilitiesQuery *caps);
enum AVCodecID data_codec; /**< default data codec */
+ /**
+ * Initialize format. May allocate data here, and set any AVFormatContext
or
+ * AVStream parameters that need to be set before packets are sent.
+ * This method must not write output.
+ *
+ * Any allocations made here must be freed in deinit().
+ */
+ int (*init)(struct AVFormatContext *);
+ /**
+ * Deinitialize format. If present, this is called whenever the muxer is
being
+ * destroyed, regardless of whether or not the header has been written.
+ *
+ * If a trailer is being written, this is called after write_trailer().
+ *
+ * This is called if init() fails as well.
+ */
+ void (*deinit)(struct AVFormatContext *);
+ /**
+ * Set up any necessary bitstream filtering and extract any extra data
needed
+ * for the global header.
+ * Return 0 if more packets from this stream must be checked; 1 if not.
+ */
+ int (*check_bitstream)(struct AVFormatContext *, const AVPacket *pkt);
} AVOutputFormat;
/**
* @}
diff --git a/libavformat/internal.h b/libavformat/internal.h
index ee86094..5ed548e 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -117,6 +117,11 @@ struct AVFormatInternal {
int inject_global_side_data;
int avoid_negative_ts_use_pts;
+
+ /**
+ * Whether or not a header has already been written
+ */
+ int header_written;
};
struct AVStreamInternal {
@@ -125,6 +130,18 @@ struct AVStreamInternal {
* from dts.
*/
int reorder;
+
+ /**
+ * bitstream filter to run on stream
+ * - encoding: Set by muxer using ff_stream_add_bitstream_filter
+ * - decoding: unused
+ */
+ AVBitStreamFilterContext *bsfc;
+
+ /**
+ * Whether or not check_bitstream should still be run on each packet
+ */
+ int bitstream_checked;
};
#ifdef __GNUC__
diff --git a/libavformat/mux.c b/libavformat/mux.c
index 05d4170..f3abe0d 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -405,6 +405,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
*options = tmp;
}
+ if (s->oformat->init && (ret = s->oformat->init(s)) < 0) {
+ s->oformat->deinit(s);
+ goto fail;
+ }
+
return 0;
fail:
@@ -456,7 +461,7 @@ int avformat_write_header(AVFormatContext *s, AVDictionary
**options)
if ((ret = init_muxer(s, options)) < 0)
return ret;
- if (s->oformat->write_header) {
+ if (s->oformat->write_header && !s->oformat->check_bitstream) {
ret = s->oformat->write_header(s);
if (ret >= 0 && s->pb && s->pb->error < 0)
ret = s->pb->error;
@@ -464,6 +469,7 @@ int avformat_write_header(AVFormatContext *s, AVDictionary
**options)
return ret;
if (s->flush_packets && s->pb && s->pb->error >= 0 && s->flags &
AVFMT_FLAG_FLUSH_PACKETS)
avio_flush(s->pb);
+ s->internal->header_written = 1;
}
if ((ret = init_pts(s)) < 0)
@@ -1021,6 +1027,17 @@ int av_interleaved_write_frame(AVFormatContext *s,
AVPacket *pkt)
ret = AVERROR(EINVAL);
goto fail;
}
+
+ if (s->oformat->check_bitstream) {
+ if (!st->internal->bitstream_checked) {
+ if ((ret = s->oformat->check_bitstream(s, pkt)) < 0)
+ goto fail;
+ else if (ret == 1)
+ st->internal->bitstream_checked = 1;
+ }
+ }
+
+ av_apply_bitstream_filters(st->codec, pkt, st->internal->bsfc);
} else {
av_log(s, AV_LOG_TRACE, "av_interleaved_write_frame FLUSH\n");
flush = 1;
@@ -1037,10 +1054,22 @@ int av_interleaved_write_frame(AVFormatContext *s,
AVPacket *pkt)
if (ret <= 0) //FIXME cleanup needed for ret<0 ?
return ret;
+ if (!s->internal->header_written && s->oformat->write_header) {
+ ret = s->oformat->write_header(s);
+ if (ret >= 0 && s->pb && s->pb->error < 0)
+ ret = s->pb->error;
+ if (ret < 0)
+ goto fail2;
+ if (s->flush_packets && s->pb && s->pb->error >= 0 && s->flags &
AVFMT_FLAG_FLUSH_PACKETS)
+ avio_flush(s->pb);
+ s->internal->header_written = 1;
+ }
+
ret = write_packet(s, &opkt);
if (ret >= 0)
s->streams[opkt.stream_index]->nb_frames++;
+fail2:
av_packet_unref(&opkt);
if (ret < 0)
@@ -1077,14 +1106,28 @@ int av_write_trailer(AVFormatContext *s)
goto fail;
}
+ if (!s->internal->header_written && s->oformat->write_header) {
+ ret = s->oformat->write_header(s);
+ if (ret >= 0 && s->pb && s->pb->error < 0)
+ ret = s->pb->error;
+ if (ret < 0)
+ goto fail;
+ if (s->flush_packets && s->pb && s->pb->error >= 0 && s->flags &
AVFMT_FLAG_FLUSH_PACKETS)
+ avio_flush(s->pb);
+ s->internal->header_written = 1;
+ }
+
fail:
- if (s->oformat->write_trailer)
+ if ((s->internal->header_written || !s->oformat->write_header) &&
s->oformat->write_trailer)
if (ret >= 0) {
ret = s->oformat->write_trailer(s);
} else {
s->oformat->write_trailer(s);
}
+ if (s->oformat->deinit)
+ s->oformat->deinit(s);
+
if (s->pb)
avio_flush(s->pb);
if (ret == 0)
diff --git a/libavformat/version.h b/libavformat/version.h
index 99ae17d..7a4e61c 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,7 +30,7 @@
#include "libavutil/version.h"
#define LIBAVFORMAT_VERSION_MAJOR 57
-#define LIBAVFORMAT_VERSION_MINOR 19
+#define LIBAVFORMAT_VERSION_MINOR 20
#define LIBAVFORMAT_VERSION_MICRO 100
#define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
--
2.6.3
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