As long as caller only writes packets using av_interleaved_write_frame
with no manual flushing, this should allow us to always have accurate
durations at the end of fragments, since there should be at least
one queued packet in each stream (except for the stream where the
current packet is being written, but if the muxer itself does the
cutting of fragments, it also has info about the next packet for that
stream).
---
This approach was earlier ok'd by Anton.
---
libavformat/avformat.h | 4 ++++
libavformat/internal.h | 10 ++++++++++
libavformat/movenc.c | 22 ++++++++++++++++++++++
libavformat/movenc.h | 1 +
libavformat/mux.c | 11 +++++++++++
libavformat/version.h | 2 +-
6 files changed, 49 insertions(+), 1 deletion(-)
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 7d026b6..fbdfba4 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1720,6 +1720,10 @@ int av_write_frame(AVFormatContext *s, AVPacket *pkt);
* increasing dts. Callers doing their own interleaving should call
* av_write_frame() instead of this function.
*
+ * Using this function instead of av_write_frame() can give muxers advance
+ * knowledge of future packets, improving e.g. the behaviour of the mp4
+ * muxer for VFR content in fragmenting mode.
+ *
* @param s media file handle
* @param pkt The packet containing the data to be written.
* <br>
diff --git a/libavformat/internal.h b/libavformat/internal.h
index 4760ba8..b2a7362 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -441,4 +441,14 @@ static inline int ff_rename(const char *oldpath, const
char *newpath)
*/
void ff_format_io_close(AVFormatContext *s, AVIOContext **pb);
+/**
+ * Find the next packet in the interleaving queue for the given stream.
+ * The packet is not removed from the interleaving queue, but only
+ * a pointer to it is returned.
+ *
+ * @return a pointer to the next packet, or NULL if no packet is queued
+ * for this stream.
+ */
+AVPacket *ff_interleaved_peek(AVFormatContext *s, int stream);
+
#endif /* AVFORMAT_INTERNAL_H */
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 3cbc974..a46d646 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -3188,6 +3188,25 @@ static int mov_flush_fragment(AVFormatContext *s, int
force)
if (!(mov->flags & FF_MOV_FLAG_FRAGMENT))
return 0;
+ // Try to fill in the duration of the last packet in each stream
+ // from queued packets in the interleave queues. If the flushing
+ // of fragments was triggered automatically by an AVPacket, we
+ // already have reliable info for the end of that track, but other
+ // tracks may need to be filled in.
+ for (i = 0; i < s->nb_streams; i++) {
+ MOVTrack *track = &mov->tracks[i];
+ if (!track->end_reliable) {
+ AVPacket *next = ff_interleaved_peek(s, i);
+ if (next) {
+ track->track_duration = next->dts - track->start_dts;
+ if (next->pts != AV_NOPTS_VALUE)
+ track->end_pts = next->pts;
+ else
+ track->end_pts = next->dts;
+ }
+ }
+ }
+
for (i = 0; i < mov->nb_streams; i++) {
MOVTrack *track = &mov->tracks[i];
if (track->entry <= 1)
@@ -3267,6 +3286,7 @@ static int mov_flush_fragment(AVFormatContext *s, int
force)
mov->tracks[i].track_duration -
mov->tracks[i].cluster[0].dts;
mov->tracks[i].entry = 0;
+ mov->tracks[i].end_reliable = 0;
}
avio_flush(s->pb);
return 0;
@@ -3346,6 +3366,7 @@ static int mov_flush_fragment(AVFormatContext *s, int
force)
track->frag_start += duration;
track->entry = 0;
track->entries_flushed = 0;
+ track->end_reliable = 0;
if (!mov->frag_interleave) {
if (!track->mdat_buf)
continue;
@@ -3650,6 +3671,7 @@ static int mov_write_packet(AVFormatContext *s, AVPacket
*pkt)
trk->end_pts = pkt->pts;
else
trk->end_pts = pkt->dts;
+ trk->end_reliable = 1;
mov_auto_flush_fragment(s, 0);
}
}
diff --git a/libavformat/movenc.h b/libavformat/movenc.h
index fccf1f3..6c922fb 100644
--- a/libavformat/movenc.h
+++ b/libavformat/movenc.h
@@ -106,6 +106,7 @@ typedef struct MOVTrack {
int64_t start_dts;
int64_t start_cts;
int64_t end_pts;
+ int end_reliable;
int hint_track; ///< the track that hints this track, -1 if no
hint track is set
int src_track; ///< the track that this hint track describes
diff --git a/libavformat/mux.c b/libavformat/mux.c
index 024e38f..c82c58c 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -614,6 +614,17 @@ int ff_interleave_packet_per_dts(AVFormatContext *s,
AVPacket *out,
}
}
+AVPacket *ff_interleaved_peek(AVFormatContext *s, int stream)
+{
+ AVPacketList *pktl = s->internal->packet_buffer;
+ while (pktl) {
+ if (pktl->pkt.stream_index == stream)
+ return &pktl->pkt;
+ pktl = pktl->next;
+ }
+ return NULL;
+}
+
/**
* Interleave an AVPacket correctly so it can be muxed.
* @param out the interleaved packet will be output here
diff --git a/libavformat/version.h b/libavformat/version.h
index a50e443..09bc29c 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -31,7 +31,7 @@
#define LIBAVFORMAT_VERSION_MAJOR 57
#define LIBAVFORMAT_VERSION_MINOR 6
-#define LIBAVFORMAT_VERSION_MICRO 0
+#define LIBAVFORMAT_VERSION_MICRO 1
#define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
LIBAVFORMAT_VERSION_MINOR, \
--
2.7.4 (Apple Git-66)
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