This reduces the need for an edit list; streams that start with
e.g. dts=-1, pts=0 can be encoded as dts=0, pts=0 (which is valid
in mov/mp4) by shifting the dts values of all packets forward.
This avoids the need for edit lists for such streams (while they
still are needed for audio streams with encoder delay).
---
Write iso4 as major brand, properly apply the dts shift when
peeking into the interleaving queue.
---
libavformat/movenc.c | 28 ++++++++++++++++++++++++----
libavformat/movenc.h | 2 ++
2 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 840190d..356d1d6 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -62,6 +62,7 @@ static const AVOption options[] = {
{ "delay_moov", "Delay writing the initial moov until the first fragment
is cut, or until the first fragment flush", 0, AV_OPT_TYPE_CONST, {.i64 =
FF_MOV_FLAG_DELAY_MOOV}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM,
"movflags" },
{ "global_sidx", "Write a global sidx index at the start of the file", 0,
AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_GLOBAL_SIDX}, INT_MIN, INT_MAX,
AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
{ "skip_trailer", "Skip writing the mfra/tfra/mfro trailer for fragmented
files", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_SKIP_TRAILER}, INT_MIN,
INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
+ { "negative_cts_offsets", "Use negative CTS offsets (reducing the need for
edit lists)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_NEGATIVE_CTS_OFFSETS},
INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
FF_RTP_FLAG_OPTS(MOVMuxContext, rtp_flags),
{ "skip_iods", "Skip writing iods atom.", offsetof(MOVMuxContext,
iods_skip), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
{ "iods_audio_profile", "iods audio profile atom.",
offsetof(MOVMuxContext, iods_audio_profile), AV_OPT_TYPE_INT, {.i64 = -1}, -1,
255, AV_OPT_FLAG_ENCODING_PARAM},
@@ -1163,8 +1164,9 @@ static int mov_write_stsd_tag(AVFormatContext *s,
AVIOContext *pb, MOVTrack *tra
return update_size(pb, pos);
}
-static int mov_write_ctts_tag(AVIOContext *pb, MOVTrack *track)
+static int mov_write_ctts_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack
*track)
{
+ MOVMuxContext *mov = s->priv_data;
MOVStts *ctts_entries;
uint32_t entries = 0;
uint32_t atom_size;
@@ -1188,7 +1190,11 @@ static int mov_write_ctts_tag(AVIOContext *pb, MOVTrack
*track)
atom_size = 16 + (entries * 8);
avio_wb32(pb, atom_size); /* size */
ffio_wfourcc(pb, "ctts");
- avio_wb32(pb, 0); /* version & flags */
+ if (mov->flags & FF_MOV_FLAG_NEGATIVE_CTS_OFFSETS)
+ avio_w8(pb, 1); /* version */
+ else
+ avio_w8(pb, 0); /* version */
+ avio_wb24(pb, 0); /* flags */
avio_wb32(pb, entries); /* entry count */
for (i = 0; i < entries; i++) {
avio_wb32(pb, ctts_entries[i].count);
@@ -1273,7 +1279,7 @@ static int mov_write_stbl_tag(AVFormatContext *s,
AVIOContext *pb, MOVTrack *tra
mov_write_stss_tag(pb, track, MOV_PARTIAL_SYNC_SAMPLE);
if (track->par->codec_type == AVMEDIA_TYPE_VIDEO &&
track->flags & MOV_TRACK_CTTS && track->entry)
- mov_write_ctts_tag(pb, track);
+ mov_write_ctts_tag(s, pb, track);
mov_write_stsc_tag(pb, track);
mov_write_stsz_tag(pb, track);
mov_write_stco_tag(pb, track);
@@ -2594,7 +2600,10 @@ static int mov_write_trun_tag(AVIOContext *pb,
MOVMuxContext *mov,
avio_wb32(pb, 0); /* size placeholder */
ffio_wfourcc(pb, "trun");
- avio_w8(pb, 0); /* version */
+ if (mov->flags & FF_MOV_FLAG_NEGATIVE_CTS_OFFSETS)
+ avio_w8(pb, 1); /* version */
+ else
+ avio_w8(pb, 0); /* version */
avio_wb24(pb, flags);
avio_wb32(pb, end - first); /* sample count */
@@ -3040,6 +3049,8 @@ static int mov_write_ftyp_tag(AVIOContext *pb,
AVFormatContext *s)
ffio_wfourcc(pb, "MSNV");
else if (mov->mode == MODE_MP4 && mov->flags &
FF_MOV_FLAG_DEFAULT_BASE_MOOF)
ffio_wfourcc(pb, "iso5"); // Required when using default-base-is-moof
+ else if (mov->mode == MODE_MP4 && mov->flags &
FF_MOV_FLAG_NEGATIVE_CTS_OFFSETS)
+ ffio_wfourcc(pb, "iso4");
else if (mov->mode == MODE_MP4)
ffio_wfourcc(pb, "isom");
else if (mov->mode == MODE_IPOD)
@@ -3288,6 +3299,8 @@ static int mov_flush_fragment(AVFormatContext *s, int
force)
if (!track->end_reliable) {
AVPacket pkt;
if (!ff_interleaved_peek(s, i, &pkt, 1)) {
+ if (track->dts_shift != AV_NOPTS_VALUE)
+ pkt.dts += track->dts_shift;
track->track_duration = pkt.dts - track->start_dts;
if (pkt.pts != AV_NOPTS_VALUE)
track->end_pts = pkt.pts;
@@ -3729,6 +3742,12 @@ static int mov_write_packet(AVFormatContext *s, AVPacket
*pkt)
mov->flags &= ~FF_MOV_FLAG_FRAG_DISCONT;
}
+ if (mov->flags & FF_MOV_FLAG_NEGATIVE_CTS_OFFSETS) {
+ if (trk->dts_shift == AV_NOPTS_VALUE)
+ trk->dts_shift = pkt->pts - pkt->dts;
+ pkt->dts += trk->dts_shift;
+ }
+
if (!pkt->size) {
if (trk->start_dts == AV_NOPTS_VALUE && trk->frag_discont) {
trk->start_dts = pkt->dts;
@@ -4095,6 +4114,7 @@ static int mov_write_header(AVFormatContext *s)
track->start_dts = AV_NOPTS_VALUE;
track->start_cts = AV_NOPTS_VALUE;
track->end_pts = AV_NOPTS_VALUE;
+ track->dts_shift = AV_NOPTS_VALUE;
if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
if (track->tag == MKTAG('m','x','3','p') || track->tag ==
MKTAG('m','x','3','n') ||
track->tag == MKTAG('m','x','4','p') || track->tag ==
MKTAG('m','x','4','n') ||
diff --git a/libavformat/movenc.h b/libavformat/movenc.h
index f4ed188..008f467 100644
--- a/libavformat/movenc.h
+++ b/libavformat/movenc.h
@@ -107,6 +107,7 @@ typedef struct MOVTrack {
int64_t start_cts;
int64_t end_pts;
int end_reliable;
+ int64_t dts_shift;
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
@@ -195,6 +196,7 @@ typedef struct MOVMuxContext {
#define FF_MOV_FLAG_DELAY_MOOV (1 << 13)
#define FF_MOV_FLAG_GLOBAL_SIDX (1 << 14)
#define FF_MOV_FLAG_SKIP_TRAILER (1 << 15)
+#define FF_MOV_FLAG_NEGATIVE_CTS_OFFSETS (1 << 16)
int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt);
--
2.10.1 (Apple Git-78)
_______________________________________________
libav-devel mailing list
[email protected]
https://lists.libav.org/mailman/listinfo/libav-devel
