movenc: Add an option for enabling negative CTS offsets

[ffmpeg] / libavformat / movenc.c

diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 840190dbfa906237ff15160df25793a52c304597..356d1d6b717d854741ac2392bb699a20b9cc19cc 100644 (file)
--- 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') ||