movenc: Add an option for omitting the tfhd base offset

This makes the output fragments independent of their position in
the output stream, making the output work better when streamed.

QuickTime Player doesn't support fragmented mp4 without the base
data offset, though.

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 16 insertions, 7 deletions

diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 051d6ac280..7d634ad853 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -52,6 +52,7 @@ static const AVOption options[] = {
     { "frag_custom", "Flush fragments on caller requests", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_FRAG_CUSTOM}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
     { "isml", "Create a live smooth streaming feed (for pushing to a publishing point)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_ISML}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
     { "faststart", "Run a second pass to put the index (moov atom) at the beginning of the file", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_FASTSTART}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" },
+    { "omit_tfhd_offset", "Omit the base data offset in tfhd atoms", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_OMIT_TFHD_OFFSET}, 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},
@@ -2212,8 +2213,8 @@ static int mov_write_mfhd_tag(AVIOContext *pb, MOVMuxContext *mov)
     return 0;
 }
 
-static int mov_write_tfhd_tag(AVIOContext *pb, MOVTrack *track,
-                              int64_t moof_offset)
+static int mov_write_tfhd_tag(AVIOContext *pb, MOVMuxContext *mov,
+                              MOVTrack *track, int64_t moof_offset)
 {
     int64_t pos = avio_tell(pb);
     uint32_t flags = MOV_TFHD_DEFAULT_SIZE | MOV_TFHD_DEFAULT_DURATION |
@@ -2223,6 +2224,8 @@ static int mov_write_tfhd_tag(AVIOContext *pb, MOVTrack *track,
     } else {
         flags |= MOV_TFHD_DEFAULT_FLAGS;
     }
+    if (mov->flags & FF_MOV_FLAG_OMIT_TFHD_OFFSET)
+        flags &= ~MOV_TFHD_BASE_DATA_OFFSET;
 
     /* Don't set a default sample size, the silverlight player refuses
      * to play files with that set. Don't set a default sample duration,
@@ -2267,7 +2270,8 @@ static uint32_t get_sample_flags(MOVTrack *track, MOVIentry *entry)
            (MOV_FRAG_SAMPLE_FLAG_DEPENDS_YES | MOV_FRAG_SAMPLE_FLAG_IS_NON_SYNC);
 }
 
-static int mov_write_trun_tag(AVIOContext *pb, MOVTrack *track, int moof_size)
+static int mov_write_trun_tag(AVIOContext *pb, MOVMuxContext *mov,
+                              MOVTrack *track, int moof_size)
 {
     int64_t pos = avio_tell(pb);
     uint32_t flags = MOV_TRUN_DATA_OFFSET;
@@ -2292,8 +2296,13 @@ static int mov_write_trun_tag(AVIOContext *pb, MOVTrack *track, int moof_size)
     avio_wb24(pb, flags);
 
     avio_wb32(pb, track->entry); /* sample count */
-    avio_wb32(pb, moof_size + 8 + track->data_offset +
-                  track->cluster[0].pos); /* data offset */
+    if (mov->flags & FF_MOV_FLAG_OMIT_TFHD_OFFSET &&
+        !(mov->flags & FF_MOV_FLAG_SEPARATE_MOOF) &&
+        track->track_id != 1)
+        avio_wb32(pb, 0); /* Later tracks follow immediately after the previous one */
+    else
+        avio_wb32(pb, moof_size + 8 + track->data_offset +
+                      track->cluster[0].pos); /* data offset */
     if (flags & MOV_TRUN_FIRST_SAMPLE_FLAGS)
         avio_wb32(pb, get_sample_flags(track, &track->cluster[0]));
 
@@ -2389,8 +2398,8 @@ static int mov_write_traf_tag(AVIOContext *pb, MOVMuxContext *mov,
     avio_wb32(pb, 0); /* size placeholder */
     ffio_wfourcc(pb, "traf");
 
-    mov_write_tfhd_tag(pb, track, moof_offset);
-    mov_write_trun_tag(pb, track, moof_size);
+    mov_write_tfhd_tag(pb, mov, track, moof_offset);
+    mov_write_trun_tag(pb, mov, track, moof_size);
     if (mov->mode == MODE_ISM) {
         mov_write_tfxd_tag(pb, track);