[libav-devel] [PATCH 08/11] movenc: Support writing multiple trun atoms

[Martin Storsjö]

This is needed if all the data for one track isn't continuous
within the mdat. Normally we make sure all the data for one
track is continuous, but in new cases we will need to have
the samples interleaved.
---
 libavformat/movenc.c |   24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 8f7153a..cd6a0b6 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -2286,18 +2286,19 @@ static uint32_t get_sample_flags(MOVTrack *track, 
MOVIentry *entry)
 }
 
 static int mov_write_trun_tag(AVIOContext *pb, MOVMuxContext *mov,
-                              MOVTrack *track, int moof_size)
+                              MOVTrack *track, int moof_size,
+                              int first, int end)
 {
     int64_t pos = avio_tell(pb);
     uint32_t flags = MOV_TRUN_DATA_OFFSET;
     int i;
 
-    for (i = 0; i < track->entry; i++) {
+    for (i = first; i < end; i++) {
         if (get_cluster_duration(track, i) != track->default_duration)
             flags |= MOV_TRUN_SAMPLE_DURATION;
         if (track->cluster[i].size != track->default_size)
             flags |= MOV_TRUN_SAMPLE_SIZE;
-        if (i > 0 && get_sample_flags(track, &track->cluster[i]) != 
track->default_sample_flags)
+        if (i > first && get_sample_flags(track, &track->cluster[i]) != 
track->default_sample_flags)
             flags |= MOV_TRUN_SAMPLE_FLAGS;
     }
     if (!(flags & MOV_TRUN_SAMPLE_FLAGS))
@@ -2310,18 +2311,18 @@ static int mov_write_trun_tag(AVIOContext *pb, 
MOVMuxContext *mov,
     avio_w8(pb, 0); /* version */
     avio_wb24(pb, flags);
 
-    avio_wb32(pb, track->entry); /* sample count */
+    avio_wb32(pb, end - first); /* sample count */
     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 */
+                      track->cluster[first].pos); /* data offset */
     if (flags & MOV_TRUN_FIRST_SAMPLE_FLAGS)
-        avio_wb32(pb, get_sample_flags(track, &track->cluster[0]));
+        avio_wb32(pb, get_sample_flags(track, &track->cluster[first]));
 
-    for (i = 0; i < track->entry; i++) {
+    for (i = first; i < end; i++) {
         if (flags & MOV_TRUN_SAMPLE_DURATION)
             avio_wb32(pb, get_cluster_duration(track, i));
         if (flags & MOV_TRUN_SAMPLE_SIZE)
@@ -2410,11 +2411,18 @@ static int mov_write_traf_tag(AVIOContext *pb, 
MOVMuxContext *mov,
                               int moof_size)
 {
     int64_t pos = avio_tell(pb);
+    int i, start = 0;
     avio_wb32(pb, 0); /* size placeholder */
     ffio_wfourcc(pb, "traf");
 
     mov_write_tfhd_tag(pb, mov, track, moof_offset);
-    mov_write_trun_tag(pb, mov, track, moof_size);
+    for (i = 1; i < track->entry; i++) {
+        if (track->cluster[i].pos != track->cluster[i - 1].pos + 
track->cluster[i - 1].size) {
+            mov_write_trun_tag(pb, mov, track, moof_size, start, i);
+            start = i;
+        }
+    }
+    mov_write_trun_tag(pb, mov, track, moof_size, start, track->entry);
     if (mov->mode == MODE_ISM) {
         mov_write_tfxd_tag(pb, track);
 
-- 
1.7.9.4

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