movenc: Don't use track_id to decide which track is the first in a moof

If one track doesn't have any samples within a moof, no traf/trun
is written for it. When the omit_tfhd_offset flag is set, none
of the tfhd atoms have any base_data_offset set, and the implicit
offset (end of previous track fragment data, or start of the moof
for the first trun) is used.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/libavformat/movenc.h b/libavformat/movenc.h
index 2f2c09cbd0..a463a8d527 100644
--- a/libavformat/movenc.h
+++ b/libavformat/movenc.h
@@ -158,6 +158,7 @@ typedef struct MOVMuxContext {
     int max_fragment_size;
     int ism_lookahead;
     AVIOContext *mdat_buf;
+    int first_trun;
 
     int64_t reserved_moov_pos;