[libav-devel] [PATCH] matroskaenc: Allow chapters to be written in trailer

[John Stebbins]

This allows creation of frame accurate chapter marks from sources like
DVD and BD where the precise chapter location is not known until the
chapter mark has been reached during reading.
---
 libavformat/matroskaenc.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 825e92c..5edaa36 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -103,6 +103,7 @@ typedef struct MatroskaMuxContext {
     int cluster_size_limit;
     int64_t cues_pos;
     int64_t cluster_time_limit;
+    int wrote_chapters;
 } MatroskaMuxContext;
 
 
@@ -710,7 +711,7 @@ static int mkv_write_chapters(AVFormatContext *s)
     AVRational scale = {1, 1E9};
     int i, ret;
 
-    if (!s->nb_chapters)
+    if (!s->nb_chapters || mkv->wrote_chapters)
         return 0;
 
     ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CHAPTERS, 
avio_tell(pb));
@@ -743,6 +744,8 @@ static int mkv_write_chapters(AVFormatContext *s)
     }
     end_ebml_master(pb, editionentry);
     end_ebml_master(pb, chapters);
+
+    mkv->wrote_chapters = 1;
     return 0;
 }
 
@@ -1391,6 +1394,11 @@ static int mkv_write_trailer(AVFormatContext *s)
         end_ebml_master(pb, mkv->cluster);
     }
 
+    if (mkv->mode != MODE_WEBM) {
+        ret = mkv_write_chapters(s);
+        if (ret < 0) return ret;
+    }
+
     if (pb->seekable) {
         if (mkv->cues->num_entries) {
             if (mkv->reserve_cues_space) {
-- 
1.8.3.1

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