avformat/matroskaenc: Allow to set multiple streams as default

The Matroska specifications have evolved and now allow to mark
multiple tracks of the same kind as default (whether this was legal or
not before was dubious; e.g. mkvmerge disallowed it). Yet when the
Matroska muxer is set to infer default dispositions if absent, it also
enforced the now outdated restriction. So update this.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 6 insertions, 10 deletions

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 899a3388cd..e2d9159e2c 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -1395,7 +1395,8 @@ static int mkv_write_tracks(AVFormatContext *s)
 {
     MatroskaMuxContext *mkv = s->priv_data;
     AVIOContext *pb = s->pb;
-    int i, ret, video_default_idx, audio_default_idx, subtitle_default_idx;
+    int video_default_idx = -1, audio_default_idx = -1, subtitle_default_idx = -1;
+    int i, ret;
 
     if (mkv->nb_attachments == s->nb_streams)
         return 0;
@@ -1405,11 +1406,7 @@ static int mkv_write_tracks(AVFormatContext *s)
         return ret;
 
     if (mkv->default_mode != DEFAULT_MODE_PASSTHROUGH) {
-        int video_idx, audio_idx, subtitle_idx;
-
-        video_idx    = video_default_idx    =
-        audio_idx    = audio_default_idx    =
-        subtitle_idx = subtitle_default_idx = -1;
+        int video_idx = -1, audio_idx = -1, subtitle_idx = -1;
 
         for (i = s->nb_streams - 1; i >= 0; i--) {
             AVStream *st = s->streams[i];
@@ -1435,8 +1432,7 @@ static int mkv_write_tracks(AVFormatContext *s)
     }
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];
-        int is_default = mkv->default_mode == DEFAULT_MODE_PASSTHROUGH ?
-                             st->disposition & AV_DISPOSITION_DEFAULT  :
+        int is_default = st->disposition & AV_DISPOSITION_DEFAULT ||
                              i == video_default_idx || i == audio_default_idx ||
                              i == subtitle_default_idx;
         ret = mkv_write_track(s, mkv, st, &mkv->tracks[i],
@@ -2823,8 +2819,8 @@ static const AVOption options[] = {
     { "flipped_raw_rgb", "Raw RGB bitmaps in VFW mode are stored bottom-up", OFFSET(flipped_raw_rgb), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
     { "write_crc32", "write a CRC32 element inside every Level 1 element", OFFSET(write_crc), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, FLAGS },
     { "default_mode", "Controls how a track's FlagDefault is inferred", OFFSET(default_mode), AV_OPT_TYPE_INT, { .i64 = DEFAULT_MODE_INFER }, DEFAULT_MODE_INFER, DEFAULT_MODE_PASSTHROUGH, FLAGS, "default_mode" },
-    { "infer", "For each track type, mark the first track of disposition default as default; if none exists, mark the first track as default.", 0, AV_OPT_TYPE_CONST, { .i64 = DEFAULT_MODE_INFER }, 0, 0, FLAGS, "default_mode" },
-    { "infer_no_subs", "For each track type, mark the first track of disposition default as default; for audio and video: if none exists, mark the first track as default.", 0, AV_OPT_TYPE_CONST, { .i64 = DEFAULT_MODE_INFER_NO_SUBS }, 0, 0, FLAGS, "default_mode" },
+    { "infer", "For each track type, mark each track of disposition default as default; if none exists, mark the first track as default.", 0, AV_OPT_TYPE_CONST, { .i64 = DEFAULT_MODE_INFER }, 0, 0, FLAGS, "default_mode" },
+    { "infer_no_subs", "For each track type, mark each track of disposition default as default; for audio and video: if none exists, mark the first track as default.", 0, AV_OPT_TYPE_CONST, { .i64 = DEFAULT_MODE_INFER_NO_SUBS }, 0, 0, FLAGS, "default_mode" },
     { "passthrough", "Use the disposition flag as-is", 0, AV_OPT_TYPE_CONST, { .i64 = DEFAULT_MODE_PASSTHROUGH }, 0, 0, FLAGS, "default_mode" },
     { NULL },
 };