[FFmpeg-devel] [PATCH 24/24] avformat/matroskaenc: Don't implicitly mark WebVTT in WebM as English

[Andreas Rheinhardt]

Writing the language of WebVTT in WebM proceeded differently than the
language of all other tracks: In case no language was given, it does not
write anything instead of "und" (for undefined). Because the default
value of the Language element in WebM (that inherited it from Matroska)
is "eng" (for English), any such track will actually be flagged as
English.

Doing it this way goes back to commit 509642b4 (the commit adding
support for WebVTT) and no reason for this has been given in the commit
message or in the discussion about this patch on the mailing list; the
best I can think of is this: the WebM wiki contains "The srclang attribute
is stored as the Language sub-element." Someone unfamiliar with default
values in Matroska/WebM could interpret this as meaning that no Language
element should be written if there is no srclang attribute. But this is
wrong and this commit changes it.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
 libavformat/matroskaenc.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 83ed43ab77..2331e21ff8 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -1122,11 +1122,8 @@ static int mkv_write_track(AVFormatContext *s, MatroskaMuxContext *mkv,
     if ((tag = av_dict_get(st->metadata, "title", NULL, 0)))
         put_ebml_string(pb, MATROSKA_ID_TRACKNAME, tag->value);
     tag = av_dict_get(st->metadata, "language", NULL, 0);
-    if (mkv->mode != MODE_WEBM || par->codec_id != AV_CODEC_ID_WEBVTT) {
-        put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag && tag->value ? tag->value:"und");
-    } else if (tag && tag->value) {
-        put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag->value);
-    }
+    put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE,
+                    tag && tag->value ? tag->value : "und");
 
     // The default value for TRACKFLAGDEFAULT is 1, so add element
     // if we need to clear it.
-- 
2.20.1