[FFmpeg-devel] [PATCH] avformat/isom: enable extended language for mov

[Yongle Lin]

Allow extended language codes using ISO designation for text tracks in mov format when strictness is set to experimental
---
This patch includes a support for mov format to extend language codes using ISO designation for text tracks(https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/QTFFChap4/qtff4.html#//apple_ref/doc/uid/TP40000939-CH206-27005) and a FATE test associates with it.

 libavformat/isom.c               | 9 +++++++--
 libavformat/isom.h               | 2 +-
 libavformat/movenc.c             | 6 +++---
 tests/fate/mov.mak               | 3 +++
 tests/ref/fate/mov-extended-lang | 4 ++++
 5 files changed, 18 insertions(+), 6 deletions(-)
 create mode 100644 tests/ref/fate/mov-extended-lang

diff --git a/libavformat/isom.c b/libavformat/isom.c
index 44c7b13038..e59d085d16 100644
--- a/libavformat/isom.c
+++ b/libavformat/isom.c
@@ -416,7 +416,7 @@ static const char mov_mdhd_language_map[][4] = {
     "cat", "lat", "que", "grn", "aym", "tat", "uig", "dzo", "jav"
 };
 
-int ff_mov_iso639_to_lang(const char lang[4], int mp4)
+int ff_mov_iso639_to_lang(const char lang[4], int mp4, int strict_std_compliance)
 {
     int i, code = 0;
 
@@ -426,8 +426,13 @@ int ff_mov_iso639_to_lang(const char lang[4], int mp4)
             return i;
     }
     /* XXX:can we do that in mov too? */
-    if (!mp4)
+    if (!mp4 && (strict_std_compliance != FF_COMPLIANCE_EXPERIMENTAL || !strcmp(lang, "und"))) {
+        if (strcmp(lang, "und"))
+            av_log(NULL, AV_LOG_WARNING, "Non macintosh language is discarded for mov\n");
         return -1;
+    }
+    if (!mp4)
+        av_log(NULL, AV_LOG_WARNING, "Experimental behavior: enable extended language in mov\n");
     /* handle undefined as such */
     if (lang[0] == '\0')
         lang = "und";
diff --git a/libavformat/isom.h b/libavformat/isom.h
index 41a9c64c11..9d018ebf1f 100644
--- a/libavformat/isom.h
+++ b/libavformat/isom.h
@@ -43,7 +43,7 @@ extern const AVCodecTag ff_codec_movaudio_tags[];
 extern const AVCodecTag ff_codec_movsubtitle_tags[];
 extern const AVCodecTag ff_codec_movdata_tags[];
 
-int ff_mov_iso639_to_lang(const char lang[4], int mp4);
+int ff_mov_iso639_to_lang(const char lang[4], int mp4, int strict_std_compliance);
 int ff_mov_lang_to_iso639(unsigned code, char to[4]);
 
 struct AVAESCTR;
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 5d8dc4fd5d..d833eba056 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -3429,7 +3429,7 @@ static int mov_write_string_data_tag(AVIOContext *pb, const char *data, int lang
         return size;
     } else {
         if (!lang)
-            lang = ff_mov_iso639_to_lang("und", 1);
+            lang = ff_mov_iso639_to_lang("und", 1, FF_COMPLIANCE_NORMAL);
         avio_wb16(pb, strlen(data)); /* string length */
         avio_wb16(pb, lang);
         avio_write(pb, data, strlen(data));
@@ -3468,7 +3468,7 @@ static AVDictionaryEntry *get_metadata_lang(AVFormatContext *s,
     while ((t2 = av_dict_get(s->metadata, tag2, t2, AV_DICT_IGNORE_SUFFIX))) {
         len2 = strlen(t2->key);
         if (len2 == len + 4 && !strcmp(t->value, t2->value)
-            && (l = ff_mov_iso639_to_lang(&t2->key[len2 - 3], 1)) >= 0) {
+            && (l = ff_mov_iso639_to_lang(&t2->key[len2 - 3], 1, s->strict_std_compliance)) >= 0) {
             *lang = l;
             return t;
         }
@@ -6429,7 +6429,7 @@ static int mov_init(AVFormatContext *s)
 
         track->st  = st;
         track->par = st->codecpar;
-        track->language = ff_mov_iso639_to_lang(lang?lang->value:"und", mov->mode!=MODE_MOV);
+        track->language = ff_mov_iso639_to_lang(lang?lang->value:"und", mov->mode!=MODE_MOV, s->strict_std_compliance);
         if (track->language < 0)
             track->language = 32767;  // Unspecified Macintosh language code
         track->mode = mov->mode;
diff --git a/tests/fate/mov.mak b/tests/fate/mov.mak
index 7a721d7c95..522011b172 100644
--- a/tests/fate/mov.mak
+++ b/tests/fate/mov.mak
@@ -29,6 +29,7 @@ FATE_MOV_FFPROBE = fate-mov-neg-firstpts-discard \
                    fate-mov-guess-delay-2 \
                    fate-mov-guess-delay-3 \
                    fate-mov-mp4-with-mov-in24-ver \
+                   fate-mov-extended-lang \
 
 FATE_MOV_FASTSTART = fate-mov-faststart-4gb-overflow \
 
@@ -124,3 +125,5 @@ fate-mov-faststart-4gb-overflow: CMP = oneline
 fate-mov-faststart-4gb-overflow: REF = bc875921f151871e787c4b4023269b29
 
 fate-mov-mp4-with-mov-in24-ver: CMD = run ffprobe$(PROGSSUF)$(EXESUF) -show_entries stream=codec_name -select_streams 1 $(TARGET_SAMPLES)/mov/mp4-with-mov-in24-ver.mp4
+
+fate-mov-extended-lang: CMD = ffmpeg$(PROGSSUF)$(EXESUF) -f lavfi -i sine=frequency=1000:duration=15 -strict experimental -metadata:s:a:0 language=deu -y $(TARGET_PATH)/metadata.mov; run ffprobe -show_entries stream=index:stream_tags=language $(TARGET_PATH)/metadata.mov; rm metadata.mov
diff --git a/tests/ref/fate/mov-extended-lang b/tests/ref/fate/mov-extended-lang
new file mode 100644
index 0000000000..6d1f61169d
--- /dev/null
+++ b/tests/ref/fate/mov-extended-lang
@@ -0,0 +1,4 @@
+[STREAM]
+index=0
+TAG:language=deu
+[/STREAM]
-- 
2.27.0.278.ge193c7cf3a9-goog