lavf/movenc: Fail when codec tag is invalid for format

Fixes ticket #6897
Signed-off-by: James Almer <jamrial@gmail.com>

libavformat/movenc.c

@@ -1535,9 +1535,9 @@ static int mov_get_rawvideo_codec_tag(AVFormatContext *s, MOVTrack *track)
     return tag;
 }
 
-static int mov_get_codec_tag(AVFormatContext *s, MOVTrack *track)
+static unsigned int mov_get_codec_tag(AVFormatContext *s, MOVTrack *track)
 {
-    int tag = track->par->codec_tag;
+    unsigned int tag = track->par->codec_tag;
 
     if (!tag || (s->strict_std_compliance >= FF_COMPLIANCE_NORMAL &&
                  (track->par->codec_id == AV_CODEC_ID_DVVIDEO ||
@@ -1589,31 +1589,45 @@ static const AVCodecTag codec_cover_image_tags[] = {
     { AV_CODEC_ID_NONE, 0 },
 };
 
-static int mov_find_codec_tag(AVFormatContext *s, MOVTrack *track)
+static unsigned int validate_codec_tag(const AVCodecTag *const *tags,
+                                       unsigned int tag, int codec_id)
 {
-    int tag;
+    int i;
+
+    /**
+     * Check that tag + id is in the table
+     */
+    for (i = 0; tags && tags[i]; i++) {
+        const AVCodecTag *codec_tags = tags[i];
+        while (codec_tags->id != AV_CODEC_ID_NONE) {
+            if (avpriv_toupper4(codec_tags->tag) == avpriv_toupper4(tag) &&
+                codec_tags->id == codec_id)
+                return codec_tags->tag;
+            codec_tags++;
+        }
+    }
+    return 0;
+}
+
+static unsigned int mov_find_codec_tag(AVFormatContext *s, MOVTrack *track)
+{
+    unsigned int tag;
 
     if (is_cover_image(track->st))
         return ff_codec_get_tag(codec_cover_image_tags, track->par->codec_id);
 
-    if (track->mode == MODE_MP4 || track->mode == MODE_PSP)
-        tag = track->par->codec_tag;
-    else if (track->mode == MODE_ISM)
-        tag = track->par->codec_tag;
-    else if (track->mode == MODE_IPOD) {
+    if (track->mode == MODE_IPOD)
         if (!av_match_ext(s->url, "m4a") &&
             !av_match_ext(s->url, "m4v") &&
             !av_match_ext(s->url, "m4b"))
             av_log(s, AV_LOG_WARNING, "Warning, extension is not .m4a nor .m4v "
                    "Quicktime/Ipod might not play the file\n");
-        tag = track->par->codec_tag;
-    } else if (track->mode & MODE_3GP)
-        tag = track->par->codec_tag;
-    else if (track->mode == MODE_F4V)
-        tag = track->par->codec_tag;
-    else
-        tag = mov_get_codec_tag(s, track);
 
+    if (track->mode == MODE_MOV)
+        tag = mov_get_codec_tag(s, track);
+    else
+        tag = validate_codec_tag(s->oformat->codec_tag, track->par->codec_tag,
+                                 track->par->codec_id);
     return tag;
 }