avformat/mxfdec: set codec_tag for prores codec

libavformat/mxfdec.c

@@ -2432,6 +2432,18 @@ static int mxf_parse_structural_metadata(MXFContext *mxf)
                 default:
                     av_log(mxf->fc, AV_LOG_INFO, "Unknown frame layout type: %d\n", descriptor->frame_layout);
             }
+
+            if (st->codecpar->codec_id == AV_CODEC_ID_PRORES) {
+                switch (descriptor->essence_codec_ul[14]) {
+                case 1: st->codecpar->codec_tag = MKTAG('a','p','c','o'); break;
+                case 2: st->codecpar->codec_tag = MKTAG('a','p','c','s'); break;
+                case 3: st->codecpar->codec_tag = MKTAG('a','p','c','n'); break;
+                case 4: st->codecpar->codec_tag = MKTAG('a','p','c','h'); break;
+                case 5: st->codecpar->codec_tag = MKTAG('a','p','4','h'); break;
+                case 6: st->codecpar->codec_tag = MKTAG('a','p','4','x'); break;
+                }
+            }
+
             if (st->codecpar->codec_id == AV_CODEC_ID_RAWVIDEO) {
                 st->codecpar->format = descriptor->pix_fmt;
                 if (st->codecpar->format == AV_PIX_FMT_NONE) {