avformat/mpegts: DVB subtitles multiple languages support

Copy multiple languages data from PMT to extradata. New 5 bytes
per language extradata format.
Reviewed-by: Marton Balint <cus@passwd.hu>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/mpegts.c

@@ -1512,31 +1512,69 @@ int ff_parse_mpeg2_descriptor(AVFormatContext *fc, AVStream *st, int stream_type
         }
         break;
     case 0x59: /* subtitling descriptor */
-        language[0] = get8(pp, desc_end);
-        language[1] = get8(pp, desc_end);
-        language[2] = get8(pp, desc_end);
-        language[3] = 0;
-        /* hearing impaired subtitles detection */
-        switch(get8(pp, desc_end)) {
-        case 0x20: /* DVB subtitles (for the hard of hearing) with no monitor aspect ratio criticality */
-        case 0x21: /* DVB subtitles (for the hard of hearing) for display on 4:3 aspect ratio monitor */
-        case 0x22: /* DVB subtitles (for the hard of hearing) for display on 16:9 aspect ratio monitor */
-        case 0x23: /* DVB subtitles (for the hard of hearing) for display on 2.21:1 aspect ratio monitor */
-        case 0x24: /* DVB subtitles (for the hard of hearing) for display on a high definition monitor */
-        case 0x25: /* DVB subtitles (for the hard of hearing) with plano-stereoscopic disparity for display on a high definition monitor */
-            st->disposition |= AV_DISPOSITION_HEARING_IMPAIRED;
-            break;
-        }
-        if (st->codec->extradata) {
-            if (st->codec->extradata_size == 4 && memcmp(st->codec->extradata, *pp, 4))
-                avpriv_request_sample(fc, "DVB sub with multiple IDs");
-        } else {
-            if (!ff_alloc_extradata(st->codec, 4)) {
-                memcpy(st->codec->extradata, *pp, 4);
+        {
+            /* 8 bytes per DVB subtitle substream data:
+             * ISO_639_language_code (3 bytes),
+             * subtitling_type (1 byte),
+             * composition_page_id (2 bytes),
+             * ancillary_page_id (2 bytes) */
+            int language_count = desc_len / 8;
+
+            if (desc_len > 0 && desc_len % 8 != 0)
+                return AVERROR_INVALIDDATA;
+
+            if (language_count > 1) {
+                avpriv_request_sample(fc, "DVB subtitles with multiple languages");
+            }
+
+            if (language_count > 0) {
+                uint8_t *extradata;
+
+                /* 4 bytes per language code (3 bytes) with comma or NUL byte should fit language buffer */
+                if (language_count > sizeof(language) / 4) {
+                    language_count = sizeof(language) / 4;
+                }
+
+                if (st->codec->extradata == NULL) {
+                    if (ff_alloc_extradata(st->codec, language_count * 5)) {
+                        return AVERROR(ENOMEM);
+                    }
+                }
+
+                if (st->codec->extradata_size < language_count * 5)
+                    return AVERROR_INVALIDDATA;
+
+                extradata = st->codec->extradata;
+
+                for (i = 0; i < language_count; i++) {
+                    language[i * 4 + 0] = get8(pp, desc_end);
+                    language[i * 4 + 1] = get8(pp, desc_end);
+                    language[i * 4 + 2] = get8(pp, desc_end);
+                    language[i * 4 + 3] = ',';
+
+                    /* hearing impaired subtitles detection using subtitling_type */
+                    switch(*pp[0]) {
+                    case 0x20: /* DVB subtitles (for the hard of hearing) with no monitor aspect ratio criticality */
+                    case 0x21: /* DVB subtitles (for the hard of hearing) for display on 4:3 aspect ratio monitor */
+                    case 0x22: /* DVB subtitles (for the hard of hearing) for display on 16:9 aspect ratio monitor */
+                    case 0x23: /* DVB subtitles (for the hard of hearing) for display on 2.21:1 aspect ratio monitor */
+                    case 0x24: /* DVB subtitles (for the hard of hearing) for display on a high definition monitor */
+                    case 0x25: /* DVB subtitles (for the hard of hearing) with plano-stereoscopic disparity for display on a high definition monitor */
+                        st->disposition |= AV_DISPOSITION_HEARING_IMPAIRED;
+                        break;
+                    }
+
+                    extradata[4] = get8(pp, desc_end); /* subtitling_type */
+                    memcpy(extradata, *pp, 4); /* composition_page_id and ancillary_page_id */
+                    extradata += 5;
+
+                    *pp += 4;
+                }
+
+                language[i * 4 - 1] = 0;
+                av_dict_set(&st->metadata, "language", language, 0);
             }
         }
-        *pp += 4;
-        av_dict_set(&st->metadata, "language", language, 0);
         break;
     case 0x0a: /* ISO 639 language descriptor */
         for (i = 0; i + 4 <= desc_len; i += 4) {

libavformat/version.h

@@ -31,7 +31,7 @@
 
 #define LIBAVFORMAT_VERSION_MAJOR 55
 #define LIBAVFORMAT_VERSION_MINOR 32
-#define LIBAVFORMAT_VERSION_MICRO 100
+#define LIBAVFORMAT_VERSION_MICRO 101
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \