mov: parse @PRM and @PRQ metadata tags

These tags describe the product and quicktime library version respectively.
They originate from Adobe Premiere, but also some other programs use them.
Contrary to other tags, they contain 'raw' data which is not to be
interpreted as iso639 or mac strings.

Based on a patch by Peter Ross <pross@xvid.org>.

libavformat/mov.c

@@ -258,8 +258,11 @@ static int mov_read_udta_string(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     uint16_t langcode = 0;
     uint32_t data_type = 0, str_size, str_size_alloc;
     int (*parse)(MOVContext*, AVIOContext*, unsigned, const char*) = NULL;
+    int raw = 0;
 
     switch (atom.type) {
+    case MKTAG( '@','P','R','M'): key = "premiere_version"; raw = 1; break;
+    case MKTAG( '@','P','R','Q'): key = "quicktime_version"; raw = 1; break;
     case MKTAG( 'a','A','R','T'): key = "album_artist";    break;
     case MKTAG( 'c','p','r','t'): key = "copyright"; break;
     case MKTAG( 'd','e','s','c'): key = "description"; break;
@@ -318,7 +321,7 @@ static int mov_read_udta_string(MOVContext *c, AVIOContext *pb, MOVAtom atom)
                 }
             }
         } else return 0;
-    } else if (atom.size > 4 && key && !c->itunes_metadata) {
+    } else if (atom.size > 4 && key && !c->itunes_metadata && !raw) {
         str_size = avio_rb16(pb); // string length
         langcode = avio_rb16(pb);
         ff_mov_lang_to_iso639(langcode, language);
@@ -337,7 +340,7 @@ static int mov_read_udta_string(MOVContext *c, AVIOContext *pb, MOVAtom atom)
         return AVERROR_INVALIDDATA;
 
     // allocate twice as much as worst-case
-    str_size_alloc = str_size * 2;
+    str_size_alloc = raw ? str_size + 1 : str_size * 2;
     str = av_malloc(str_size_alloc);
     if (!str)
         return AVERROR(ENOMEM);
@@ -345,7 +348,7 @@ static int mov_read_udta_string(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     if (parse)
         parse(c, pb, str_size, key);
     else {
-        if (data_type == 3 || (data_type == 0 && (langcode < 0x400 || langcode == 0x7fff))) { // MAC Encoded
+        if (!raw && (data_type == 3 || (data_type == 0 && (langcode < 0x400 || langcode == 0x7fff)))) { // MAC Encoded
             mov_read_mac_string(c, pb, str_size, str, str_size_alloc);
         } else {
             avio_read(pb, str, str_size);