Handle ID3v1 tag while decoding mp[123] frames

patch by Clément Bœsch (ubitux at gmail)

Originally committed as revision 26297 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpegaudiodec.c

@@ -27,6 +27,7 @@
 #include "avcodec.h"
 #include "get_bits.h"
 #include "dsputil.h"
+#include "libavformat/id3v1.h"
 
 /*
  * TODO:
@@ -2043,6 +2044,13 @@ static int decode_frame(AVCodecContext * avctx,
 
     header = AV_RB32(buf);
     if(ff_mpa_check_header(header) < 0){
+
+        if (buf_size == ID3v1_TAG_SIZE
+            && buf[0] == 'T' && buf[1] == 'A' && buf[2] == 'G') {
+            *data_size = 0;
+            return ID3v1_TAG_SIZE;
+        }
+
         av_log(avctx, AV_LOG_ERROR, "Header missing\n");
         return -1;
     }