avformat/xwma: return always proper error codes

libavformat/xwma.c

@@ -60,16 +60,16 @@ static int xwma_read_header(AVFormatContext *s)
     /* check RIFF header */
     tag = avio_rl32(pb);
     if (tag != MKTAG('R', 'I', 'F', 'F'))
-        return -1;
+        return AVERROR_INVALIDDATA;
     avio_rl32(pb); /* file size */
     tag = avio_rl32(pb);
     if (tag != MKTAG('X', 'W', 'M', 'A'))
-        return -1;
+        return AVERROR_INVALIDDATA;
 
     /* parse fmt header */
     tag = avio_rl32(pb);
     if (tag != MKTAG('f', 'm', 't', ' '))
-        return -1;
+        return AVERROR_INVALIDDATA;
     size = avio_rl32(pb);
     st = avformat_new_stream(s, NULL);
     if (!st)