avcodec/xiph: Return better error codes

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/xiph.c

@@ -35,7 +35,7 @@ int avpriv_split_xiph_headers(const uint8_t *extradata, int extradata_size,
             header_start[i] = extradata;
             extradata += header_len[i];
             if (overall_len > extradata_size - header_len[i])
-                return -1;
+                return AVERROR_INVALIDDATA;
             overall_len += header_len[i];
         }
     } else if (extradata_size >= 3 && extradata_size < INT_MAX - 0x1ff && extradata[0] == 2) {
@@ -50,7 +50,7 @@ int avpriv_split_xiph_headers(const uint8_t *extradata, int extradata_size,
             header_len[i] += *extradata;
             overall_len   += *extradata;
             if (overall_len > extradata_size)
-                return -1;
+                return AVERROR_INVALIDDATA;
         }
         header_len[2] = extradata_size - overall_len;
         header_start[0] = extradata;