Extend description for AVERROR_INVALIDDATA.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@22600 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavutil/error.h

@@ -46,7 +46,7 @@
 #endif
 
 #define AVERROR_EOF         AVERROR(EPIPE)   /**< End of file. */
-#define AVERROR_INVALIDDATA AVERROR(EINVAL)  /**< invalid data found */
+#define AVERROR_INVALIDDATA AVERROR(EINVAL)  /**< Invalid data found when processing input */
 #define AVERROR_NOFMT       AVERROR(EILSEQ)  /**< unknown format */
 #define AVERROR_NOTSUPP     AVERROR(ENOSYS)  /**< Operation not supported. */