* it has been introduced in Libav after our AVERROR_BUG and with a modified value.
*/
#define AVERROR_BUG2 (-MKTAG( 'B','U','G',' '))
+#define AVERROR_UNKNOWN (-MKTAG( 'U','N','K','N')) ///< Unknown error, typically from an external library
/**
* Put a description of the AVERROR code errnum in errbuf.