libavcodec/metasound.c:310: error: Uninitialized Value
  The value read from isampf was never initialized.

libavcodec/metasound.c:310:5: 
308. 
309.     switch ((avctx->channels << 16) + (isampf << 8) + ibps) {
310.     case (1 << 16) + ( 8 << 8) +  6:
         ^
311.         tctx->mtab = &ff_metasound_mode0806;
312.         break;
