libavcodec/adpcm.c:450: error: Uninitialized Value
  The value read from samples_per_byte was never initialized.

libavcodec/adpcm.c:450:9: 
448.             buf_size -= ch;
449.         }
450.         nb_samples += buf_size * samples_per_byte / ch;
             ^
451.         break;
452.     }
