libavformat/mp3enc.c:238: error: Uninitialized Value
  The value read from srate_idx was never initialized.

libavformat/mp3enc.c:238:5: 
236.     header  =  0xff                                  << 24; // sync
237.     header |= (0x7 << 5 | 0x3 << 3 | 0x1 << 1 | 0x1) << 16; // sync/mpeg-1/layer 3/no crc*/
238.     header |= (bitrate_idx << 4 | srate_idx << 2)    <<  8;
         ^
239.     header |= channels << 6;
240.     avio_wb32(s->pb, header);
