for(out_i=0; out_i<out->ch_count; out_i++){
switch(s->matrix_ch[out_i][0]){
+ case 0:
+ memset(out->ch[out_i], 0, len * (s->int_sample_fmt == AV_SAMPLE_FMT_FLT ? sizeof(float) : sizeof(int16_t)));
+ break;
case 1:
in_i= s->matrix_ch[out_i][1];
if(mustcopy || s->matrix[out_i][in_i]!=1.0){