Sanity check number of channels in setup.
Fixes
@@ -684,6 +684,7 @@ int vorbis_encode_setup_init(vorbis_info *vi){
highlevel_encode_setup *hi=&ci->hi;
if(ci==NULL)return(OV_EINVAL);
+ if(vi->channels<1||vi->channels>255)return(OV_EINVAL);
if(!hi->impulse_block_p)i0=1;
/* too low/high an ATH floater is nonsensical, but doesn't break anything */
