[0:a:0]pan=mono|c0=c0[mono];
[0:a:0]pan=stereo|c0=c0|c1=c0[stereo];
[0:a:0]pan=2.1|c0=c0|c1=c0|c2=c0[2.1];
[0:a:0]pan=5.1|c0=c0|c1=c0|c2=c0|c3=c0|c4=c0|c5=c0[5.1];
[0:a:0]pan=7.1|c0=c0|c1=c0|c2=c0|c3=c0|c4=c0|c5=c0|c6=c0|c7=c0[7.1];