>  search some materials, find that the decode method of AFS convolutional
> code is different from the EFS`, it use RSC, and need SOVA(soft output
> viterbi algorithm). am i right?

No.

It _does_ use RSC (and the viterbi code in libosmocore supports RSC).
But that has nothing to do with SOVA and SOVA is _not_ required at
all.

AFAIK, the AMR code I sent a while is correct. Just to be sure I
attached the latest version I have. I haven't tested all the modes but
at least 12.2 and 10.2 should be correct.

Cheers,

    Sylvain