HDPVR_RCA_BACK
.audio_input = HDPVR_RCA_BACK,
i->audioset = 1<<HDPVR_RCA_FRONT | 1<<HDPVR_RCA_BACK | 1<<HDPVR_SPDIF;
[HDPVR_RCA_BACK] = "RCA back",