Hi..i am a new user here. As per my knowledge PCM is Pulse Code Modulation and is uncompressed audio. In general you cannot assume PCM is inferior as it can spit out up to 8 channels of audio and much higher bit rates than Dolby Digital . I don't know exactly what TiVo outputs as PCM though but it sounds like it may be more than 2 channels. I think some audiofiles actually prefer to use PCM output from Blu Ray players for example.