But what old codec are you referring to? If you mean audio via Dolby Digital and DTS, both are lossy compression algorithms. The damage is done the moment the audio engineer feeds the master into the encoder, long before it ends up on a disc that we can drop into a player. Any extra processing done by the surround processor or receiver after decoding (which is technically possible through techniques such as upsampling, none of which have any relationship to the codecs used to compress and then decompress the new lossless audio formats) can only do so much because the original data was discarded by the encoder in the first place. It's the same reason that upscaling DVD's can never truly match a native HD signal - no matter how good the video processor used or how good the original DVD transfer was, it can't equal having the pixels available from the start.