The CS 497xx chips will be a significant improvement over the current 495xx and 494xx series and the older 493xx and prior series. Big step up in MIPS available so that they can do all the new codecs and many other improvements.

Designers have a choice these days between Cirrus, TI, Analog Devices and Freescale (formerly Motorola's semiconductor division). Each of the four takes a slightly different approach such that one isn't necessarily better than the other, but rather each has it's strong points and issues.

All communicate via I2S with the outputs of the HDMI Rx chips and that is how the signals get from the source to the DSP when HDMI used. In theory, there is no reason why you couldn't use the earlier chips with HDMI, but you wouldn't want to since the chips don't have te power to deal with the new codecs; it's the processing requirements, not the communications links.