[LAU] new application

We are linux developers with no ALSA experience. We have an application where we want to take 1 to 4 I2s streams, run them through a mixer, and then output them in their original format on the same i2s streams. These i2s streams are from one source but can represent 2-8 channels. These streams can contain PCM (also multi channel PCM), all DTS and Dolby formats up to HD (DTS-HDMA & Dolby True-HD). If there is an off the shelf audio chip we can buy with ALSA support that can do the above, we would like to use it. We might also need to mix in a microphone with ducking support etc... any suggestions would be helpful.