I am currently working on a project using the HiFi Berry DAC+DSP, and my idea is that I want to create a TV volume normalizer so that the annoyingly loud TV ads aren't so bothersome anymore.
The problem here is that I currently have various TVs set up with HDMI over Cat6 extenders so that I may duplicate a Satellite TV signal onto various TVs.
I want to create an external volume normalizer with the HiFiBerry but if I only make use of the Satellite Receiver's (Set-top-box) SPDIF output then the volume normalization would only affect the main TV.
For my setup to affect all TVs I would need to extract audio from the HDMI output on the satellite receiver and then normalize it, then send it to all the TVs, i.e. local TV and remote TVs via ethernet extenders.
So what I was thinking is, since you guys seem to promote in-home room-to-room audio project so much on the main website, maybe it would be cool to have a sound card with an HDMI input [audio extractor] (with video passthrough), which outputs to HDMI but with embedded/inserted processed audio, as set via HiFiBerryOS or whatever interface is necessary to use.
Otherwise, I have to buy like 10 1-foot HDMI cables a bunch of HDMI splitters. It turns into a real mess really fast. An audio extractor alone is like 30 dollars, an audio inserter/embedder is 30. Implementing all this circuitry into a tiny RPI addon would be life-saving.