Framework HDMI Missing Sound Output

After watching stuttering 1080p@60 video once too many, I decided to retire my old NUC5i3RYH and switch it with Gen 11 Framework board I had lying around. It was supposed to be a quick swap. Just take SSD from old computer, move it to the new one, place new one into a Cooler Master case, and connect back all the cables. What could go wrong?

Well, everything. First, there was an issue with mounting. NUC uses “sorta” VESA 100mm, Framework uses VESA 100mm, while TV uses VESA 200mm. Thus I assumed I could use NUC’s mounting. Albeit, 200-to-100mm adapter used for NUC was just a fraction too thick for placing Framework screws. So I spent an hour with a dremel making slots slightly thinner. Funny how shaving metal looks awfully like shaving yak.

Well, at least after mounting my case onto TV, there would be no issues. Full of hope, I turned on the computer and … nothing. Gen 11 motherboards have an issue where they would literally destroy their CMOS battery. And then it would refuse to start until battery charges enough. Some time back I fixed that using a soldering mod to use laptop battery instead. However, guess what my newly mounted laptop didn’t have? Yep, Cooler Master case contains no battery. So, coaxing board to power on took another 30 minutes and future order for ML1220 battery.

With system powered on, there was an additional issue lurking. My NUC used mini-HDMI output while Framework provides HDMI via its expansion card. So, that required a trip to the garage and going over all the cables. I am ashamed to say there was not a single 4K@60Hz cable to be found. So, I took the best looking one and tried it out. It actually worked with just a bit of “shimmering”. Downgrading my settings to 4K@30 solved that issue.

And now finally I was able to relax and watch some Starcraft. Notice the use of word “watch” since I definitely noticed there was no sound. After all that, my “new” computer wouldn’t give me a peep. I mean, output was there. And all was connected. But TV didn’t understand that.

And on this I spent ages. First I tried different HDMI expansion cards - since I did a soldering mod on mine, I thought that might be an issue. Then I tried connecting things using analog audio - it took a while to find analog 3.5mm cable and it took much longer banging my head into the wall when I noticed that TV as no analog input. Then I tried bluetooth on my soundbar - that one kinda worked until you switch input on TV when HDMI ARC would take over and bluetooth would turn off. I was half-tempted to leave it like this.

But, in the moment of desperation I though of connecting via bluetooth to my TV and then using existing ARC connection to my soundbar. Unfortunately, it was then when I found out my TV only has bluetooth output and no bluetooth input. Fortunately, search for non-existent bluetooth input settings led me to audio “Expert Settings”. There I saw “HDMI Input Audio Format” setting. With NUC my TV has happy to work in “Bitstream” mode. However, switching this to “PCM” actually made my Framework work properly.

Now, why my TV had Bitstream set? I have no idea. Why NUC was happy to output compressed audio on HDMI while Framework wasn’t? I have no idea. Will I remember this next time I change computer? Definitely not.

After a long day, I did get to watch some Starcraft. So, I guess this can be considered a success.