Fix Hdmi-Cec Weirdness with a Raspberry Pi and a $7 Cable
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The eternal quest for a seamless home entertainment experience just got a little easier, thanks to a clever hack using a Raspberry Pi and a $7 cable to tame HDMI-CEC weirdness. Commenters are buzzing with enthusiasm, sharing their own struggles and triumphs with CEC compatibility, from AppleTV's reliable implementation to the PS4 Pro's lackluster efforts. While some are nostalgic for Logitech's Harmony remote, others are exploring DIY alternatives, like decoding infrared signals with an IR transceiver. As one commenter poignantly put it, the Harmony remote's potential demise is a worrying prospect for many.
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That said props for actually using HDMI-CEC! And it’s cheaper than most smart plugs (and probably safer, too)
> My first instinct was to lean on traditional automation stacks: HomeKit scenes to chain “TV on” into “receiver on” or wattage triggers via an Eve Energy plug. This kind of worked, but every extra layer added 30 seconds of lag or more.
(To be clear, they still work today if you can get a second hand remote / hub.)
I will use Harmony for my home setup until it no longer functions.
The horrors I have seen related to CEC and ARC are something else.
https://www.athom.tech/blank-1/tasmota-ir-controller
I really REALLY want someone to manufacture the thin harmony RF remote with a simple receiver puck with an open firmware. That's all we'd need because the HA crowd would be all over it and have it doing anything you want.
And I, too, will be particularly unhappy when Logitech finally pulls the plug on the servers.
At that point, I'll definitely need something different.
But IR codes are only part of the puzzle. And that is perhaps the easiest part to solve: We've already got lots of databases with IR-stuff available. There's databases focused on RC5, and the sleepy LIRC project, and some other things (all of which tend to be very Old Web in appearance).
License-permitting, it's simple enough to use this work as a foundation onto which newer codes can be placed.
That just leaves making the Harmony hardware interface work (hah, hahah -- and it's a dead-end anyway), or developing a new open-source remote to rule them all (which actually might not be too terrible of a task).
That all covers the first 90% of the problem.
The remaining 90% of the problem is just creating software that has a usable UI and actually works.
(I've tried updating the AppleTV, replugging the HDMI cable, unplugging the HDMI cable for <period of time>, etc. Nothing has worked. TV does not have any network which means it can't have had any nefarious updates.)
Once it's awake the LG remote is passed through to it but I still have to keep the Apple remote around for that first step.
(I was sad at having to give up my nice PS4 universal remote, and not finding an equivalent for the PS5.)
However, I couldn't find a button on the remote that was the equivalent of pressing a PS5 controller's PS Button, and that's pretty important to the messy PS5 UI. But the TV had menus that could simulate pressing that button. So I upgraded to a Sony RM-VLZ620, which added programmable macro buttons, which I kludged hard to navigate that TV menu. From my notes:
The Deck can pretty consistently turn the TV on from standby(/picture mode) and grab the input, but if the TV is completely off (black screen) CEC doesn't work anymore.
Version 1.0 and later of the HDMI spec even mandate that you have to connect those pins across all HDMI ports on your device even if you don't do anything with them.
I wonder if a malfunction in this process is responsible for my AVR sometimes auto-switching to the wrong source.
Better hurry befor-, too late it’s cloned in china
Side note: Sometimes the TV doesn't come on when you press its power button. After a tremendous amount of experimentation, I determined this was because the "brain" was on, but the backlight was not. Power cycling it blind usually fixes it. That's harder than it sounds though because you have to navigate the menu blind using short and long button presses with the one button. But I'm scared to try a new TV, because then I'm going to have to figure out how to get audio out of the TV.
It seems like AV stuff used to be so simple. Now the simplest scenarios seem to require more and more knowledge about arcane connection standard interactions and network topology. Ugh.
You can have bookshelf speakers with an integrated amplifier and HDMI-ARC. All you need is an HDMI cable between the TV and the speakers.
There's also the compact, simple alternatives to bulky receivers that are becoming available: Wiim amp, Sonos amp, Eversolo play, and the cheaper chinese makers like SMSL and Fosi. Each of those brands has a small device the size of an apple tv that will take an HDMI Arc input, and output an amplified signal to power some passive bookshelf speakers.
Also, I collect a lot of old receivers and speakers. It's really not that complicated and the basics have been the same since the 70s and 80s. Any flatscreen TV made in the past 20 years typically has a TOSLINK output which will be compatible with receivers stretching back to the 80s - I have my LG C1 connected to some 90s Marantz receiver this way. Any old receiver you find on Facebook Marketplace for $20 will typically suffice here as long as you check for the TOSLINK port first, but you do need a separate actual amplifier somewhere along the line to drive a speaker larger than a pair of headphones unless the speaker has its own amp built-in.
I find all this stuff fun so my own setup has that chained to a series of other receivers acting as subwoofer amplifiers as well as using the pre-amp output to drive a Mesa Baron tube amplifier/Acoustat electrostats I was gifted, but most people don't need anything so complex.
1. A decoder with at least 5.1 output since that's how many speakers I have
2. At least 3 HDMI inputs + 1 HDMI output to my TV
3. An amplifier with a volume control
That's it! I don't need an FM tuner. I don't need multiple zones. I don't need wild listening modes and DSP effects. I don't need an on-TV setup display. I don't need fiber optic digital audio inputs. I don't need fucking 20 RCA jack inputs composite video, component video, S-Video. You'd think I could find a small cheap box the size of an AppleTV that I could just hide somewhere that could do this, but I couldn't find anything sufficient. So I got another $20 gigantic old receiver again from Craigslist and just leave all those features and inputs unused.
I've got a great sounding 5.1 system with a receiver and a game console and everything set up. You know where it is? My garage.
> So many problems and more money could solve every one of them!
More money isn't going to bring him the right woman. They'll more likely attract an even worse type of woman.
https://www.snapav.com/shop/en/snapav/episode-mini-51-avr-ea...
the only way it could have a smaller back-panel and all of your requirements would be to eliminate the ethernet connector.
Sonos makes this specifically. Has an RCA and HDMI input, along with being a Sonos device for streaming audio.
The only downside is the price.
I had a houseful of overpriced speakers, some only 3 years old when they decided they were too old to support in their rewritten app, or some lazy crap like that.
For GP; I use some cheapo (sub $50) "100W mini amps" from Amazon. They seem fine to me.
1: https://news.ycombinator.com/item?id=42683753
2: https://news.ycombinator.com/item?id=21895086
https://www.marantz.com/en-ca/category/av-separates/
The output of these units is line-level signals feeding high-impedance loads. They could definitely be a fraction of the size they are.
S.M.S.L. make some good ones: https://www.smsl-audio.com/portal/product/index
I use their AD-18 and really love it: https://www.smsl-audio.com/portal/product/detail/id/566.html
I use their AD-18 and really love it: https://www.smsl-audio.com/portal/product/detail/id/566.html
https://www.highfidelityreview.com/creative-sbs260-speakers....
Clear and distortion-free. Probably depending on how you drive your line-out, but mine just worked.
Stereo 2.0! (Giggle..)
The room isn't that large, but they really could fill it with sound, or the nearest neighborhood, if put on the balcony on summer evenings :-)
Find e.g. a tiny TPA3255- or TPA3116-based amp. These are class D amplifiers chips made by TI. Buy one of these from e.g. Amazon. Throw away/recycle away supplied chinese power supply. Buy a a used laptop PSU for cheap.
My fav for your use case: Fosi Audio TB10D.
You suggested an amp. The fact that I'm able to use a headphone jack to connect my speakers should tell you I don't need an amplifier. The question posed is how to connect those speakers if I no longer had access to a headphone jack. Currently the headphone jack is working fine.
For what it's worth, here's a comment that seems like it's get a perfect solution for me.
Sorry if I was unclear.
2. > Luckily, I have one of the last remaining TVs with a headphone jack.
I have no idea what you're on but maybe don't do it while HN:ing.
You can get a small ARC/eARC audio extractor with RCA or S/PDIF output and use your favorite amplifier or DAC with it.
Personally I use an eARC extractor to run S/PDIF to an audio interface (MOTU Ultralite Mk5) and an RPi running camilladsp handles room correction and active crossovers. Overkill at the moment for just a few studio monitors and a sub, but it'll be a great solution when I get around to building some custom speakers.
If you just want to get the eARC data, any S/PDIF input (USB or I2S-via-hat) would work just as well at 1/20 of the price :)
I want someone to fudge up a multiple shairplay setup (presumably by claiming multiple IP addresses, as AirPlay 2.0 apparently can’t handle multiple sinks at the same address) that can use a single multichannel interface like the Ultralite Mk5. This would make an excellent multizone audio setup at an entirely reasonable price.
If the only possible way of doing this is with a bulky receiver, I'd feel justified in complaining about modern AV stuff. Not because of the cost, but because of the size.
Anyway, thanks for your input.
On the other hand, HDMI switchers haven’t fared as well. I built a mini console rack with a switch and it doesn’t recognize several devices, even when manually selected.
In my limited experience, Yamaha handles HDMI-CEC significantly better than Denon/Marantz. As evidenced by the fact that I currently own a Marantz receiver and am reading this page, but back when I owned a Yamaha receiver, I had no need to care about all of this crud. Things somehow worked on the first try! I did not expect that. However, it conditioned me to expect that again with a different receiver (the sources and sinks are the problems, right? the receivers are super well tested because sitting in the middle and passing these commands around is their entire job, right? right?) which was a mistake.
(The actual issue with the Marantz is that it seems to be eating some kind of power-on command from the source, and not passing it on, so the TV never turns on if you try to turn on the receiver or the source. I have no idea how to fix this, short of following in the path of this article.)
I desperately need to work with CEC though lol, never had the time to actually test that.
[1] https://www.amazon.de/Yinker-hintergrundbeleuchteter-Unterst...
> without a bulky expensive receiver box
A "receiver" has been one of the standard options for making bookshelf speakers work for more than 50 years. A receiver is also not expensive. You can get a basic used one for under $100. I paid $30 for a perfectly working 5.1 Denon receiver with HDMI.
Your problem is that you aren't even using "Modern" AV stuff. If you were, your speakers and TV would both have HDMI Arc ports. Arc has been a thing since 2009.
> That's harder than it sounds though because you have to navigate the menu blind using short and long button presses with the one button.
Or you could unplug it and plug it back in.
I suspect that some of this is tradition because there are small solid state amplifiers. I'm surprised no one has made a small receiver for 2.1 system cause would be pretty common.
They do make half size receivers, but they typically only have half the power output.
If you only need 2.1 output and a quarter of the power, there are offerings that are basically the size of the minimum amount of ports: 2 pairs of speaker terminals, a pair of RCA terminals for subwoofer out, a HDMI port, a optical port, and power. But then it's not really a receiver and more just of an amplifier because they only have one HDMI input/output, having space for multiple HDMI ports basically increases the size to the offering above.
Sometimes I see cheap "amplifier only" designs that are about the size of a small 2U rackmount, but then you usually give up a lot of inputs and controls; they seem to be used either as PA amplifiers or as "extra room" units in the weird whole-house audio systems that apparently thousands of people had at one point and all dumped in the Goodwill.
If your speakers are active and don't need an amp, you can use a HDMI audio extractor, those are pretty small (mine is about half the size of my phone)
Others have mentioned toslink and I'd like to expand upon that.
When you get a new TV and no longer have a headphone jack to plug your powered speakers into, then you can just add a DAC that converts the toslink digital audio that your new TV outputs into the bog-standard line-level analog audio that your speakers understand.
DACs like this are available at all price points.
At the low end of the scale, some are less than $15 -- and they're tiny. If you can't hide it somehow then I might insist that you're not really trying.
And that's it. That's the entire missing link for where we are in 2025, wherein: A new TV will still have a toslink output, and your powered speakers still have an analog input.
(Tomorrow? Who knows, man. We aren't there yet.)
My old TV had real analogue out for speakers and it really did sound a lot better than what I've been getting through TOSLink and this cheapo DAC. Same Hi-Fi and speakers. I'm sure the problem could be solved with a more expensive DAC, but which one? How could I know?
I find this is one of those things where it's quite hard for the uninitiated to see through the cloud of 'audiophiles' saying that you must buy gold cables or your audio will sound like garbage, and still getting decent quality audio.
For instance: Apple-produced headphone adapters for iPhones are inexpensive -- like $10 or so. And inside of that diminutive adapter is buried a whole USB DAC, with a headphone amplifier. It's so seamless and low-cost that some folks think I'm crazy when I tell them this, but they measure great and also work great. (They work great as DAC/headphone amps for PCs, too. Android, not so much: It works, but there's a bug [that will probably never be fixed] relating to volume control and low output level.)
Anyway, I identify as an audiophile. I've spent several decades playing with this stuff, sometimes well beyond the level of "serious hobby" -- I've made some money doing this stuff. I've also spent some time in the studio, and in front of the stage making things sound good.
And I'm practical. I promise you that I can wire up a high-end stereo system with metal coathangers that will sound indistinguishable from something connected using only solid silver Kynar-insulated wire that is jacketed in cloth woven by Benedictine monks from the first cutting of wool from a single virgin albino Bolivian alpaca (for "purity") that has been dyed and imbued with post-civet Kopi Luwak (for "balance"), in any correctly-controlled blind A/B/X test.
Trust your senses. And by that, I mean: If it looks like bullshit, and it smells like bullshit, and it tastes like bullshit, then spit it the fuck out. :)
For sorting inexpensive products that actually work from those that have practical issues like hum or noise: That's what Amazon reviews are for.
But there are some very nice things for sale that aren't stupid-expensive boutique items. Schiit, for example, builds their own designs in the US and charges Buick prices for them instead of Bugatti prices -- and their website shows photos of what the devices look like on the inside, too.
...anyway, ground loops are usually real. Professionally, I've encountered them most-often in residential environments when converting a customer's television into any manner of home theater. 100% of the time I've discovered this, it was because some bonehead grounded the cable TV wire or the satellite dish to some ground that was separate and distinct from the home's electrical ground -- which should never, ever happen.
The loop would show up when we introduced the first bit of gear that had a 3-prong plug into their mix of things that previously only had 2-prong plugs. Adding the AV receiver, the subwoofer, or whatever tied the electrical ground to the stupid ground and current would flow between them, producing noise.
(And USB-C is ground-referenced, so keep that in mind. Toslink, though? That's fiber optic and thus also galvanically isolated.)
I had my LG C9 audio via the headphone jack going to amp and it worked fine. On one of the cheaper LGs I set it up similarly with optical cable and a tiny optical->rca converter.
The article here seemed to dive in, look at what was happening, and figure out some altogether decent & not absurd flows. It wasn't "easy", but it also wasn't totally absurd.
I get why you'd whinge & argue for a simple cable. But this was also a wonderful study, that showed steps, that I hope can bring joy & not just derision.
Turns out that there's a special pin on your APU that has to be wired up, and AMD didn't bother for the Z1 Extreme chips. I wish "wake on signal" was a universal option.
The common workaround if you had a kodi PC or something was to buy one of these things: https://www.pulse-eight.com/p/104/usb-hdmi-cec-adapter and run a HDMI cable through it. Because CEC is open drain like i2c is, connecting to it anywhere in your network of devices should work. (the HDMI spec mandated that the CEC pin needs to be connected, even if you aren't using it, from the first version) Just connect it to a spare HDMI port anywhere and you're off to the races.
Real shame these gaming-tailored devices don't support it natively. I wonder if the DP vs HDMI licensing battle is involved.
My Roku does this! It will turn on the TV but not the soundbar, which is so frustrating. Guess it’s somewhat normal.
Other devices like an nVidia Shield or the XBOX require that you press power/home a couple of times to take control of the receiver and switch inputs.
It took me a long time to diagnose why it seemingly wouldn't work with my Nintendo Switch 2.
I ended up disabling it on my PS5 because I never use the darn thing, but it kind of stinks since most TV's have 4 HDMI inputs.
But long press on Xbox logo button to e.g. accept a party invite -- switches to Apple TV. Not great.
The consoles are indeed awkward, but so are soundbars. And really, it seems like the TVs are the worst.
All can be solved with the boxes from HD Fury like VRRoom.
https://johnlian.net/posts/hdmi-cec/#fn:3
Where I talk about the craziness that happens when more than 3 playback devices are on in my system:
> ...if the one playback device (e.g. PS5) was on, changing input to another playback device (e.g. Xbox) was impossible, I'd get a quick black screen and the input snaps back to PS5. This is wild, but fortunately I only use one console at a time so it’s not a big deal.
I remember when I wad losing my mind diagnosing this, I ended up asking ChatGPT for help with deciphering the HDMI-CEC frames when this was happening. It told me about the 3 device limit being the culprit with the line "You’re not crazy, HDMI-CEC is."
Just looks like a Rube Goldberg/spoiled-brat-cash-pit server to me. This is really illustrative of the nonsense that media copyright has manufactured. I'm not going to solve "HDMI-CEC weirdness with a XYX" I'm going to download the movie from a torrent or run an emulator.
Worked pretty well, was nice to CEC-ify a pi program and eliminate the need for special-purpose hw/sw to interact with the audio player.
The CEC spec has all of the user control codes on the 2nd last page[1], in table 27.
[1] https://storage.googleapis.com/google-code-archive-downloads...
Why? Because Google Home's TV remote stuff can do a lot, but not turn on the TV. CEC can.
I have accepted that I am apparently in the minority with my setup. In fact I was actually surprised to read that OP has a Denon as, just by what I have read about the topic of home theater", everyone else seems to be doing just fine with a simple soundbar which has one! hdmi socket.
So, here is my setup: -Dumb TV (Panasonic. So old it doesn't have a CI+ module built in, it is "just" a CI module) -Denon AV Receiver -Nintendo Wii -Nintendo Switch Dock -Original Xbox -Blueray Player -HTPC -Satellite Receiver -AppleTV
Excessive? Maybe but I still own all that stuff, have room for it in my cabinet so I like to convenience of powering each of these on when I feel like it without having to unearth them from a storage room and then fiddle with cables to connect everything for just a short time of usage.
Basically everything is plugged into the Denon. And then a single HDMI cable goes from the Denon to the TV. So the TV stays on one HDMI channel and everything else happens on the Denon. Switch Inputs on there and you get the corresponding Audio/video signal from the chosen device.
So far I have been lucky that in order to switch everything on, I could use a Harmony One. I could simply program the power on command for the TV, then switch to HDMI1 and turn on the Satellite receiver. This was the default. Put it on a news station and you got yourself some background noise. If you want to switch, you just had to tell the Harmony to switch its input to any other device listed above.
It really irks me that the Harmony line is dead and I don't know what I will do should the remote, one day, stop to function. Now I wonder if I would have to go the Pi route to have that switch things around depending on devices announcing themself when turned on.
I also had a NUC that I installed a Pulse Eight CEC module into, but I never ended up using it, so it got passed on to someone else.
Yay!
* I can use the LG TV’s remote alone to control everything including the Chromecast and amp’s volume controls. * The amp automatically switches on and off with the TV. * Turning the Xbox on/off via its controller also turns on/off the TV and the amplifier together.
Mostly good, except sometimes when I have my Chromecast on and switch the Xbox on via the controller it gets stuck in an endless loop of flicking back and forth between HDMI 1 and HDMI 2, between Chromecast and Xbox. Nothing I can do will stop it except to power cycle the TV.
If anyone has experienced anything similar or has any tips on how to debug this that would be much appreciated!
I suspect it was probably a vendor — jabra — software issue when sending a signal to apple? But probably not worth fixing.
It has been worse than doing all the remote juggling switching mysel because it is non-deterministic. This article will help me debug it, but it’s a toss up which audio device the screen will pick, if game mode activates or not, and if some device waking in the wrong order will put another one right back to sleep. Even if I follow the same steps every time.
Jellyfin even has a TV mode that you can enable in a normal desktop browser. So my media PC runs the browser in kiosk mode, and it has CEC buttons mapped to keyboard presses. Guests have used it, and I don't think anyone could tell that it wasn't a "smart" TV.
https://github.com/gkoh/pico-cec
Sometimes when turning any of the set top boxes, the other one would turn on and its HDMI would become the active one. I couldn't simply turn off the box I didn't want to use because all the system would turn off.
The solution was to disable CEC on the TV. I still get CEC between the boxes and the receiver (for volume and HDMI active input) but I need to manually turn the tv on and off.
One really useful thing when getting started was to use `cec-ctl -M` to monitor the CEC traffic live. Like the author, I used the v4l-utils commands to interact with CEC but eventually got frustrated with them and rewrote my program in in Go!
I have found CEC to be flaky and hard to work with. I had to turn off CEC on my TV because it breaks everything, almost randomly switching inputs and turning on and off devices.
Now absolutely nothing of that works. The audio output on the TV is set seemingly semi-randomly depending on content!?. The volume controls just stopped working, and I can not FIND THE SETTINGS in the menus? I suspect it is required to completely redo the remote setup to see those settings, OR as I rather suspect: they broke this shit in purpose to get us to buy a new Google TV Streamer.
It works well, but CEC most definitely is the buggiest part of the setup. It's a reasonably elegant system, but it's just not implemented very well by most electronics. I ended up putting in a lot of retries: stuff like "send active source command; wait five seconds and send it again." Still, if you're willing to dive into the weeds, you can do some nifty stuff.
(I'd gotten a large LG monitor instead of a flatscreen tv, and it didn't talk HDMI-CEC but it had a serial-over-TRRS control interface, so I listened for messages on the bus and my media PC translated and relayed them to the monitor.)