I still need to put some work in balancing the color of the lights but its good enough for now.
Its 266 WS2812B LED's hooked up to an arduino. The video signal is captured by the Pi using a frame grabber and sends the LED states to the arduino nano over usb serial. I used Hyperion and OpenElec for software. I'm thinking about doing a write up about it, because none of the guides I could find online were up to date, and there's issues with adalights arduino sketch supporting over 256 LED's that might stump some people.
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I got a HDMI splitter into a HDMI->AV then into a UT007 based framegrabber. I think the only downside is that I don't think its possible to push 4K footage down to the TV (with any consumer hardware). The splitter supports 4K but the HDMI -> AV converter does not. So i'm stuck with 1080P. I could probably find a workaround by pumping a duplicate display out of my PC, but its a bit of a hack.
The TV is a 65".
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With enough HDMI ports on your video card you could duplicate a display and pump 4K along with 1080P down to the framegrabber, but it won't work for a standalone 4K device. Ultimately I'm going to hook this up to my steam link, so at the moment 4K isn't a concern for me.
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The only latency in this system will be from the LEDs matching the color of the video signal. That seems to be somewhere under 200ms. otherwise my HDMI cable is still plugged directly to my TV, although it goes through a powered HDMI splitter which is not known to add any additional latency.
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Also, is there a way to turn off the lights without unplugging them.
Not really no, you could wire a button to the PI to stop the hyperion service, or modify the arduino sketch to have a button that does that.
My current plan is to stick a power bar on the back of the TV that will power everything here. currently the framegrabber displays a test pattern when i unplug the HDMI source, which makes the back of my TV a rainbow.
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LEDcStrip?:60 led/m
I think 144 would be way to much, at 60 they already blend nicely.
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Right now its not perfect, its not great at browns/yellows/whites (i've been watching westworld) and the LEDs are a bit bright, especially when there's a dark room with a bright window on the side of the frame. But with hyperion i can adjust the colors/intensity until I get it to some ideal settings, it shouldn't be too hard. I'll probably get around to it today.
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Can you do this w/o andruno?:
Yes, but you need a specific type of LED strip.
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flickering?: Its heavily dependent on your power supply, I got a 10A dedicated to the leds, and i had to drop the intensity because it can't handle all of them full white.
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Does this degrade the quality of your TV?:
Kind of, but not how you think.
I got a 4K HDMI splitter that splits the input from my PC. One signal goes to the TV and the other goes to the AV converter and down to the framegrabber. Since the AV converter can only accept 1080P so thats the maximum my PC can put into the HDMI splitter. If I find a 4K AV converter it will support 4K footage also, otherwise its stuck at a max of 1080P due to that converter.
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Where does the power for the WS2812B strip come from? Is it just the Arduino? How much current does it need?:
I have a 5V 10A power supply i'm using. but I really need about 15A to drive them fully...
they recommend 60mA per LED at full white, so I need about 80 watts :S
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Another dude: I built one of these as well! It's a shame more people don't know about them. Mine works from any HDMI source. It uses a Raspberry Pi 3, HDMI splitter, HDMI to RCA converter, then a RCA to USB. demo pic: http://i.imgur.com/1cO5zIC.jpg

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