Gamecube HDMI output... could this work?

Started by Fwirt, November 28, 2011, 10:40:40 AM

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Fwirt

I already know that the answer is probably, "it's impossible, the signal format is proprietary", but just hear me out. That digital output on the back of the Gamecube drives me crazy. I find it extremely odd that the only cables produced for it (The component and D-Terminal cables) both just converted the digital signal into an analog one. I would settle for that, except that the cables are upwards of $50 nowadays! (And I thought Dreamcast VGA boxes were expensive.) The idea that you could get digital video straight from the Gamecube to a modern TV is really cool, but searching the 'net for people who have tried mostly lead me to threads that ended in, "you shouldn't try because it's probably impossible".

Obviously you could use an FPGA/CPLD to convert the signal to whatever format you want, but I was wondering if there was a simpler solution. On a whim, I checked mouser for HDMI transmitter chips today. I found one that claims to convert YCbCr video to HDMI. That piqued my interest, so I skimmed the datasheet, and it says that it can take input formatted in an ITU BT.656-like format. As it turns out, BT.656 is remarkably similar to what the Gamecube outputs (according to the wiki page)... Alternating packets of luma and chroma information, and a 27MHz word clock.

My question is,  do you think it would be possible to get this thing (TDA9981B) to convert the Gamecube's digital output to HDMI? Obviously you'd also need an external MCU to setup the chip, but that could be easily accomplished with something like an ATTiny45. It also looks like there's a couple of slight incompatibilities between the Gamecube signal and the BT.656 standard (BT.656 data always starts with Cb whereas the Gamecube's output always starts with Y, and if the wiki is correct the Gamecube doesn't output standard SAV/EAV signals) but the TDA9981B boasts a "programmable input formatter", so do you think it would be possible to work around them? I'm not sure if I have the time or resources at the moment to try this, but I just wanted to throw this out there and see if you guys think I'm completely insane.

Actually, I just noticed that the guy in this thread was discussing the same chip... I think I'm in the same boat as him. Feel free to make fun of me for not wanting to spend $50+ on signal conversion options.