Worklog Analyzing the Wii's Video Encoder

[Shank]

ALL INFORMATION UNCONFIRMED. ATTEMPT AT YOUR OWN RISK

Its believed to be unlikely that the gamecube video encoders could work on the wii.

But you know, I don't really like accepting no as an answer, so I'v been looking into it with my oscilloscope.

Its nothing guaranteed, and very early stages, but I believe its possible the two use the same encoding. These results are not verified as official bitbuilt information, but simply personal tests I have run using my oscilloscope.

Here is my first test:

Wiiflow Main menu
Composite 480i
No sound

Via 1: 20.9 microsecond period 0v-1.81v perfect square wave (50kHz)

Via 2: 0v No activity unless sound is made.

Via 3: 82 nanosecond period 0v to 1.75v (12.19 mHz)

Via 4: 324 nanosecond period 0v to 1.84v (3.08641 mHz)

Via 5: 0v no activity

Via 6: Digital Data, 74ns multiples peak to peak. 0v to 1.8v (13.5mhz)

Via 7: 0v no activity

Via 8: Digital Data, 74ns multiples peak to peak. 0v to 1.8v (13.5mhz)

Via 9: 18.2 Nanosecond period, perfect sine wave of .6v to 1.2v (54mHz)

Via 10: 148 nanoseconds period, 0v to 1.83v (6.75mHz)

Via 11: Digital Data, 74ns multiples peak to peak. 0v to 1.8v (13.5mhz)

Via 12: Digital Data, 74ns multiples peak to peak. 0v to 1.8v (13.5mhz)

Via 13: Digital Data, 74ns multiples peak to peak. 0v to 1.8v (13.5mhz)

Via 14: Digital Data, 74ns multiples peak to peak. 0v to 1.8v (13.5mhz)

Via 15: Digital Data, 74ns multiples peak to peak. 0v to 1.8v (13.5mhz)

Via 16: Digital Data, 74ns multiples peak to peak. 0v to 1.8v (13.5mhz)

Based off of this test:
Just like the gamecube ave, this has 8 digital video lines and a 54mhz clock. Im not saying its a fish, but it certainly smells fishy

 

[Noah]

Nice! I'd love to see where this can go in terms of using things like the GCVideo with the Wii.

Could totally be possible. If you asked me a year ago if we'd have Wiis the size of credit cards, I'd say hell no. Can't wait to see how this comes along!

 

[Aurelio]

Unseen/ikorb already confirmed it (iirc it's mentionend on GCVideo github page), but the Wii AVE uses 1.8v logic, while the GC works with 3.3v logic.

 

[Shank]

Well I'm happy that my theory is correct, but I'm also disappointed because I thought I was onto something new haha. Every time I brought it up I was told it operates completely differently, and I should stop asking.

That's interesting. Would you be willing to link me to the sauce of this info? I'd love to look into it more and see how it can be applied.

I see a bright future with digital and other options on the wii.

 

[Aurelio]

https://github.com/ikorb/gcvideo/tree/master/Hardware/gcvideo_lite_09
At the end of the page:

Measurements on a Wii board indicate that thare is an internal video data bus that may use the same signals as the GameCube's digital video port, but since the Wii already supports Component video natively there isn't much reason to actually use this board on a Wii. It may need some hardware changes as the Wii uses 1.8V signal levels instead of the 3.3V seen on a GameCube.

 

[Shank]

I just found it and came back to post a quote, but yea, id love to make a GC video Wii. I'll need to talk to mega about this one.

 

[Aurelio]

I just found it and came back to post a quote, but yea, id love to make a GC video Wii. I'll need to talk to mega about this one.

Why would you want to do that?

 

[JacksonS]

Why would you want to do that?

He's probably referring to getting DVI and HDMI from the Wii.

I wired up a GameCube AVE using this information and got a black and white garbled image:

This doesn't really mean anything because I was kind of using an educated guess as to where each data pin should go, but it's cool. I had to wire the 54 MHz signal from the Wii to the 27 MHz pin on the AVE, so obviously there is some incompatibility.

I also tried to wire up a component cable MX chip. I thought it would work because it does use 54 MHz, but I got no output.

 

[Aurelio]

He's probably referring to getting DVI and HDMI from the Wii.

I wired up a GameCube AVE using this information and got a black and white garbled image:

This doesn't really mean anything because I was kind of using an educated guess as to where each data pin should go, but it's cool. I had to wire the 54 MHz signal from the Wii to the 27 MHz pin on the AVE, so obviously there is some incompatibility.

I also tried to wire up a component cable MX chip. I thought it would work because it does use 54 MHz, but I got no output.

The problem is that the Wii GPU outputs 1.8V logic signals. You'd need a logic shifter for each IO pin able to work up to 54MHz

 

[cheese]

A few seconds of googling led me to this, a $0.50 chip that runs up to 380MHz when going from 1.8v to 3.3v
http://www.ti.com/product/sn74avc4t245-q1
And it has 4 io lines too

 

[Aurelio]

A few seconds of googling led me to this, a $0.50 chip that runs up to 380MHz when going from 1.8v to 3.3v
http://www.ti.com/product/sn74avc4t245-q1
And it has 4 io lines too

Sure, I didn't mean that it was hard to do, but you'd need to shift 11 lines. Is it really worth it?

 

[cheese]

Well if you change the GC video to support 1.8v (I assume the end goal) then no level shifting is required

 

[Aurelio]

Well if you change the GC video to support 1.8v (I assume the end goal) then no level shifting is required

That's true, but still I can't see any advantages in doing that since the Wii can already output 480p

 

[cheese]

Shanks reason is for HDMI. Honestly I'm only gonna end up using composite or rgb from the original av encoder, but whatevs

 

[Aurelio]

Shanks reason is for HDMI. Honestly I'm only gonna end up using composite or rgb from the original av encoder, but whatevs

In that case the XCS200A (the FPGA used by gcvideo dvi) should already be able to handle 1.8V without any issue

 

[watsug]

The gamecube apparently has better component video out than the wii, a gcvideo should solve this right?

 

[Aurelio]

The gamecube apparently has better component video out than the wii, a gcvideo should solve this right?

What do you mean exactly?

 

[Ampz]

I can't remember where in the forum but SS but up a video in a topic he made
these guys explained and compared how Component video on the Gamecube is better than the
Wii all thanks to Unseen.

 

[watsug]

People say that the wii component video out is inferior to the gamecubes, haven't seen it myself as I don't have gc component cable. Here's a comparison pic + info. http://retrorgb.com/gamecubevswii.html

Since the component video is encoded in the AVE-RVL bypassing it and using a gcvideo could give better video quality.

 

[Ampz]

Found it