Cloning the GameCube component cable

[Unseen]

@Unseen I downloaded the GCvideo-master.zip for the programming files I need but I don't see the .svf in the firmware pack like last time when I built one of these boards and I used a xilinx programmer instead of the lattice programmer.

Oh, sorry - seems like I forgot to generate that file. It's now in the repository - please tell me if it doesn't work, I can't test it right now.

[andre104623]

@Unseen I downloaded the GCvideo-master.zip for the programming files I need but I don't see the .svf in the firmware pack like last time when I built one of these boards and I used a xilinx programmer instead of the lattice programmer.

Oh, sorry - seems like I forgot to generate that file. It's nowin the repository - please tell me if it doesn't work, I can't test it right now.

Ok no problem I won't be able to test for a few weeks. Thank you

[Brenex]

Joined the site to follow this thread. Eagerly waiting for the possibility to get a board from mega

[Xaranar]

I just finished making my own from the Pluto IIx board, and it's awesome.

[tehtechnoguy]

I just finished making my own from the Pluto IIx board, and it's awesome.

how is the pluto board? the weird resolution thing seems really off putting. If i were to get one and set it up with a cube and convert the signal to component, I don't think my PVM would like it.

[bobrocks95]

What's weird about the resolution again?

[Xaranar]

I just finished making my own from the Pluto IIx board, and it's awesome.

how is the pluto board? the weird resolution thing seems really off putting. If i were to get one and set it up with a cube and convert the signal to component, I don't think my PVM would like it.

It's not perfect by any means, but it works. The 100Ω pull down resistor rectifies most problems with it, but not all displays will like its input format. I don't know what the component output from it is like as I use straight up HDMI. One thing that does seem odd is some people say that you should avoid running this through a Framemeister as the picture can display off-centre, I found this isn't the case with me. In fact, if I plug it straight into my monitor and enable DVI enhanced mode, whilst it works, the picture seems to wobble uncontrollably. This is actually fixed by running it through my Framemeister and setting HDMI direct to on on whichever input I use. Works like a charm.

[Xaranar]

Also, one thing I have noticed that isn't unique to the HDMI output, it's present on standard component although not as obvious, is if a game doesn't use the standard 640x480p resolution, and many of them don't, they use something like 660x448p, you can see the GameCube's dithering effect very clearly without the blurriness of composite to hide it. It's not present in any games that output in 640x480, but with any games that use a non standard resolution you can see it. With component, it looks more like scan lines, but with HDMI, you can see individual dithered pixels. Very odd.

[megalomaniac]

ive never seen any wobble, what title did you see this on?
...and the artifacts you describe, are you sure its not a result of using the Framemeister also...

everything seems to look sharp and clear on my end in both analog and digital versions...

[Xaranar]

No specific title causes it to wobble, it jitters regardless with enhanced DVI switched on and connected to my monitor directly. With regards to the artifacts, I don't think I'm alone in experiencing them, if you look at those close up screenshots of the comparison between the Wii and GameCube component output, you can see them, and I've watched captured footage from a GameCube with component output and progressive scan, and they are present. Some games display them more obviously than others, and only in certain areas. For example, Sonic Heroes and Shadow the Hedgehog do not exhibit them as they output in 640x480. Mario Kart Double Dash does show them, but very faintly, you have to look very hard to see them. They are present in Wind Waker, but only really noticeable in darker areas, like Forsaken Fortress, they are very obvious. Prince of Persia the Sands of Time they are always visible, same in Time Splitters 2. Like I said, I don't think it's anything wrong with the cube or the Framemeister, it's just something that the cube does.

Edit: Here is a link to show you what I mean, it's direct capture footage of Wind Waker using an HD PVR with progressive scan on component cables, and you can clearly see lines across the screen. As it's not being displayed on a CRT, you can rule out scan lines: https://youtu.be/rZWIKsyej9Q?t=4m13s

[Unseen]

No specific title causes it to wobble, it jitters regardless with enhanced DVI switched on and connected to my monitor directly.

Does your monitor claim to be HDMI-compatible?

[Xaranar]

No specific title causes it to wobble, it jitters regardless with enhanced DVI switched on and connected to my monitor directly.

Does your monitor claim to be HDMI-compatible?

Yes, yes it does.

[Unseen]

Yes, yes it does.

In that case it should work in theory, but since it doesn't in practice I guess that there is some minor "bug" in the output of GCVideo that your monitor doesn't like. Unfortunately I have no idea how to figure out where the problem is (HDMI protocol analyzers are ridiculously expensive), so I'm sorry to say that I can't solve your problem.

[Xaranar]

Yes, yes it does.

In that case it should work in theory, but since it doesn't in practice I guess that there is some minor "bug" in the output of GCVideo that your monitor doesn't like. Unfortunately I have no idea how to figure out where the problem is (HDMI protocol analyzers are ridiculously expensive), so I'm sorry to say that I can't solve your problem.

That's quite alright, running it as a direct passthrough through my Framemeister fixes the problem, it also suits me fine as my Framemeister can operate as an HDMI splitter so I don't have to keep swapping cables out.

Any word on the scanline/dithering effect I described? Like I said, I'm fairly confident that it's something the GameCube just does, as if you look at the youtube link I posted of the direct capture footage from Wind Waker, you can see artifacts resembling scan lines running across the screen.

[Unseen]

Any word on the scanline/dithering effect I described? Like I said, I'm fairly confident that it's something the GameCube just does, as if you look at the youtube link I posted of the direct capture footage from Wind Waker, you can see artifacts resembling scan lines running across the screen.

I don't see anything in that video that I would describe as "scan lines". Could you take a screenshot and maybe annotate it with Paint or similar to make sure we're talking about the same effect?

[Xaranar]

If you zoom the picture to full size, you can see the striped effect I'm talking about. I put it as a URL so you can see the full size image.



You can see them here, too, albeit very faintly.

[tesla246]

I couldn't help you earlier, but I remember reading this somewhere in this thread, so maybe I can point you in the right direction . The lines are supposedly a side effect from the Gamecube's internal scaler and have nothing to do with the HDMI output, aside from making it more visible. Tuedj explained it earlier in this thread:

The vertical stripes are from the GC's horizontal scaler, they appear on a lot of games.

For the jumpy image problem with the linedoubling I believe what meneerbeer is suggesting is to add one extra blank line to the top of the bottom field image to properly align the original scanlines with their intended display position, rather than implement some sort of deinterlacing algorithm.

Is there any more info I can find out there on this? Is it used to upscale a lower res back buffer to the standard output resolution or for some other reason?

Basically yes, the unscaled YUV data is resampled before being fed to the D/A converter.
http://hitmen.c02.at/files/yagcd/yagcd/ ... tml#sec5.3
HSR controls the stepping size, where each "step" is one tick of the 13.5MHz clock used to drive the output signal. The FCT registers may hold the weights used for the resampling (they are NOT used for anti-aliasing), in any case the values used are hardcoded in the SDK and not configurable by games.

A similar artifact in gamecube/wii games is visible dithering when the internal framebuffer has the alpha buffer enabled or anti-aliasing is active, due to reduced color depth (6 bits per channel when alpha is used, 5-6-5 when SSAA is used). This is normally very visible in Super Mario Sunshine due to lots of flat colored surfaces being used.

I remember seeing it in other games as well and being particularly visible during smoke effects. The quotes are from page 25 of this thread, you may read up on it a few pages before that.

[Xaranar]

I couldn't help you earlier, but I remember reading this somewhere in this thread, so maybe I can point you in the right direction . The lines are supposedly a side effect from the Gamecube's internal scaler and have nothing to do with the HDMI output, aside from making it more visible. Tuedj explained it earlier in this thread:

The vertical stripes are from the GC's horizontal scaler, they appear on a lot of games.

For the jumpy image problem with the linedoubling I believe what meneerbeer is suggesting is to add one extra blank line to the top of the bottom field image to properly align the original scanlines with their intended display position, rather than implement some sort of deinterlacing algorithm.

Is there any more info I can find out there on this? Is it used to upscale a lower res back buffer to the standard output resolution or for some other reason?

Basically yes, the unscaled YUV data is resampled before being fed to the D/A converter.
http://hitmen.c02.at/files/yagcd/yagcd/ ... tml#sec5.3
HSR controls the stepping size, where each "step" is one tick of the 13.5MHz clock used to drive the output signal. The FCT registers may hold the weights used for the resampling (they are NOT used for anti-aliasing), in any case the values used are hardcoded in the SDK and not configurable by games.

A similar artifact in gamecube/wii games is visible dithering when the internal framebuffer has the alpha buffer enabled or anti-aliasing is active, due to reduced color depth (6 bits per channel when alpha is used, 5-6-5 when SSAA is used). This is normally very visible in Super Mario Sunshine due to lots of flat colored surfaces being used.

I remember seeing it in other games as well and being particularly visible during smoke effects. The quotes are from page 24 of this thread, you may read up on it a few pages before that.

This is acually pretty useful information, thanks, though the stripes are horizontal, not vertical, and in fact, they aren't stripes at all, but interweaved pixels as made visible by the HDMI output.

[Unseen]

If you zoom the picture to full size, you can see the striped effect I'm talking about. I put it as a URL so you can see the full size image.

Oh, interesting - the horizontal scan lines didn't show up for me when playing the video in Firefox, but it's visible in Chrome. It does look as if someone had turned on a scanline generator and since the effect disappears during motion I would guess that it is present in the file that was uploaded to Youtube.

I don't remember seeing something like this on my Cube, but I'm not sure if I have tested an NTSC version of Wind Waker in 480p mode. Unless you explicitly turn on scanlines in GCVideo it shouldn't produce an effect like this, so my initial assumption is that the lines are generated by the Gamecube.

(and the scaling artifacts at the edge of the cap have been explained by someone else already)

[Xaranar]

If you zoom the picture to full size, you can see the striped effect I'm talking about. I put it as a URL so you can see the full size image.

Oh, interesting - the horizontal scan lines didn't show up for me when playing the video in Firefox, but it's visible in Chrome. It does look as if someone had turned on a scanline generator and since the effect disappears during motion I would guess that it is present in the file that was uploaded to Youtube.

I don't remember seeing something like this on my Cube, but I'm not sure if I have tested an NTSC version of Wind Waker in 480p mode. Unless you explicitly turn on scanlines in GCVideo it shouldn't produce an effect like this, so my initial assumption is that the lines are generated by the Gamecube.

(and the scaling artifacts at the edge of the cap have been explained by someone else already)

That's what I thought, as those lines are present when using the component cable on my setup, too. If I use the direct HDMI output, then you can see that those lines are not lines at all, but rather are dots arranged in a grid pattern but display as lines, likely due to the scaling of the display. As the poster before me quoted, if you look at where the original quotes come from earlier in this thread, he has included a picture gallery and his does in fact display vertical lines, and I would wager that because these artifacts are individual dots rather than lines, that this is due to display scaling as well.

[tueidj]

The annoying thing about the dithering (which is performed by repeating an 8x8 bayer matrix over the internal framebuffer when converting to YUV) is that in theory it's not meant to be observable when viewing live frames, IF the game devs have followed the recommendation of adjusting the framebuffer's vertical offset for each frame (which in turn causes the bayer matrix to be applied with a different offset on each frame). Unfortunately not many devs followed these directions.

[megalomaniac]

If you zoom the picture to full size, you can see the striped effect I'm talking about. I put it as a URL so you can see the full size image.

Oh, interesting - the horizontal scan lines didn't show up for me when playing the video in Firefox, but it's visible in Chrome.

HA,
i dont see it in chrome
here is my best attempt to capture the exact same frame in the youtube link posted before

windwalker.JPG

(109.12 KiB) Not downloaded yet

i dont see scanlines on my end

[marcus9199]

Finally got around to building my own. Excited about installing in the rest of my cubes.

[andre104623]

Finally got around to building my own. Excited about installing in the rest of my cubes.

Very nice I just built one lite version last night and it was hard soldering this thing. After comparing both DVI and analog version I can firmly say that picture quality is much better with the DVI/HDMI. I'm still waiting for the Shuriken video V2 PCBs to come back from the fab. I'll see how it performs compared to the pluto 2x since I'm using the 200a FPGA instead of the 50a.

This new job I got on monday is taking all my free time away but at least I'm making more money.

[megalomaniac]

I prefer analog picture quality...but either way, the pic quality is great on both analog or digital


some TVs do better with analog signals than others
some TVs dont display digital signals as well as others
some people cant see as well....some people cant hear as well....
so everything is mostly matter of opinion / preference