Wii Video Modes vs Rendering Resolution

[Downcry]

I’m trying to learn about how Wii video modes work.
My goal is to modify the N64 Virtual Console so that it renders in 240p.

Im also interested in the alternative of leaving the VC renderer intact but setting the Wii system resolution to 240p.

I’m not confident in my use of terminology, but my understanding is that Wii software writes to a framebuffer(?) which is distinct from the Wii’s video output. For instance, even when the system is set to 480i, games render internally at 480p before being output at 480i.

If that’s the case, then if I was somehow able to set the system resolution to 240p, a game would render at 480p and be scaled down to 240p when output.

This is less preferable to rendering at 240p, but it might be a simpler task.

I’m looking for any information that may help or point me in the right direction.

[JosJuice]

(11-11-2020, 02:27 PM)Downcry Wrote: I’m not confident in my use of terminology, but my understanding is that Wii software writes to a framebuffer(?) which is distinct from the Wii’s video output.

Yes.

(11-11-2020, 02:27 PM)Downcry Wrote: For instance, even when the system is set to 480i, games render internally at 480p before being output at 480i.

This is the case for most games. It is however possible for a game to e.g. render at 240p and then upscale when outputting. There is also a very small number of games that actually render interlaced.

(11-11-2020, 02:27 PM)Downcry Wrote: If that’s the case, then if I was somehow able to set the system resolution to 240p, a game would render at 480p and be scaled down to 240p when output.

There is no system setting for 240p, so I'm assuming you are referring to the 240p video output mode. The 240p output mode is more or less the same as the 480i output mode but with slightly different scanline timings – things like the horizontal resolution are unchanged between the two. Because Dolphin doesn't attempt to accurately emulate a CRT, this difference in scanline timing is ignored by Dolphin and 480i output is essentially equivalent to 240p output in Dolphin.

[Downcry]

JosJuice, Thank you for your response.

Where is the “video output mode” defined?
Is it defined in the apploader? or the main game executable? somewhere else?

I want to patch this, but I don’t know where to look.

[JosJuice]

I believe it is set by the game's executable at some point. Exactly where and how it's set depends on the game.

[Nintendo Maniac 64]

(11-11-2020, 08:36 PM)JosJuice Wrote: There is no system setting for 240p, so I'm assuming you are referring to the 240p video output mode. The 240p output mode is more or less the same as the 480i output mode but with slightly different scanline timings – things like the horizontal resolution are unchanged between the two. Because Dolphin doesn't attempt to accurately emulate a CRT, this difference in scanline timing is ignored by Dolphin and 480i output is essentially equivalent to 240p output in Dolphin.

Apologies for hi-jacking this thread, but may I ask why it is then that 240p and 480i output in Dolphin isn't actually 100% the same and a teeny bit blurrier on 240p than 480i? (see attached screenshots; these were taking with Dolphin running at completely stock settings)

[Downcry]

(11-11-2020, 08:36 PM)JosJuice Wrote: Yes.


This is the case for most games. It is however possible for a game to e.g. render at 240p and then upscale when outputting. There is also a very small number of games that actually render interlaced.


There is no system setting for 240p, so I'm assuming you are referring to the 240p video output mode. The 240p output mode is more or less the same as the 480i output mode but with slightly different scanline timings – things like the horizontal resolution are unchanged between the two. Because Dolphin doesn't attempt to accurately emulate a CRT, this difference in scanline timing is ignored by Dolphin and 480i output is essentially equivalent to 240p output in Dolphin.

(11-18-2020, 08:23 AM)Nintendo Maniac 64 Wrote: Apologies for hi-jacking this thread, but may I ask why it is then that 240p and 480i output in Dolphin isn't actually 100% the same and a teeny bit blurrier on 240p than 480i? (see attached screenshots; these were taking with Dolphin running at completely stock settings)

Thank you for posting this.
I actually was unable to get dolphin to run at anything less than 480p.
I even tried playing a Wii game that is allegedly 480i only and it was definitely running in progressive mode somehow.
The game was Star Trek Conquest.

[JosJuice]

Yes, Dolphin contains a little hack to always output as progressive even when the game says otherwise.

[Downcry]

(11-21-2020, 11:51 PM)JosJuice Wrote: Yes, Dolphin contains a little hack to always output as progressive even when the game says otherwise.

Is it possible to disable this “hack”?
I need to debug 240p/480i.

[JosJuice]

No, Dolphin currently doesn't have a code path for actually outputting interlaced video.

[AdmiralCurtiss]

I mean, you *can* technically, but it'll just cause the interlaced video frames to be output as if it was progressive, causing some extreme image jittering. If you're debugging that might be okay but don't actually expect to play a game that way. Check VideoInterface.cpp line 787.