However, I would gladly be proven wrong ;)
However, I would gladly be proven wrong ;)
While indeed PS2's hardware isn't anything cool, the reason that you see over and over those stupid as you correctly said resolutions is because of some oddities in the provided SDK tools of PS2. If they didn't use one of those resolutions it wouldn't pass Sony's standarization program and the game wouldn't get mastered. The reason that they did that was because they didn't want other developing companies/teams to do the effort to compete or show-off with a resolution fight to prove that they are good developers and fool people for the visual results, something that they continue to do to date with PS3. In other words they didn't want any of them to know how to utilize the hardware at it's fullest resolution wise because they kept that for their OWN internal use/studios/games. So even if the studio was able to render a game at a higher resolution, Sony wouldn't allow it.
Proof? Check at SMS Media Player. It uses 1262x612 as resolution on 720p, which is a "non standarized" by them resolution on the SDK and SMS uses PS2's hardware at it's fullest with High Bitrate stuff, nothing that could get compared even with the most resource demanding games such as GOW2.
My point that what I describe is always worth experimenting, it's not anything that it promises to give game universal results in any aspect including quality and speed.
Example: The first-party God of War 2 uses an internal resolution of 512x448, but the developer (SCE Santa Monica) also implemented the famous 'hidden HD mode' which is simply using a full frame buffer (640x448). They didn't make that the default for performance reasons (lower framerate / too many framerate drops).
And there are other examples, like the Tomb Raider games developed by Crystal Dynamics. As most games they are 512x448 by default, but they also included a progressive scan mode. To avoid the 'black border problem', they increased the internal resolution when using progressive scan, but not to 640x448 which would have been the obvious choice, instead they chose 576x416. Why would they use this resolution? It's certainly not a 'Sony-standard' resolution... the only reason I can think of is that they made that compromise to avoid a big performance difference between using 480i (512x448 internally) and 480p (576x416 instead of 640x448 internally).
Gran Turismo 4 is one of the 'field rendering' 640x448 games and it still offers a progressive scan mode. How is that possible? If there was so much processing power left they would've never used field rendering in the first place. I read somewhere they switched to 16bit color frames for the 480p mode and who knows what else they sacrificed to keep the framerate...
Anyway, I totally agree with you: It's always worth experimenting!
Still though, I am aware of all of that but as I said, it's always worth experimenting.
You have to agree that there are games on PS2 that their developers didn't even try or did the slightest effort to push the hardware at it's slightest, some of them I guess because of the crossplatform porting reasons, a good example is Digimon World 4.
To the contrary, I'd really like to see how much the framerate can be improved by decreasing the internal resolution. Maybe games like Killzone that are nearly unplayable due to sluggish framerates can get a nice performance boost by sacrificing some image quality? Although somehow I doubt it, these games probably are simply unpolished as a whole...
GSM line-doubles some games. That is mostly because of game's rendering behaviour. You can see this behaviour easily at the browser screen of PS2, after you exit from GSM with 480p enabled.
If the game doesn't have this behaviour, you can use GSM as it will be better than the best deinterlacing method (because the picture will have twice the resolution). Plus TVs aren't famous for best deinterlacing. I have a high-end TV and i can easily say GSM makes some games look much better. Final Fantasy X, Need For Speed Most Wanted etc.
Personally, I like using GSM in 1080i with games that'll work (like the Guitar Hero and Rock Band games outside of GH1, and I'm seriously considering hacking GH1 and killing the intro video to see if that's the only issue with GSM), even if the game has its own 480p support. Reason being, my set's upscaling is crap even with all the filtering options turned off, and so in 1080i the image is much sharper even though it's interlaced. I'd use 720p for the best of both worlds if it wasn't half the height of the screen but full width :P
The only thing I don't like about the PS2 that's relevant to this, is the nasty dithering. Not really visible on an SDTV, and barely visible on my set in 480i, but sticks out like a sore thumb in 480p and up. I don't think there's anything we can do about that, though. If I'm wrong on this, I'd be very pleased to find out :D
dithering? Do you mean upscaling? PS2 doesn't dither when you choose high resolutions. Dithering for ps2 is lowering the video from 24 bit to 16 bit (Mostly because of trying to avoid memory issues). At ps2dev, i saw a post to increase the quality of dithering, though i don't think i can find it now, plus i don't know if it can be applied to GSM or not.