sp193
Developer
By design, the game must be made to support the video mode. So to me, GSM is an option to enable the EDTV 480P mode for games that do not support it on their own.
The early SDK releases from Sony had no support for this mode, although the PS2 itself did. Even though this video mode was added around SDK release 2.5, it was up to the developer to implement it and older games are never updated.
Progressive scanning would allow for better texture clarity, since it's free of the limitations of interlaced scanning.
Some people with TVs that can only support one type of signal (e.g. NTSC or PAL) but not the other, will also use GSM to help change the video mode which the game was made for.
However, since the game is designed to have control over the whole PS2, introducing a new software component could upset the delicate balance which allows some games to work. Since nearly all games were released on read-only media, there were no updates...
Given how low-level the interface between the game and PlayStation 2 GS chip is, some games were also made to run on the characteristics of a interlaced video mode. Which makes switching over to a progressive video mode not straightforward; I added a setting to emulate the flipping of the CSR's FIELD field, but this doesn't solve all problems. For example, how does one re-combine 2 sets of scan lines into 1 image without an additional process? For such games, I think using the original video mode would be the best, so your mileage may vary.
There's no default. The default video mode is determined by the game itself - games are designed to use either PAL or NTSC.
All PlayStation 2 console models support the same set of basic video modes, but the earlier consoles may not be able to perfectly output the video signal requested by an imported game (the difference should be minor).
If you're going to do that, don't bother with GSM. Its purpose is to let you choose a different video mode.
I would suggest that you don't enable features that you do not use. OPL is a PS2 game loader. Games are designed to work with a specific set of resources. And by changing this balance, you're possibly going to jeopardize game compatibility.
To be blunt - if you're going to want the best possible compatibility for whatever reason, just buy your games and play with the original discs, on an unmodded console. It'll run exactly as how Sony and their licensed developers intended.
If you want to be even more extreme, don't get anything above the SCPH-70000 - since they documented that the newer models have caused incompatibility with certain titles. But I wouldn't suggest worrying about any of these, unless you want to play any of the affected titles.
You seem to be hoping for a generalized answer, but for a game console this old... it probably didn't work as how things do today.
PAL and NTSC are similar, but PAL has a greater vertical resolution. NTSC and PAL were analog video modes, developed and used by different territories over many decades of TV transmissions. NTSC has a height of 480 lines, while PAL has a height of 572 lines. The difference is minor.
PAL's refresh rate is 50Hz, while NTSC is 60Hz.
Other than how they'll never beat progressive video modes (assuming the game can be rendered using one) in clarity since they're interlaced, it also begs the question of the quality of the game.
If you played the PAL ports of some NTSC games, you may notice that the developers didn't always do good ports.
It's never a simple conversion: since the refresh rate is different, game that render frames based on the V-Sync periods will end up running at 5/6 their usual speed. The reverse is also possible for PAL titles that were converted to NTSC.
Since PAL has more lines - other than actually adjusting the game (e.g. art assets) to fit the height, some simply did letterboxing.
The resolution of the frame buffer, which gets rendered onto the screen, is determined by the game itself. They are typically smaller than or equal to the display size.
Games may use a smaller frame buffer (with letterboxing), due to how they use GS VRAM - which you can consider as technical limitations of some PS2 titles. So even if you changed the video mode to one which has more pixels, it doesn't really matter if the game still uses the same frame buffer resolution. For this reason, sometimes it's impossible to run away from all forms of letterboxing.
If you have a TV that can support both PAL and NTSC, you could pick up the better edition. Maybe also by reading reviews.
Here, Hertz (Hz) is the frequency of full frames drawn by the TV set. Also known as the refresh rate.
The Frames per Second (FPS) of a game is the rate at which frames are drawn per second. The refresh rate isn't strictly coupled to game FPS, as it's possible to draw more/less frames/s than the TV will refresh.