I'll try to sum up the above stuff into some pointers:
*The Playstation 2 was designed to be played on traditional TV systems and produces an interlaced output image.
*A PC screen has a progressive image, so to display PS2 output the images must be deinterlaced.
*PS2 games use different methods to produce the interlaced images. They might separate a full frame into 2 fields, which can be easily combined into a full frame with deinterlacing. Alternatively they might use different methods to draw interlaced fields combining half-images that are taken half a frame apart, which is designed to work well on a tv using an interlaced image.
*There are various methods to deinterlace video, each producing different problems or artifacts of their own. No deinterlacing method is perfect.
*Playing PCSX2 without an interlacing mode shows the game in it's original interlaced form. Using an interlacing mode applies a deinterlacing stage to the image output. The wikipedia link below on deinterlacing shows what they do.
In conclusion:
*PS2 games that use inherently progressive output (using fields of the same frame) can be displayed perfectly.
*PS2 games that use inherent interlaced graphics can only be displayed using various forms of deinterlacing. These always produce different types of approximations which might or might not look perfect, depending on the nature of the interlaced source image.
There are also extra details about this stuff to be read at:
Wikipedia: Interlacing and
Wikipedia: Deinterlacing
*The Playstation 2 was designed to be played on traditional TV systems and produces an interlaced output image.
*A PC screen has a progressive image, so to display PS2 output the images must be deinterlaced.
*PS2 games use different methods to produce the interlaced images. They might separate a full frame into 2 fields, which can be easily combined into a full frame with deinterlacing. Alternatively they might use different methods to draw interlaced fields combining half-images that are taken half a frame apart, which is designed to work well on a tv using an interlaced image.
*There are various methods to deinterlace video, each producing different problems or artifacts of their own. No deinterlacing method is perfect.
*Playing PCSX2 without an interlacing mode shows the game in it's original interlaced form. Using an interlacing mode applies a deinterlacing stage to the image output. The wikipedia link below on deinterlacing shows what they do.
In conclusion:
*PS2 games that use inherently progressive output (using fields of the same frame) can be displayed perfectly.
*PS2 games that use inherent interlaced graphics can only be displayed using various forms of deinterlacing. These always produce different types of approximations which might or might not look perfect, depending on the nature of the interlaced source image.
There are also extra details about this stuff to be read at:
Wikipedia: Interlacing and
Wikipedia: Deinterlacing