Advanced deinterlace filter ?

[rama]

Yep, there's a documented trick that masks aliasing by manually shifting the output one pixel each frame.
This would likely cause flickering in games with the progressive scan hack on. We try to detect the method
though and correct it in GSdx.
A general progressive scan hack is something we should implement, I agree.
It'd be nice to have a better interlacer though, for all those games where a progressive scan hack won't work
or where it requires constant manual adjustments to the output.

[hellbringer616]

Yadif (yet another deinterlacing filter) seems to produce prefect results. From what I saw. But it's pretty GPU intensive

[Kein]

Intensive even for your GTX680?

[kerframil]

Yadif (yet another deinterlacing filter) seems to produce prefect results. From what I saw. But it's pretty GPU intensive

Integrating Yadif strikes me as excellent idea. I don't see why it would be GPU intensive because, as far as I know, it is implemented as a CPU filter and is well optimized (supporting up to SSSE3). VLC is a notable implementer.

I've been loosely following PCSX2 development for years but seldom used it because I didn't have a PC powerful enough to make it worthwhile. That recently changed so I gave it a whirl to see how it would stack up to the real thing. What immediately struck me is that the de-interlacing methods employed by PCSX2 are bad.

Normally, I run my PS2 through an XRGB-Mini upscaler. It has a Marvell QDEO Kyoto G2 chip and its 480i de-interlacing is really good. PCSX2 just doesn't stand up to it, despite the benefit of having a purely digital video path.

Also, I'm wondering why PCSX2 has to de-interlace at all. Being an emulator, can't it simply read render the contents of the framebuffer whole at any given point, instead of having to process fields after the fact? I recall Pete (the ePSXe plugin author) saying something similar about one of his plugins years ago. I can't remember which - it may well have been his soft GPU plugin, where the VRAM would be fully emulated.

[Blyss Sarania]

I believe it has to do with the way the image is stored in the framebuffer. From what I recall, the even and odd fields are sometimes store separately, in different places.

I could be wrong though.

[kerframil]

I believe it has to do with the way the image is stored in the framebuffer. From what I recall, the even and odd fields are sometimes store separately, in different places.

Interesting. I realised that I was probably being naive and that there might be some aspect of the console's internals that makes it impractical.

Still, a good motion-adaptive de-interlacer can come very close to the quality of progressive output. The only problem is the additional lag. Hardware scalers demonstrate that it can be done well while still keeping latency low enough for general gaming purposes - presumably, by limiting the temporal scope of the algorithm in their "game" modes.

Patching games to run at 480p would be great but, having employed many different methods to do this, I eventually gave up on it. I found that it works well for only a handful of games, while causing odd - sometimes catastrophic - side-effects in others. This was all on real hardware though.

[Blyss Sarania]

ps2force480p (google it) worked well on many games for me. It patches the ISO. I've used it both on real hardware and PCSX2. TBH, I don't have a problem with the deinterlacing in PCSX2 myself.

I also had decent luck forcing progressive with Graphics Synthesizer Mode Selector homebrew on real hardware.

[kerframil]

ps2force480p (google it) worked well on many games for me. It patches the ISO. I've used it both on real hardware and PCSX2. TBH, I don't have a problem with the deinterlacing in PCSX2 myself.

I also had decent luck forcing progressive with Graphics Synthesizer Mode Selector homebrew on real hardware.

Yes, I tried many methods (including ps2force480p and GSM). My game library is not as vast as that of a collector but it is sizable, nonetheless. I found 480p patching to be a time sink, with proper results being uncommon. The symptoms include: contortion of the image or certain video modes, offsetting of the image along either, or both, axes and locking up during video playback, making some games with forced FMV sequences unplayable. After I got the Mini, I stopped bothering with it for the most part because 480i became acceptably good. If you were able to compare and contrast my console rig to PCSX2, you might think as I do. The difference is stark.

The one game where I always make a point of using GSM is Gradius V because it looks a lot sharper in 480p and there are no side effects. Well, almost. I have to mash the buttons to skip the opening FMV otherwise it locks up.

EDIT: Forgot to say that I haven't tried patching and using PCSX2 yet.

[Blyss Sarania]

For ps2force480p, once I found an offset value that worked, it seemed to work on all games. It was no biggie for me to utilize it, since I was ripping my games and installing to HDD with winhiip anyway.

I also played several games on a PC monitor with a homemade VGA cable using GSM to set 640x480. This worked well for me too.

The only time I notice interlacing in PCSX2 is in FMVs.

[kerframil]

For ps2force480p, once I found an offset value that worked, it seemed to work on all games. It was no biggie for me to utilize it, since I was ripping my games and installing to HDD with winhiip anyway.

Would you care to divulge this value?

I also played several games on a PC monitor with a homemade VGA cable using GSM to set 640x480. This worked well for me too.

The only time I notice interlacing in PCSX2 is in FMVs.

I use a Bravia KDL-55W905A. It's combination of quality and size makes it very easy to discern such nuances. There is no question that motion-adaptive de-interlacers are superior.

One thing to bear in mind is that PCSX2 does not perform linear scaling at 1080p, which, to some extent, can mask the artifacting caused by a simplistic de-interlacing algorithm. Good video processors perform true line doubling, expanding to 960px along the Y-axis. This helps to preserve sharpness and fidelity. Granted, the importance of that is more apparent in certain games than others - especially 240p games - but it does generally matter for low-resolution graphics.

The bottom line is that I get true line doubling along with superior de-interlacing by using a dedicated video processor. The quality of the results cannot currently be obtained by way of emulation [1]. It is the reason that I got into the business of acquiring certain video processors for retro gaming. The only way I could achieve better right now is to use an original CECHA or CECHB model PS3 but it lags by a full 2 frames when running PS2 games.

If these issues were addressed, I know that PCSX2 would beat the combination of console and video processor in terms of visual fidelity. I'll just keep my fingers crossed that it happens some day.

[1] RetroArch is getting very close to being ideal, thanks to its flexible display options and decent shaders. No PS2 emulation core though.