Gba Emulation

[Squidge]

Squidge, how's Spot! going? ;P

Off topic! Reported! Temporary ban, 24 hours ;P

 

[Vimacs]

couldn't it work quite well to have a good scaler on the 940? I don't think memory bandwidth is to critical with gba, but of course im not sure.

 

[Exophase]

couldn't it work quite well to have a good scaler on the 940? I don't think memory bandwidth is to critical with gba, but of course im not sure.

Maybe, but memory bandwidth is definitely critical with video processing (even at that resolution, and especially if you go higher). If you go from RGB to YUV you can do filtered scaling in hardware, supposedely, but that too costs a good chunk of cycles, unless things are kept in YUV the whole time - I don't know how feasible this is for direct color effects like blending.

 

[Vimacs]

Im not entirely sure, but i think you can do that in hardware by having one yuv and one rgb layer and setting them to blend, i check the file again tomorrow if i find some time.

 

[Exophase]

Im not entirely sure, but i think you can do that in hardware by having one yuv and one rgb layer and setting them to blend, i check the file again tomorrow if i find some time.

Do you mean converting RGB to YUV in hardware? Then scaling the YUV in hardware too?

If you could get hardware to do all that then I don't know why no one has...

 

[Vimacs]

that are exactly my thoughts,
rlyeh implements lots of hw function in his minilib (as does rob in sdk2x) that no one else seems to utilize yet, but the mmsp2 is in my opinion totaly underrated, there seem to be so many useful functions in the hardware that are not utilized yet, lots of wasted potential.
Hardware layers with transparency, possibility of changing the framebuffer address(real dubble buffering! cheap scrolling), a dedicated bus from the 920 to the 940, and more.
Im not sure if these are really utilizeable, but im sure some of them are.

 

[Exophase]

that are exactly my thoughts,
rlyeh implements lots of hw function in his minilib (as does rob in sdk2x) that no one else seems to utilize yet, but the mmsp2 is in my opinion totaly underrated, there seem to be so many useful functions in the hardware that are not utilized yet, lots of wasted potential.
Hardware layers with transparency, possibility of changing the framebuffer address(real dubble buffering! cheap scrolling), a dedicated bus from the 920 to the 940, and more.
Im not sure if these are really utilizeable, but im sure some of them are.

You should put together a demo for some of these things..

If you can do hardware blits with colorkey transparency without a lot of overhead that might be useful to me too.

 

[zodttd]

I tried getting hardware RGB -> YUV -> SCALED YUV all in hardware, but I stopped work on it. It seems possible from the documentation laid out for the GP2X. I was trying to get fine scaling working at the time.

 

[StarG]

I stated my opinion already in chat but i just wanted to reiterate it here: unless its not documented its a nonexistant feature for developers. Of course over time some stuff gets discovered through experimentation but its still very tedious work.

You really should get contact with the devloper of FreeDO who claimed to have signed a NDA with magiceyes and have complete documentation (sidequestion: this comes at a price if i remember right - so he pay'd for?).

I would be especially interested in the video playback coprocessor. I assume its layouted is to accelerate some basic mathematical transformations so it would be interesting to get information how to access it.

 

[Squidge]

There are a couple of people on this board who have full docs on the MMSP2 (not just the datasheet), but unfortunately this also means they've signed an NDA, so all they can give out is object code, which is not much use to other devvers as we don't know whats possible from that.

 

[Blah]

This all sounds too much like Sony

 

[Squidge]

Relax, I've looked at the additional documentation, and to be honest, there's not much there that will benefit us. I've not looked at, nor do I have access to, any video decoding hardware documentation however.

 

[quartercast]

End of topic? :blink:

 

[slaanesh]

There are a couple of people on this board who have full docs on the MMSP2 (not just the datasheet)

Why is it a secret? You'd think that they'd want developers to use the hardware to gain the most out of it.
If GP knew that this was the case, why did they choose this hardware in the first place?

It's a bit frustrating having open source handheld with closed documentation so that devs can't make max usage out of the hardware.

 

[Squidge]

I don't know why it's a secret. For some reason, Magiceyes don't want the docs available publically as they contain "Trade secrets and confidential information". According to them, if you want the docs, you buy the dev board.

To be honest though, they say that about the datasheet also - it's not downloadable from there site unless your a registered developer with them, and that costs thousands. All you have access to is a very limited datasheet that includes no register information.

So there you have it - all the useful stuff has already been leaked. It seems the video docs are extremely hard to get hold of even if your a developer, as they simply seem to say that if you want to support video, you license there binary module.

Its the same with most of the powerful chips these days - They'll tell you what the chip can do, but to find out how to do it, you have to give them lots of cash, and sometimes you don't get the information even then. Look at NVidia's and ATI's embedded graphics chips for example. You get a driver for several versions of embedded Windows and nothing else.

 

[cowai]

Why can't the devs with the documents "help" the open2X team getting a better video support?

 

[hercule18]

Hi,

Just wanna say:
Zottd (it's you i guess) for your great GPSP Emu, all Gba roms tested ran fullspeed with sound @ 200Mhz

So a great THX to you.

Bye

Herc. h34r:

 

[Squidge]

because that would break the NDA?

They can't give out any source code, or comment on anything they have agreed non-disclosure for, so I don't see how they can help. The only thing they could possibly do is create another 940 binary lump, and then modify mplayer to use those changes. That could be dangerous, considering the original Magiceyes binary lump is provided only under additional license.

 

[cowai]

That's what I meant
Not sharing any source code, just compiling binaries for the open2x team.

Thanks,

 

[PokeParadox]

Hi,

Just wanna say:
Zottd (it's you i guess) for your great GPSP Emu, all Gba roms tested ran fullspeed with sound @ 200Mhz

So a great THX to you.

Bye

Herc. h34r:

GPSP is Exophase's baby... Zod did some work with the original port to GP2X but currently Exophase maintains it.