Compressed Hard Disk Images

[chris2922]

I know this gets batted around quite a bit but I have a question about CHD files.

I understand that they are basically a compressed harddisk image but I would like to know if uncomprssing them would make them easier for MAME to run.  Take Killer Instinct for example - my CHD file is just under 100mb.  Is there a way to uncompress the file, and if so, woud it be beneficial or a waste of time?

My system emulates the game no problem, but the video is sometimes a bit dodgy.  It would make sense if that was becasue the video files were being uncompressed on the fly.  Anyone?

[SirPeale]

Not only would it be a waste of time, but it wouldn't run.  The CHD is compressed in a format that Mame expects to find.  If it found something different it wouldn't run at all.

[chris2922]

Considering the quality of the games in question I

[SirPeale]

The video quality doesn't have anything to do with the compression of the image.  It has *everything* to do with how powerful the computer the game is being run on.  I was able to run KI and KI2 on my Athlon 1GHz, but occasionally it would hiccup.  This was also a few versions ago, and they have improved the emulation since then.

[lucindrea]

i would guess their is a way to alter the mame source to read the raw chd uncompressed , but concidering the whole thing is based more on cpu speed then the tiny time it takes to uncompress the chd into memory , i doubt it would make any differance.

[chris2922]

Im still surprised a P4 2.0 GHz isn't cutting it.

[SirPeale]

Im still surprised a P4 2.0 GHz isn't cutting it.

I'm guessing you don't understand how emulation works.

[chris2922]

Easy tiger.  If by 'understand how emulation works' you mean have specific technical knowledge on the subject then youre correct - i dont.  I doubt more than a handful of people who post here do either.  We just benefit from the skills of people who do.

But then you went and stated a couple of posts ago that your Athlon 1GHz ran them both fine.  Emulation aside for a moment, how should i not be surprised a P4 2GHz isn't managing it when an Athlon 1GHz is?  Well?

[quadmasta]

Emulation aside for a moment, how should i not be surprised a P4 2GHz isn't managing it when an Athlon 1GHz is?  Well?

The architecture and overall designs of the competing company's chips are completely different as well as the way they handle/process information.  When compared at the same clock speed IE: 1GHz the AMD chip will always outperform the equivalent Intel chip if they're both given similar resources. 

There are many many determining factors to his statement though.  He never said what OS he was running, never stated system specs, etc.  There's too much left unknown to deal with rash generalizations.

[SirPeale]

Sorry, I thought you were talking about CHDs in general, not just KI.  Yes,  that setup *should* be okay.  Perhaps it's a configuration issue.  What is your framerate like?

[chris2922]

No problem,
Framerates are great during fights, just not good when the video clips run.  It stutters every now and again making the voices or music repeat itself.  Kind of loses the efect... I guess its maybe something to do with MAME being strict on keeping timing exact.  I dont want to go on about it too much though as im sure these questions have been answered loads of times.  Infact im liable to get set on fire, not just flamed.

My system is Dell - XP Home, P4 2GHz, 512Mb RAM, GeForce 440MX.  Im currently testing all the emus and games ive got before deciding what to put on a new system im buying to install in my JAMMA cab.

[SirPeale]

What resolution are you running this at?

[chris2922]

Thats a good point.  Im using Windows command line MAME and haven't changed the ini file settings for video options other than messing with autoframeskip to help some 3d game run a bit better.  Heres the ini file im using:

### Windows video options ###
autoframeskip           0
frameskip               0
waitvsync               0
triplebuffer            0
window                  0
ddraw                   1
direct3d                0
hwstretch               1
cleanstretch            auto
resolution              auto
refresh                 0
scanlines               0
switchres               1
switchbpp               1
maximize                1
keepaspect              1
matchrefresh            0
syncrefresh             0
throttle                1
full_screen_brightness   0.000000
frames_to_run           0
effect                  none
screen_aspect           4:3