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PrettyBoyClone · Oct 30, 2004, 08:49 AM

I've looking around for infomation about Core Video, but haven't been able to find much. What i'd like to know, is what this can be used for besides applying filters.
I don't know much about OpenGL programming, but could this, in theory at least, be used for accelerating encoding of videosteams? Or where are the actual limits for what kind of tasks that would make sense to outsource to a GPU?
I'm assuming that a GPU in many ways compares to a DSP, but in fact I really don't know..

Millennium · Oct 30, 2004, 12:47 PM

Originally posted by PrettyBoyClone:
I've looking around for infomation about Core Video, but haven't been able to find much. What i'd like to know, is what this can be used for besides applying filters.

Not much, as I understand things. It's all about display and filtering, and possibly compositing at all. It's a rendering library, not a decoder or encoder.

I don't know much about OpenGL programming, but could this, in theory at least, be used for accelerating encoding of videosteams?

Probably not. Encoding is a very different task from rendering, which is what CoreVideo is meant for.

Or where are the actual limits for what kind of tasks that would make sense to outsource to a GPU?

For the most part, only rendering-related tasks. This isn't going to speed up encoding or even decoding, only display. This will make video playback much better, because to be honest graphics have been the real bottleneck ever since the 10.0 days. But encoding (and decoding, actually) won't see much if any performance boost. On the other hand, since it doesn't touch these areas, it won't hurt them either.

I'm assuming that a GPU in many ways compares to a DSP, but in fact I really don't know..

Not really, I'm afraid. GPUs are geared almost entirely toward rendering and nothing else. Even 3D-accelerated games have to compute the whole scene with no help from the accelerator; they then hand the scene off to the card to be drawn. This is why a fast card in a slow computer won't help the framerate; if the CPU is the bottleneck then a graphics card won't do all that much. The frames will be prettier, but you won't get much of a framerate boost. Having played Final Fantasy VIII in a VPC-emulated computer (running on a PowerMac G3) back when VPC supported Voodoo2 cards, I can personally attest to the effect.

This said, it is possible to use a GPU for other processing tasks. I seem to recall, for example, a Tetris clone that ran only on a particular NVidia card and didn't use the CPU for anything once it had loaded. However, this is generally not a good idea; aside from being extremely difficult to do, GPUs are so heavily-slanted towards video rendering that they tend to be quite slow at doing anything else.

PrettyBoyClone · Oct 30, 2004, 01:11 PM

Thanks for clearing things up, but isn't rendering in it self signal processing? Great reply, but still a bit on the speculative side eh?

I'm fully aware of the difference between being able to ship tasks over to the GPU and having it make sense performancewise.

Btw, i just saw the WWDC Graphics and Media State of the Union session. There's great stuff presented there. Have a look :

http://stream.qtv.apple.com/events/j...m_sotu_ref.mov

AirSluf · 01:15 AM

jamil5454 · Oct 30, 2004, 08:13 PM

If you want hardware-accelerated encoding and decoding, you'll have to purchase a separate card. The GPU doesn't efficiently do encoding and decoding, unless you get an NV40 (Geforce 6800) which has an on-chip video processing engine. Which brings up another question - will CoreVideo support the 6800's video processing engine?

bowwowman · Oct 30, 2004, 09:18 PM

. Which brings up another question - will CoreVideo support the 6800's video processing engine? [/B]

Perhaps the better questions for us to be asking are:

Was CoreVideo the reason nVidia agreed to build the 6800 for Macs?

or

Was the 6800 the reason Apple implemented CoreVideo to start with?

Kind like the old "chicken & egg" question, huh ?

PrettyBoyClone · Oct 31, 2004, 04:06 AM

Ok, i looked around a bit and it seems that many new cards have some level of mpeg encoding/decoding support built in. This could of cource be harnessed by CV (og QT), but the implementations would be more specific than calling OpenGL.

As an example, here's the info for my radeon mob 9600:
http://www.ati.com/products/mobility.../features.html

Accelerated Home & Business Multimedia

Hardware acceleration for MPEG encoding and decoding, for DVD playback, personal video recorder and time-shifting applications

I also found this:

http://www.cse.cuhk.edu.hk/~ttwong/d...pu/dwtgpu.html

The DWT-GPU C++ class is a free open souce software module which you can incorporate into your application and perform fast discrete wavelet transform on large data set using the parallel power of current generation GPUs.

I bit technical, but to me it looks like some parts of encoding/decoding could be shipped of to the shader.

...i have wierd feeling, that my curiosity will force me to code the damn thing myself...

MindFad · Oct 31, 2004, 02:51 PM

Originally posted by PrettyBoyClone:
Thanks for clearing things up, but isn't rendering in it self signal processing? Great reply, but still a bit on the speculative side eh?

I'm fully aware of the difference between being able to ship tasks over to the GPU and having it make sense performancewise.

Btw, i just saw the WWDC Graphics and Media State of the Union session. There's great stuff presented there. Have a look :

http://stream.qtv.apple.com/events/j...m_sotu_ref.mov

Awesome, thanks for the movie link. I didn't even know they had those. Is no one else psyched as hell for resolution independence!?

That's great that Apple's moving forward with that. But I don't remember him saying if it would actually be in Tiger or not. Will it?

PrettyBoyClone · Oct 31, 2004, 03:09 PM

Here's another one from the QuickTime State of the Union:

http://stream.qtv.apple.com/events/j...t_sotu_ref.mov

Not quite as meaty, but still interesting.

The media one has some pretty wicked stuff in it. The Core Video demo, where the individual frames fly away from the back of the film (like from a deck of cards) really blew my mind.

Now it seems that Motion is just a frontend to what is burried in Tiger. When it's released we will see some crazy shite in apps on our beloved platform. Yay!

Resolution independence only means something to me, if i get to set it to a negative factor. I could really use some more real estate on this PB of mine

-But it won't be activated in Tiger, so here's to waiting!

It also seems Core Image really will speed up drawing a lot. Like 2x - 10x or something in real world Quarts stuff, which includes the whole damn gui.

It's greeeaaaaaat !

P.S. Still need some technical info on the relationship betweenn CV and QT, if anyone has some insights to share..

MindFad · Oct 31, 2004, 03:15 PM

Ah well. Still good to know that Apple's hard at work on it. The resolution independence will probably show up in 10.6.

PrettyBoyClone · 04:40 PM

Just booted into 8A268 to try out the resolution independence.

Pretty cool i must say

Right now I'm writing this in Safari at a 100% resolution, but the finder is running at 75%. I have a screendump, but don't really have a place online to dump it. Anyway, it's easy to imagine how it looks.

Besides that, things seem really, really snappy.

Edit: I'm running it on a PB15 with 1280x864 native resolution. My new virtual res is 1706x1138. Look relatively good, but it's quite buggy.

Horsepoo!!! · Oct 31, 2004, 04:52 PM

Originally posted by PrettyBoyClone:
Just booted into 8A268 to try out the resolution independence.

Pretty cool i must say

Right now I'm writing this in Safari at a 100% resolution, but the finder is running at 75%. I have a screendump, but don't really have a place online to dump it. Anyway, it's easy to imagine how it looks.

Besides that, things seem really, really snappy.

Edit: I'm running it on a PB15 with 1280x864 native resolution. My new virtual res is 1706x1138. Look relatively good, but it's quite buggy.

Use http://www.imageshack.us/ to post screenshots.

PrettyBoyClone · 06:16 AM

Here you go!

edit:image removed.

MindFad · Oct 31, 2004, 10:35 PM

Friggin' awesome.

How do you even turn on the res. independence?

zachs · Oct 31, 2004, 10:54 PM

Originally posted by PrettyBoyClone:
Just booted into 8A268 to try out the resolution independence.

Pretty cool i must say

Right now I'm writing this in Safari at a 100% resolution, but the finder is running at 75%. I have a screendump, but don't really have a place online to dump it. Anyway, it's easy to imagine how it looks.

Besides that, things seem really, really snappy.

Edit: I'm running it on a PB15 with 1280x864 native resolution. My new virtual res is 1706x1138. Look relatively good, but it's quite buggy.

Buggy it is. Everything is really choppy when I change the resolution in Quartz Debug. Does that happen to you too?

Catfish_Man · Oct 31, 2004, 11:08 PM

Originally posted by MindFad:
Friggin' awesome. How do you even turn on the res. independence?

Through the Quartz Debug program in the developer tools. There's no "real" way to turn it on yet, because it's experimental.

PrettyBoyClone · Nov 1, 2004, 02:29 AM

Originally posted by zachs:
Buggy it is. Everything is really choppy when I change the resolution in Quartz Debug. Does that happen to you too?

I didn't experience much choppyness, but I did see a lot of draw bugs.

Btw the developer note for RI clearly states, that this will not be turned on by default in Tiger, but will eventually be availible to the user in the Displays Prefs Panel as a scaling factor.

MPMoriarty · Nov 1, 2004, 02:42 AM

I don't understand some of the benefits that will come from this resolution independence interface. What does it exactly do for the end user?

Mike

Nebagakid · Nov 1, 2004, 03:19 AM

i hope it would be per-app-able set.

What about that Quicktime Core Video demo? Man, that was wild!

PrettyBoyClone · Nov 1, 2004, 04:02 AM

Originally posted by Nebagakid:
i hope it would be per-app-able set.

What about that Quicktime Core Video demo? Man, that was wild!

Whenever it is released, it will be a global setting.

The only reason that it can be done on seperate apps now, it because it only happens through Quartz Debug and relaunching of individual apps.

The benifits are many. First of all, it's a move away from the 72 dpi assumption, so you can use panels with 150dpi or something else and still retain a good measurement on the screen. Second, it enables you to have a virtual resolution different from your native resolution. In effect, you get to choose which resolution you want your display to run at, unlimited by the physical resolution af the display. Besides those, a good imagination can bring it even further, think small divices.

And yes, Core Video will make the tiger wild.