New nvidia chip and xvid...

[ciper]

This question is for Doom9!

How can the new chip accelerate Xvid encoding, unless the new codec was made specificaly to use some of that chip functions to encode (and i guess that xvid developers don't have access to the new nvidia SDK)? When they say it will accelerate mpeg 4 encoding, maybe that's refering to a very specific mpeg 4 codec (commercial) made by a well know company (maybe nvidia will launch it's own mpeg 4 codec, or make a deal with another well known company, like DXN or Nero).

[Doom9]

I suppose English is not your native language so you might have missed that my sentence was conditional. I said "IF!!! the chip supports". Right now there are no indications of any codec that would be accelerated by NV4x cards. Let's just wait till the chipset is officially launched, I'm sure we'll know more details after the launch.

[ciper]

I suppose English is not your native language
Yes, ;), it's not my native language, and yes i noticed it was a conditional sentence. Though, mine was also pure rethorical one, just to start a discussion about this issue! I tend to believe that support for Xvid encoding will not happen very soon (or at all), unless the next DirectX SDK has some support for that chip functions (a bulky example could be a DirectDCT Api(Discreet Cosine Transform) or DirectNeatAndFastGeneralMpeg4Algorithms, or DirectNAFGMA for shorts >:)). Either way, the Xvid team has to change a lot of things to adapt the codec to that thing, or i might be completely wrong, and in that case you can slap me at will ;)

cheers

[sysKin]

I personally have no idea how is it supposed to work. Sure, GPU can perform some types of calculations horribly fast - mostly the ones involving floating point and big arrays of data.

Mpeg-4 decoding or encoding does not use floating point at all, and the biggest chunk of continues data it works with is probably 128 bytes.

Hell it's not even possible to take advantage of SMP because any synchronization between CPUs is definitely too slow for anything mpeg-4 related. CPU-GPU synchronization, made over AGP, must be many times slower than that.

Let's wait and see. In the mean time, let me remind you that YUV overlays already help *a lot*, as ->rgb32 conversion would be (is) twice as slow as decoding itself.

:) Radek

[fl0]

here is the link to the news: http://www.theinquirer.net/?article=14524

here says that:

The PVR part is the most interesting as Nvidia claims that the NV4X generation will have support for no more and no less then MPEG 1/2/4 encode and decode as well as WMV9 decode acceleration.

so i know that XviD and DivX somewhat compatible with MPEG4 standarts, wouldn't be a chance to benefit from new Nv4X family GPU's ?

[vinouz]

@sysKin : could it be feasible to use the complete dx9 pixel shaders to render a comlete image. I've seen people making radiosity raytrace on NVidia boards, so that kind of hack wouldn't surprise me. Even if the card is not designed especially for it, if it can handle full decoding by itself in real time, that's far enough !
And for encoding, their high memory bandwith could be useful : when searching the best motion vector for a block, especially with new codecs such as h264 and its multiple frame reference MVs, it could take advantage of the enormous memory bandwith they have. Given their architecture, I'm not sure that full search would be slower than other algorithms. And having just to communicate a set of MVs/deltablocks back from the card every frame is not that big a bottleneck with agp I think.
I'm not in pixel shaders but skal may know far enough to try that ;). (well, that's my "state of mind")

[Soulhunter]

Originally posted by sysKin
I personally have no idea how is it supposed to work. Sure, GPU can perform some types of calculations horribly fast - mostly the ones involving floating point and big arrays of data.

Mpeg-4 decoding or encoding does not use floating point at all, and the biggest chunk of continues data it works with is probably 128 bytes.

Hell it's not even possible to take advantage of SMP because any synchronization between CPUs is definitely too slow for anything mpeg-4 related. CPU-GPU synchronization, made over AGP, must be many times slower than that.

Let's wait and see. In the mean time, let me remind you that YUV overlays already help *a lot*, as ->rgb32 conversion would be (is) twice as slow as decoding itself.

:) Radek
But the GPU could do all kinds of pp like de-blocking/ring, filtering (like de-noising) and maybe a better resizing (no more bilinear)...

Would be really nice !!!


Bye

[mf]

Originally posted by Soulhunter
maybe a better resizing (no more bilinear)...
Actually, I've mailed ATI Support already on that one... ;)

[Soulhunter]

Originally posted by mf
Actually, I've mailed ATI Support already on that one... ;) Yeah, but its just a single mail... :rolleyes:

We could start a mass request for such stuff here !!!

Discussing what features are the most wanted n' write them down...

Then beg all ppl here to mail them to ATI & NVIDIA !!!


Bye

[mf]

Originally posted by Soulhunter
Yeah, but its just a single mail... :rolleyes:
If one mail won't do it then no amount of mails will do it - the advantages are so obvious and clear, and I've given enough technical details - I had an allowance of 1024 chars in the input field and I used 1017. These are technical guys that hopefully love a challenge :).

[Joe Fenton]

I don't know about ATi, but nVidia folks can get complete docs and devtools for doing code on the video card.

http://developer.nvidia.com/object/cg_toolkit.html

I've got all the stuff from there. I'm currently reading the docs. My intention is to offload the color conversions and postproc from xvid to the video card and see how it works.

Anyone else who wants to give it a try, just get the toolkit.

[dragongodz]

i just responded to this same question in the genral forum
http://forum.doom9.org/showthread.php?s=&threadid=72137

maybe discussion about this should be moved there as this is not xvid specific and there is no need for 2 threads on the 1 subject.

[Koepi]

Thread closed, further discussion here please:

http://forum.doom9.org/showthread.php?s=&threadid=72137

Regards
Koepi