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bluetigger68 · **Posted:** 27 Sep 2009, 17:07

Hey there,

i'm having slight difficulties using the corecodec on an acer aspire revo nettop with an atom cpu and a cuda powered nvidia ion (9400m) gpu.

I have several mpeg4 mkv some mkv are decoded by corecodec using cuda some aren't using cuda while decoding.

The same problem is occuring on my notebook using a 8600m gt.

On both systems the latest drivers are installed and cuda is definetly running as some mkv are making use of cuda.

I've analysed the files and can see no difference, any suggestions?

Thanks

bluetigger68

flynn · Joined: 24 Sep 2009, 17:26 **Posts:** 12 **antispam:** No

Just to be clear, are you saying all of these MKVs are decoded by CoreAVC? so you see the tray icon show up every time, but sometimes it's blue and sometimes it's green?

I wonder if you've found a bug similar to what's going on in VMC where it will only use CUDA if playback is started in windowed mode.

bluetigger68 · **Posted:** 28 Sep 2009, 13:50

flynn wrote:

Just to be clear, are you saying all of these MKVs are decoded by CoreAVC? so you see the tray icon show up every time, but sometimes it's blue and sometimes it's green?

I wonder if you've found a bug similar to what's going on in VMC where it will only use CUDA if playback is started in windowed mode.

Thats correct. All MKVs are decoded by CoreAVC but sometimes the tray is green and sometimes it stays blue depending on the mkv you're watching.

It doesn't make any difference when starting windowed or fullscreen and there is no different behaviour when using different apps for playback.

greets

bluetigger68 · **Posted:** 29 Sep 2009, 10:40

Nobody out there with a smart hint?

Tranquil · Joined: 02 Jun 2009, 12:37 **Posts:** 17 **antispam:** No

bluetigger68 wrote:

Nobody out there with a smart hint?

Maybe it does not meet the specs that must be fulfilled to decode by cuda?

bluetigger68 · **Posted:** 29 Sep 2009, 15:20

you´re talking of what specs? Specs of the files or of the machine on which the files are decoded?

flynn · Joined: 24 Sep 2009, 17:26 **Posts:** 12 **antispam:** No

I would guess he means specs of the file - but my understanding of the CUDA support is that if CoreAVC can decode it via software, it can decode it using CUDA (given the right hw, and VMC in window'ed mode : ). Period.

I can't repro the problem here. There must be something strange about the MKVs that turn the tray icon blue... can you find out more about the encoding of the video inside the those MKV containers?

bluetigger68 · **Posted:** 30 Sep 2009, 04:09

I've already done that as written in my initial posting. the files are all mpeg4 encoded.
To be exact they are all V_MPEG4/ISO/AVC which is the matroska codecID of H.264.

Given that there shouöld be no problem using cuda as coreavc isa codec designed for decoding H.264 files.

I can't really understand it.

bluetigger68 · **Posted:** 30 Sep 2009, 06:09

I've just read this "NVIDIA CUDA accelerated decoding for interlaced streams (MBAFF and PAFF)", it seems that this is a part of the specs that must be fulfilled by the video files.

Can anybody tell me exactly what this means and how i can check whether my files are meeting this.?

Greets

squid_80 · Joined: 05 Dec 2008, 13:37 **Posts:** 190

To be decoded using CUDA the H264 streams must use less than 16 reference frames, not use lossless mode, and your video card must have enough onboard RAM. Given that both the systems you're testing with use mobile gpus, it's probably a lack of video memory. Again this is influenced by the number of reference frames - I have a Revo myself and it doesn't seem to have any problems using CUDA to play streams from Blu-Ray discs.

bluetigger68 · **Posted:** 30 Sep 2009, 08:25

Thats it!

The reference frames of all files not decoded with cuda is equal to 16!

Is it possible to change the number of reference frames with no effort or do i have to recode the whole thing?

Thanks for your help squid_80

greets

squid_80 · Joined: 05 Dec 2008, 13:37 **Posts:** 190

The streams would have to be re-encoded. There's no practical benefit for using that many reference frames anyway.
Also, this limitation has been removed for the next release.

bluetigger68 · **Posted:** 02 Oct 2009, 17:16

Well then i'll wait till the next release.

Thx for your help.

greets blue