Transcoding of VC-1 [Archive]

qubic

2nd April 2007, 12:20

Hi

It looks like my computer is not fast enough to play HD video (ripped HDDVD - vc-1). MPC showes a framerate on 21-22 frames/s. So does ffdshow in graphedit.
The specs are: AMD sempron 3400+, 2GB mem., NVIDIA Geforce 6200 TurboCache.

Is there a way to transcode it to a lower resolution? Or is it better to reencode it to another format, ie. MPEG-4 (-2/10)?

regards

qub

noclip

3rd April 2007, 15:25

Your computer should play 1080p VC-1 just fine. If you want to re-encode, do 2 passes in x264 after shrinking it to 720p with AviSynth.

qubic

3rd April 2007, 21:17

Thanks for the reply.

Yes, I think it depends on the combination of demuxer/decoders....

qub

zambelli

5th April 2007, 00:39

qubic

6th April 2007, 21:45

Transcoding to H.264 of all things won't really help you in the decoding department.

When you play the VC-1 from the HD-DVD, do you use the Microsoft WMV decoder or Ffdshow's VC-1 decoder? If you're using the WMV decoder, you ought to be able to take advantage of DXVA decoding, though you might need to upgrade to a better Nvidia card to do that. Check their PureVideo support page to see if the 6200 supports VC-1 (Advanced Profile) decoding.

I have tried WMVideo DMO, Sonic video decode and Elecards MPEG decoder. WMVideo DMO seems to be the best, but still not good enough.
Ffdshow does not show VC-1, somehow?!?!

Thanks for the good advices. I will check the card.

regards

qub

jeffy

7th April 2007, 20:08

Check their PureVideo support page to see if the 6200 supports VC-1 (Advanced Profile) decoding.
http://www.nvidia.com/page/purevideo_support.html

stegre

10th April 2007, 07:58

FWIW, MS says:
Complexity Comparison

It is not enough to deliver high-quality video. A video codec must also be efficient to decode, particularly when the codec is implemented in hardware. Lower complexity means less silicon, lower cost, and fewer problems with power consumption and heat.

Because they are more sophisticated, VC-1 and H.264 are both more complex to decode than MPEG-2. Yet VC-1 is more than twice as efficient to decode as H.264. A study by 3GPP, a collaboration group that is setting 3G mobile phone standards, found that VC-1 Main Profile requires 25% fewer cycles than H.264 Baseline. It should be noted that H.264 Main Profile requires even more cycles than Baseline, because it includes highly complex arithmetic coding, also known as CABAC.

In fact, software decoding of VC-1 at 1080p (1920 × 1080 progressive) resolution is possible on today's off-the-shelf computer hardware. In the hardware domain, companies can do more with a single DSP because VC-1 is easier to implement.[emphasis mine]

[link here] (http://www.microsoft.com/windows/windowsmedia/howto/articles/vc1techoverview.aspx#VC1ComparedtoOtherCodecs)

qubic

11th April 2007, 10:24

Hi

thanks all.

I checked the nvidia support list, and it seems that h.264 and vc-1 is (the only) supported in my graphics card.

But what does the purevideo do? It's an ad-on software. Does it activate the h.264/VC-1 support, or what?

regards

qubic

zambelli

12th April 2007, 05:56

PureVideo is just Nvidia's fancy name for DXVA. All you need to do is install their latest video driver and with WMP11 installed, you ought to get accelerated playback for all WMV9/VC-1 profiles.

qubic

29th April 2007, 11:08

PureVideo is just Nvidia's fancy name for DXVA. All you need to do is install their latest video driver and with WMP11 installed, you ought to get accelerated playback for all WMV9/VC-1 profiles.

ok. But if I have a 128mb 6200 TC (I'm not completely sure what I have), it only supports vc-1, not wmv9?!?!? (In HD content).

I thought it was the same. (more or less. I have read your faq).

regards

--qub

bond

29th April 2007, 12:39

Transcoding to H.264 of all things won't really help you in the decoding department.i would not be surprised if decoding h.264 is faster than decoding vc-1 depending on the decoder and settings used

foxyshadis

30th April 2007, 01:49

qubic, they're the same, and according to nvidia's site, as long as you have a proper decoder you should be able to get the acceleration. Yours doesn't support HD MPEG-2 for some reason though. The only wmv9 that isn't part of VC-1 is the old complex profile, which is no longer even playable iirc.

http://www.nvidia.com/page/purevideo_support.html

zambelli

30th April 2007, 09:45

The only wmv9 that isn't part of VC-1 is the old complex profile, which is no longer even playable iirc.
No, it's playable - it just doesn't have any DXVA support

diogen

30th April 2007, 19:22

i would not be surprised if decoding h.264 is faster than decoding vc-1...H.264 is getting support - DXVA assistance - in the latest NV video cards:
http://www.anandtech.com/video/showdoc.aspx?i=2977

If NV's claim that the 8500 (~$100) is as good as the 8600 in the video department, that would be very good news.

Diogen.