HD Video Decoding on GPUs with VLC 1.1.0
by Ganesh T S on June 25, 2010 4:35 AM EST- Posted in
- Home Theater
- HTPC
VLC has taken the important first step towards enabling GPU acceleration for various codecs commonly used in high definition videos. However, they have been crippled by their application structure, resulting in the fact that they are unable to provide the same amount of acceleration as other methods like DXVA using MPC-HC / Windows Media Player. While the untested Arrandale provided around 5% CPU usage improvement for VC-1 decode, PureVideo VP2 had speed-ups of around 60% for H264 and 20% for VC1. PureVideo VP4 turned out to be the best of the lot when GPU acceleration is enabled. CPU usage was lesser by a factor more than 65% for H264 and 36% for VC1.
Are these numbers good enough for the occasional HD video watcher? I would say, yes, as soon as the GPU vendors fix their drivers for the remaining minor issues. But, for the HD enthusiast with terabytes of Blu-Ray backups, I would still advise sticking with MPC-HC / Windows Media Player / favourite software Blu-Ray player.
GPU vendors should get their act together and work with the VLC developers to ensure smooth interaction between their drivers and VLC. This has already been done between the MPC-HC / mplayer - VDPAU developers and Nvidia / Intel. VLC, being much more popular, should not have much trouble in this respect (as indicated by how long it took CatalystMaker to tweet regarding Catalyst support for VLC). The vendors and developers should also look into ways to further the performance gains that have been realized with this first release. It will probably not be long before all GPU vendors support this type of acceleration at the basic level. That would be time for the VLC developers to enable GPU acceleration by default, and take away the experimental tag associated with it.
On other HD media aspects related to VLC, it is heartening to note support for WMAPro audio in the past few releases. Would it be wishful thinking to see audio passthrough / HD audio bitstreaming implemented internally in VLC? Hopefully not! Anandtech takes this opportunity to thank the VLC developers for creating and supporting one of the best open source softwares of all time.
Note: Don't forget to check out the update section on the next page, where I have tried to address some comments from readers (both here, and also in private communication)
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puffpio - Friday, June 25, 2010 - link
uh that's not truethere exists some dvds that are encoded interlaced..some dvds that are of old tv shows, for example
ganeshts - Friday, June 25, 2010 - link
barniebg, I agree with you!However, VLC developers are more interested in maintaining consistency across platforms and the framework, rather than improving performance and quality on a single type of system.
Currently, VLC uses CPU SSE2 instructions to implement the Yadif deinterlace filter [ http://avisynth.org.ru/yadif/yadif.html ]. I am trying to find out how it compares with GPU deinterlacing (any benchmarks?). If the performance is similar, but we just take a CPU usage hit, it might not be such a bad thing after all (since VLC wishes to cater to the lowest common denominator amongst media player users)
ganeshts - Friday, June 25, 2010 - link
Note: VLC devs recommend use of Yadif over other deinterlacing mode options which might be availablepaulpod - Friday, June 25, 2010 - link
It is a bad joke for anyone to claim hardware acceleration of video when deinterlacing is not included. But you get what you pay for, I guess.Software and CPUs can decode any video format at full quality without much effort. It is deinterlacing that requires GPU acceleration because detection of moving diagonal edges is extremely compute intensive. And as people have pointed out, most TV broadcast is 1080i mpeg. Yes, the Olympics, the World Cup (in Spanish with better announcers than ESPN), and other little things like that.
Let's hope the simple API connections necessary for them to support deinterlacing will be in a future release, at least to the point where they pass control to the graphics driver.
Rainman200 - Friday, June 25, 2010 - link
Your opening comments about MPC-HC are a bit inaccurate.1) That guide linked to is overkill, intended for very specific anime people.
2) The CCCP pack installs MPC-HC but has nothing to do with it. Codecs packs are a bad thing in general go ask anyone on Doom9 forums though MPC-HC is directshow capable unlike VLC.
To enable DXVA playback under MPC-HC you just install the player and change the output to EVR-Custom thats it no other changes are necessary nor any codec packs.
If it doesn't work then it a hardware/driver issues but not the fault of MPC-HC.
That said its good to see VLC add this support, XBMC is also working on DXVA2/VAAPI and CrystalHD support.
ganeshts - Friday, June 25, 2010 - link
I first started using MPC-HC when I was on WinXP.I remember the countless nights I spent in trying to accelerate some HD files. It refused to do DXVA till some registry entries were modified to make it ignore L4.1 restrictions. Even then, some files would work better with the Cyberlink decoder, and hence I had to make mods in MPC-HC to load that filter. All in all, it was a bit of a trying (but ultimately satisfying -- after I moved to Win7) experience.
I agree that the recent releases work much better than the ones I used to tussle with, but I still see the comments list on that anime blog being updated years after it was first posted! I would assume that this means MPC-HC offers options / makes users want options which can easily make them shoot themselves in the foot!
PS : I love MPC-HC! All my MKVs and M2TS default to that, but for everything else, I still use VLC :)
ciukacz - Friday, June 25, 2010 - link
AFAIK there is no standardized API for HD audio bitstreaming under Windows (and probably under other OS's too). developers have to add it "per device". with a development team of 5 it is wishful thinking.Nehemoth - Friday, June 25, 2010 - link
Kmplayer had hardware acceleration since a lot of time ago and as VLC you don't need to install codecs pack, even better in Windows 7 you can use the system codecs if you want to.I would like to see kmplayer against VLC.
piroroadkill - Friday, June 25, 2010 - link
Kmplayer is a rip off of Media Player Classic...http://en.wikipedia.org/wiki/K-Multimedia_Player#C...
CSMR - Friday, June 25, 2010 - link
Spotty DXVA in VLC is not news. Even if VLC gets perfect playback, including subtitles, all popular formats, and is customizable, then you just have a competitor to MPC-HC, good but not exactly a step forward for the HTPC world.MPC-HC has no problems with DXVA playback on any modern mainstream GPU (including integrated). You do not need a tutorial to do this; the link is for people who want to get all the settings right, because MPC-HC is very customizable.
The only important free media players atm for HTPC users are MPC-HC, because it is the best, and WMP, because it is popular and integrated into WMC.