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
After installing VLC 1.1.0, I was surprised to find that Blu-Ray sample clips continued to stutter during playback. I then realized that GPU acceleration was disabled by default. The option is hidden in the Preferences window accessible through the Tools menu.
Experimental GPU Acceleration Option in VLC 1.1.0 > Tools > Preferences
The three graphs below show the maximum CPU usage during the course of playback with and without GPU acceleration (X-axis) for each of the 8 files listed in the previous section (Y-axis). A completely unwatchable video has no entry corresponding to it. Most of the videos showing 100% utilization were watchable except for a few stutterrs and dropped frames.
A quick look at the graph for the Intel i5-430M below show that the VLC - GPU interaction for H.264 is a complete failure. Upon initializing any H.264 stream, the screen turned completely green. On the other hand, VC-1 decode acceleration is not broken like H.264. CPU usage is lesser with acceleration turned on, but not by much. On being contacted with these details, VLC developer Jean-Baptiste Kempf indicated that the issue was quite simple, and was quite confident that the code would work as soon as the developer team had access to an Intel box.
Moving on to Nvidia's PureVideo VP2 decoder in the Quadro FX2700M, we find that both the L4.1 H.264 streams were accelerated without issues. However, L5.1 videos having more than 4 reference frames were rendered unwatchable due to extensive artefacting despite the fact that CPU usage remained low. From the same graph, we also find that VC-1 videos aren't accelerated as well as H264. This is due to the fact that the VP2 decoder doesn't provide VLD acceleration for VC1, but only IDCT. VLC manages to make use of the IDCT acceleration a little bit, but, obviously, the results are not as good as what one could achieve with VLD.
The GeForce G210M has Nvidia's latest PureVideo VP4 decoder (which supports acceleration for even MPEG-4 / DivX, but we are not testing those here). We observe that both H264 and VC-1 get accelerated as expected, but the L5.1 streams still have an issue. Jean-Baptiste Kempf seems to think that the L5.1 problem could be a result of issues with Nvidia's drivers as well as VLC code. A fix is expected once a bug report with a sample file is filed.
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vfigueira - Monday, June 28, 2010 - link
1201NI have a 3g Usb Modem (ZTE MF622) and a bluetooth mice (Genius Navigator BT905).
I use the 1201N manly for internet and movies on the move.
If i only use internet, the battery lasts a little more than 3 hours.
If i only use it for movies (hd content) i last more than 2 hours but less than 3.
The user experience is not bad, but could be better.
I had for a little time a Acer 1810T with a SU2300 and the experience was better.
Windows Media Player with K-lite, played Hd content flawless and smooth, and battery life was way better than 1201N.
The atom 330 is always at full power.
Asus should be working in a bios version, which could downclock the processor and support AHCI. The only 2 faults worth mentioning.
All the players i used, are the latest version.
smartalco - Sunday, June 27, 2010 - link
I still always have VLC installed because I have yet to find any video it won't play in 4 years. I very rarely watch movies on my computer (never blu-ray), and have a decent quad core, so CPU usage isn't a problem. When I find a video that VLC can't handle, I might consider something else. In the meantime, on with the performance increase!MrSpadge - Sunday, June 27, 2010 - link
Personally I don't like VLCs interface much and prefer ZoomPlayer. But seeing them adress this important topic with its diverse problems is very good and will ensure that I also keep VLC installed for all the cases ZoomPlayer can't handle.And thanks to Anandtech for testing - this is certainly not a trivial task. As becomes obvious to me when I consider all the abreviations in this article which don't tell me anything, except "probably somehow video related".
archer75 - Sunday, June 27, 2010 - link
It has everything built in! And it's still the preferred player of choice for HTPC's.Shadowmaster625 - Monday, June 28, 2010 - link
I have many avi files from 2005-2009 that used to play just fine on VLC. Now they don't work. It is retarded. I complain how WMP doesnt play certain mp3's, but this is just as annoying.david007 - Monday, June 28, 2010 - link
Mpc hc supports most of the codecs except few odd ones (real and quicktime) out of the box without having to install the codec packs, so why use vlc for other formats than mkv?Nx6 - Monday, June 28, 2010 - link
Interesting article, but it would be much more useful if there was some comparison to other CPU-only and/or GPU-assisted decoders such as CoreAVC.PR3ACH3R - Tuesday, June 29, 2010 - link
Thanks for the review, & for mentioning just how badly ATI have neglected their Blue Screening, Lockup Causing, DPC Spiking horrible DXVA drivers.I would be eternally grateful, if/when the fixed ati drivers ever come your way, if you can also check for these problems, that have been ignored in Anandtech for way too long:
http://www.avsforum.com/avs-vb/showthread.php?p=18...
ganeshts - Thursday, July 1, 2010 - link
Thanks for the forum post link.I will try to take these issues up with ATI once I have a testbed with their new card set up.
PR3ACH3R - Saturday, July 3, 2010 - link
Thank you very much for your reply.God bless you for taking it on, this has been going on since the 5xxx launch & has been ignored here so far.
Please fill us all in on this when possible,
All The Best.