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
It is time for HTPC enthusiasts to rejoice! Videolan announced the availability of VLC 1.1.0 a couple of days back. VLC's popularity soared in the mid-2000s when standard definition videos were all the craze, and CPUs were powerful enough to easily decode them. Over the last few years, many people have built up a big library of high definition videos, and one of the complaints against VLC was the fact that all the inbuilt codecs relied completely on the CPU horsepower for decoding. Even the most powerful modern day multi-core processors have trouble decoding HD videos [Clarification: 'trouble' with CPU decoding might mean dropped frames, stutters, sudden spikes in CPU usage and kicking in of the CPU fan etc. These are more noticeable in single threaded decoder implementations].
HTPC users with GPUs capable of accelerating HD video decode initially relied on the bundled software (from Cyberlink / ArcSoft / Corel). However, the bloatware and container restrictions imposed by these players led enthusiasts to other open source projects such as Media Player Classic - Home Cinema (MPC-HC). These tapped into the GPU capabilities using DXVA / DXVA2 APIs on Windows and VAAPI on Linux. The extent of support provided in these APIs depended on the GPU vendor. Historically, Nvidia has provided much better support than ATI, while Intel was lagging behind for quite some time till late last year. This is evident from one of the popular blog posts used as a reference by people wanting to get DXVA working on their GPUs. Users of MPC-HC also had to deal with external codec packs such as CCCP. In addition, a large number of options had to be set up correctly in order to get GPU decoding to work. There was an urgent need for the big player in this space to come to the party, and Videolan has done that exactly with the 1.1.0 release of the VLC Media Player.
However, all is not well yet in VLC land. Videolan supplied the caveat that the experimental GPU acceleration would work only on Nvidia GPUs as of now. They cited troubles with the ATI drivers and the lack of access to a Intel IGP as the reason for not being able to support non-Nvidia platforms with confidence. With a core developer team of just 5 people, coupled with the fact that most of them are not Windows developers, it is hard to find fault with that reasoning.
At the end of our testing, we found out some unexpected good things. However, there was some disappointment as well. Before going into the details, let us take a look at the test bed and test suite we used for the analysis.
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Phynaz - Friday, June 25, 2010 - link
But I'm afraid this article is so full of misinformation that it should just be pulled.At least choose authors that are familiar with the subject they are writing about, as the author of this article knows next to nothing about digital video.
ganeshts - Friday, June 25, 2010 - link
Phynaz,Please do let me know what is wrong with the info in the article.
Most of it is based on personal testing of a variety of media on different systems, and a lot of information has been gleaned from actual interaction with a VLC developer.
I have no trouble with criticism, but it needs to be constructive. I am afraid your comments don't give me any insights into where I will need to improve.
Phynaz - Friday, June 25, 2010 - link
Others before me posted comments where the information in this article is just plain wrong. For example your statements that MPC requires codec packs for GPU accelerated decoding, or that modern cpu's have problems decoding HD video.Please post the specs of an i7 build that can't decode H.264 or VC-1 video without GPU assistance. Heck, a P4 could play H.264 with version 0.9 of VLC.
ganeshts - Friday, June 25, 2010 - link
There is absolutely no statement that MPC requires codec packs for GPU accelerated decoding.The original statements in the article are:
This is true if people wanted to play files not supported internally by MPC-HC such as Real Media and other arcane codecs. There also used to be a time when the internal Matroska splitter used in MPC-HC wasn't working properly, and Haali's splitter had to be used, which was again bundled with CCCP. :: I never talked about CCCP for GPU decode here.
This is true, since one had to set the renderer depending on the OS, and disable some internal filters. I have actually lost track of the number of options I played around with before I got DXVA to work with MPC-HC for the first time on my P4 with ATI 3450.
Onto your next point, modern CPU's have problems decoding HD video:
This is the exact quote:
The trouble decoding HD videos is when VLC is used ( and in testing on Windows XP, even when Windows Media Player is used - The WMP in Win7 actually uses the GPU (if available) and not the CPU for majority of the decoding.)
It is easy to say i7 build can decode H.264 or VC-1 without GPU assistance, but the important thing is not the spec of the build, but the spec of the stream (high definition - 1080p / 720p, bitrate - 10 Mbps / 50 Mbps? and so many other encoding characteristics).
In the playback performance section, I have indicated the specs of 3 modern day builds which spiked upto 100% CPU utilization for various H264 and VC1 streams.
By the way, my HTPC is a P4, and it couldn't keep up with playing HD H.264 using VLC. The key here is the HD moniker.
I don't wish to sound disrespectful, but am not sure how your misunderstanding of 4 simple lines in the article would (i) make the whole article full of misinformation, (ii) brand the author as not being familiar with what they are writing about and on top of that (iii) state that the author knows next to nothing about digital video ;
I will leave it to the rest of the readers to draw any conclusions in light of my above clarifications.
Mumrik - Friday, June 25, 2010 - link
People seem to have blind irrational loyalty towards MPC and it seems to distort their vision.I can't get myself to use either of these two regularly because of the horrible GUIs...
Touche - Saturday, June 26, 2010 - link
Although GUIs could use a little touchup, it really is the content that you are watching.kasakka - Sunday, June 27, 2010 - link
The GUI in MPC is rather old fashioned and VLC's GUI is not only crappy looking but also rather unintuitive especially in settings. VLC's skins help a bit but most of them seem to be somewhat incomplete too.It's truly a shame that many Windows developers seem to be very poor user interface designers, even though they may be wizards at things like codec development and whatnot.
jtleon - Tuesday, June 29, 2010 - link
I will second that - My own HTPC (P4 2Ghz laptop) cannot keep up with my home-made 720P (1280x720) HD videos that I have shrunk using VLC h.264 encoding to 1/10 their motion jpeg size. Now I am faced with upgrading the HTPC, or down-scaling my videos (not!).I have found the socket 754 Mobile Semprons (90nm, E-stepping) have absolutely no problem rendering h264 with VLC at HALF the P4 speed!
tlmaclennan - Friday, June 25, 2010 - link
I dropped VLC a long time ago for MPC-HC. Video quality is much better and I have the ability to bitstream via ffdshow. Most players support DXVA now, so sorry VLC but you're a bit too late.Wellsoul2 - Friday, June 25, 2010 - link
It would be interesting to see the test with a 3GHZ+ Quad core .For playing 720P and 1080P single music videos VLC seems to do fine already.
It tends to crap out after a few videos if you use the playlist feature...I don't know why..
I still use it alot and like it..so great if it's becoming better.