HD Video Playback: H.264 Blu-ray on the PC
by Derek Wilson on December 11, 2006 9:50 AM EST- Posted in
- GPUs
Introduction
In November, we published our first article featuring Blu-ray content. While we focused more on the capability of the cards we tested to play digital content protected with HDCP, we did take a preliminary look at hardware accelerated high definition video playback with the movie Click.
Our first glimpse of the processing power required to play HD content on the PC gave us a very good indication that Blu-ray movies using MPEG-2 should have no problem on a modern system, even without GPU acceleration. The Core 2 Duo E6300 is easily capable of playing back 50-60 Mbps MPEG-2 video at 1080p. Adding a GPU to the mix did make an impact, but the small boost in performance just wasn't necessary.
Today we will turn the tables around and look at what happens when H.264/MPEG-4 AVC meets Blu-ray on the PC. This combination is much more demanding than MPEG-2 encoded Blu-ray movies, as H.264 is capable of much higher compression at better quality which requires more processing power.
Before we get to our results, it is important to talk a bit about playback of HD media on the PC. BD and HDDVD movies are copy protected with AACS which uses HDCP to encrypt and decrypt the video signal when it's sent over a digital connection. In order to view one of these movies on an HDTV over either a DVI or HDMI connection, an HDCP enabled video card is required.
All video cards that have an HDMI connection on them should support HDCP, but the story is different with DVI. Only recently have manufacturers started including the encryption keys required for HDCP. Licensing these keys costs hardware makers money, and the inclusion of HDCP functionality hasn't been seen as a good investment until recently (as Blu-ray and HDDVD players are finally available for the PC). While NVIDIA and ATI are both saying that most (if not all) of the cards available based on products released within the last few months will include the required hardware support, the final decision is still in the hands of the graphics card maker.
It is important to make it clear that HDCP graphics cards are only required to watch protected HD content over a digital connection. Until movie studios decide to enable the ICT (Image Constraint Token), HD movies will be watchable at full resolution over an analog connection. While analog video will work for many current users, it won't be a long term solution.
Now that we've recapped what we know about watching HD content on the PC, lets take a look at why things will be a little different now that H.264/MPEG-4 AVC encoded movies are here.
In November, we published our first article featuring Blu-ray content. While we focused more on the capability of the cards we tested to play digital content protected with HDCP, we did take a preliminary look at hardware accelerated high definition video playback with the movie Click.
Our first glimpse of the processing power required to play HD content on the PC gave us a very good indication that Blu-ray movies using MPEG-2 should have no problem on a modern system, even without GPU acceleration. The Core 2 Duo E6300 is easily capable of playing back 50-60 Mbps MPEG-2 video at 1080p. Adding a GPU to the mix did make an impact, but the small boost in performance just wasn't necessary.
Today we will turn the tables around and look at what happens when H.264/MPEG-4 AVC meets Blu-ray on the PC. This combination is much more demanding than MPEG-2 encoded Blu-ray movies, as H.264 is capable of much higher compression at better quality which requires more processing power.
Before we get to our results, it is important to talk a bit about playback of HD media on the PC. BD and HDDVD movies are copy protected with AACS which uses HDCP to encrypt and decrypt the video signal when it's sent over a digital connection. In order to view one of these movies on an HDTV over either a DVI or HDMI connection, an HDCP enabled video card is required.
All video cards that have an HDMI connection on them should support HDCP, but the story is different with DVI. Only recently have manufacturers started including the encryption keys required for HDCP. Licensing these keys costs hardware makers money, and the inclusion of HDCP functionality hasn't been seen as a good investment until recently (as Blu-ray and HDDVD players are finally available for the PC). While NVIDIA and ATI are both saying that most (if not all) of the cards available based on products released within the last few months will include the required hardware support, the final decision is still in the hands of the graphics card maker.
It is important to make it clear that HDCP graphics cards are only required to watch protected HD content over a digital connection. Until movie studios decide to enable the ICT (Image Constraint Token), HD movies will be watchable at full resolution over an analog connection. While analog video will work for many current users, it won't be a long term solution.
Now that we've recapped what we know about watching HD content on the PC, lets take a look at why things will be a little different now that H.264/MPEG-4 AVC encoded movies are here.
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DerekWilson - Monday, December 11, 2006 - link
cool -- we'll have to investigate this.liquidaim - Monday, December 11, 2006 - link
Did you use the 3d clocks for ati cards or the normal 2d?Just wondering if that was taken into account for the MPEG-2 tests previously and not here, which is why ati cards didn't perform as well.
Not a fanboy, just asking for clarification.
DerekWilson - Monday, December 11, 2006 - link
I don't believe you can specify what clock ATI uses when decoding video -- I think this is handled internally. It may be that the hardware that helps accelerate MPEG-2 the most is tied to clock, while the majority of what benefits H.264 is not. We'll have to dig further to really know.pata2001 - Monday, December 11, 2006 - link
It was the same thing when MPEG2 came out. Heck, even in the old days of 386s, PCs are too slow to decode MPEG1 VCDs, to the point that we have a seperate MPEG1 decoder cards. Remember when DVD came out, there was a big push for GPU accelerated hardware iDCT. Today, most CPUs are powerful enough to decode MPEG2 on its own. The same thing agian with MPEG4. By the time 4-core/8-core CPUs become mainstream, we won't be hearing the need for GPU acceleration as much anymore. And by that time, there will be probably the next next gen HD format that is too powerful for CPUs for that time, cycle and repeat.DerekWilson - Monday, December 11, 2006 - link
MPEG-4 contains many advanced features not currently in use. We first saw MPEG-4 part 2 in the form of DivX, but MPEG-4 part 10 takes quite a bit more work. Some of the profiles and levels of H.264/AVC will be too much for quad core CPUs to handle. These may not be adopted by studios for use on physical media, but the codec itself is very forward looking.But in the end, you are correct -- the entire MPEG-4 spec will be a simple matter in a handful of years.
This is the case with everything though. Even if something will one day pose no trouble to computers, we can't ignore current performance. Studios must balance current performance with the flexibility to support the type of image quailty they will want near the end of the life cycle of BD and HDDVD formats.
I always look forward to this kind of thing, and it's why I test hardware -- I want to know what my PC can currently do with what is out there.
I suppose the "news" is that we've got something everyone wouldn't mind having that very few will be able to use for the time being.
Staples - Monday, December 11, 2006 - link
This is good news that MPEG2 won't become the standard for BD. Until today, I figured all movies were in MPEG2 and if this became standard and won the format war, we would be stuck with what could arguably give a worse picture than HDDVD using VC1.How do you know what movies are 50gb and or h264? Does it usually say on the box or does the player tell you?
DerekWilson - Monday, December 11, 2006 - link
In our experience with Blu-ray, the format is listed on the box. HDDVDs have been a little more cryptic and we are having to ask for help determining format.For our X-Men BD, the back of the case stated AVC @18 Mbps.
I don't think disk size has been listed on the case, and we've had to ask for this info from industry sources.
CrystalBay - Monday, December 11, 2006 - link
Are AMD X2's unable to efficiently work in these scenarios ?DerekWilson - Monday, December 11, 2006 - link
AMD CPUs will very likely perform worse than Core 2 Duo CPUs.We are considering doing a CPU comparison.
Xajel - Monday, December 11, 2006 - link
IT's logical to be worse, but most users are using these processors and they really wanna know if there rig's can handle it...it's not about AMD only, there's plenty of Pentium 4, Pentium D in these rigs, even Athlon XP still rocks in some..
what about core scaling test ?? I mean
1- Single Core
2- Single Core with Hyper Threading
3- Two Cores
4- Two Cores with Hyper Threading
5- Four Cores
it will be hard to do this scale as they are not from one arch. ( 1 to 4 are NetBurst with Pentium 4, Pentium D, Pentium EE while the last is Core Arch. )