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.

H.264 Encoded HD Content: A Good Thing
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  • charleski - Tuesday, December 19, 2006 - link

    The only conclusion that can be taken from this article is that PowerDVD uses a very poor h.264 decoder. You got obsessed with comparing different bits of hardware and ignored the real weak link in the chain - the software.

    Pure software decoding of 1080-res h.264 can be done even on a PentiumD if you use a decent decoder such as CoreAVC or even just the one in ffdshow. You also ignored the fact that these different decoders definitely do differ in the quality of their output. PowerDVD's output is by far the worst to my eyes, the best being ffdshow closely followed by CoreAVC.
    Reply
  • tronsr71 - Friday, December 15, 2006 - link

    The article mentions that the amount of decoding offloaded by the GPU is directly tied into core clock speed (at least for Nvidia)... If this is true, why not throw in the 6600GT for comparison?? They usually come clocked at 500 mhz stock, but I am currently running mine at 580 with no modifications or extra case cooling.

    In my opinion, if you were primarily interested in Blu-Ray/HD-DVD watching on your computer or HTPC and gaming as a secondary pastime, the 6600GT would be a great inexpensive approach to supporting a less powerful CPU.

    Derek, any chance we could see some benches of this GPU thrown into the mix?
    Reply
  • balazs203 - Friday, December 15, 2006 - link

    Could somebody tell me what the framerate is of the outgoing signal from the video card? I know that the Playstation 3 can only output a 60 fps signal, but some standalone palyers can output 24 fps. Reply
  • valnar - Wednesday, December 13, 2006 - link

    From the 50,000 foot view, it seems just about right, or "fair" in the eyes of a new consumer. HD-DVD and BluRay just came out. It requires a new set-top player for those discs. If you built a new computer TODAY, the parts are readily available to handle the processing needed for decoding. One cannot always expect their older PC to work with today's needs - yes, even a PC only a year old. All in all, it sounds about right.

    I fall into the category as most of the other posters. My PC can't do it. Build a new one (which I will do soon), and it will. Why all the complaining? I'm sure most of us need to get a new HDCP video card anyway.
    Reply
  • plonk420 - Tuesday, December 12, 2006 - link

    i can play a High Profile 1080p(25) AVC video on my X2-4600 at maybe 40-70 CPU max (70% being a peak, i think it averaged 50-60%) with CoreAVC...

    now the ONLY difference is my clip was sans audio and 13mbit (i was simulating a movie at a bitrate if you were to try to squeeze The Matrix onto a single layer HD DVD disc). i doubt 18mbit adds TOO much more computation...
    Reply
  • plonk420 - Wednesday, December 13, 2006 - link

    http://www.megaupload.com/?d=CLEBUGGH">http://www.megaupload.com/?d=CLEBUGGH

    give that a try ... high profile 1080p AVC, with all CPU-sapping options on except for B-[frame-]pyramid.

    it DOES have CAVLC (IIRC), 3 B-frames, 3 Refs, 8x8 / 4x4 Transform
    Reply
  • Spoelie - Friday, April 20, 2007 - link

    CABAC is better and more cpu-sapping then CAVLC Reply
  • Stereodude - Tuesday, December 12, 2006 - link

    How come the results of this tests are so different from http://www.pcper.com/article.php?aid=328&type=...">this PC Perspective review? I realize they tested HD-DVD, and this review is for Blu-Ray, but H.264 is H.264. Of note is that nVidia provided an E6300 and 7600GT to them to do the review with and it worked great (per the reviewer). Also very interesting is how the hardware acceleration dropped CPU usage from 100% down to 50% in their review on the worst case H.264 disc, but only reduced CPU usage by ~20% with a 7600GT in this review.

    Lastly, why is nVidia http://download.nvidia.com/downloads/pvzone/Checkl...">recommending an E6300 for H.264 blu-ray and HD-DVD playback with a 7600GT if it's completely inadequate as this review shows?
    Reply
  • DerekWilson - Thursday, December 14, 2006 - link

    HD-DVD movies even using H.264 are not as stressful. H.264 decode requirements depend on the bitrate at which video is encoded. Higher bitrates will be more stressful. Blu-ray disks have the potential for much higher bitrate movies because they currently support up to 50GB (high bitrate movies also require more space). Reply
  • balazs203 - Wednesday, December 13, 2006 - link

    Maybe the bitrate of their disk is not as high as the bitrate of that part of XMEN III.

    I would not say it completely inadequate. According to the Anandtech review the E6300 with the 8800GTX could remain under 100% CPU utilisation even under the highest bitrate point (the 8800GTX and the 7600GT had the same worst case CPU utilisation in the tests).
    Reply

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