HD Video Playback: H.264 Blu-ray on the PC

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.