H.264 'Decoded'
QuickTime 7, released under Tiger - Apple's new operating system, includes a video codec called H.264. H.264 is the next-generation video compression technology in the MPEG-4 standard, also known as MPEG-4 Part 10.
H.264 is a scalable codec; it is designed to deliver high quality video across the entire bandwidth spectrum 'from 3G to HD and everything in between' (from 40 Kbps to upwards of 10 Mbps).
In other words whether your target platform is a mobile device, the web or next generation DVD, H.264 is an efficient codec for distribution purposes.
H.264 will also provide the basis for applications such as video conferencing, video-on-demand, streaming and multimedia messaging. But it is as a method for carrying HD video on the next generation of DVDs that H.264 will make its mark.
Currently the two incompatible and competing specifications, HD-DVD and Blu-Ray, are vying to become the prevailing format for carrying Hi Def video to the consumer.
H.264 is an integral part of each of these formats. No matter which prevails (and there is still talk of a 'merger'), the codec H.264 is sure to be supported.
Apple claims that H.264 delivers the same quality as MPEG-2 at a third to half the data rate and up to four times the frame size of MPEG-4 Part 2 at the same data rate.
In essence this means we can encode SD video at half the data rate previously, or more interestingly we can encode HD video at around the same data rate as we encoded SD video previously.
Speaking of data rates, here are some example H.264 rates across the bandwidth spectrum:
Full HD at 1920 x 1080 pixels at a progressive frame rate of 24fps would be encoded at around 7-8Mbps using H.264.
Moving down the scale, 720p would be encoded at around 5-6Mbps.
Further down the scale, an SD resolution piece (720 x 576 pixels) would be encoded at around 1-2Mbps. This would provide video just about distributable over the Internet.
And lastly H.264 can support the superslim bandwidth demands of 3G mobile networks, producing video encoded at around 50-60Kbps at 176 x 144 pixels/10-24 fps.
Those of us then who use the Macintosh to cut HD now have the opportunity to encode our finished pieces whilst retaining HD pixel resolution, and what's more, in terms of size, the resultant files will be more than manageable.
Here in 'the lab' we're currently playing around with Compressor, trying to get the best out of H.264, encoding material shot on HDCAM as well as HDV, so watch this space, we'll post it soon.
The only slight hitch for those wanting to view H.264 encoded video at HD resolution, is that you'll need a higher end mac in order to do it. Apple recommends a minimum G5/1.8GHz system or better to play back HD-quality QuickTime videos and movie trailers, for example. In fact most computers (PC & Mac) will probably not be fast enough to decode H.264 at true HD resolution via software, and will likely rely on a graphics card with that capability. ATI amongst others will no doubt produce them.
Eventually though, increases in the power and speed of CPUs will mean over time that decoding H.264 will migrate towards becoming a software-only task.