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MillimeterWhat's in a name: H.264
Jun 23, 2005 5:39 PM, D. W. Leitner
MPEG-4 is a family of compression technologies making its presence felt these days after a long and bumpy gestation.
Recent MPEG-4 products from MPEG trailblazer Sony include videoconferencing, security cameras, PlayStation Portable, and HDCAM SR, the 4:4:4, 440 Mbps tape format George Lucas used to originate Return of the Sith.
While prior art in MPEG-4 compression is known as MPEG-4 Part 2, shaping up to be the most popular MPEG-4 compression—what MP3 is to MPEG-1—is "next-generation" MPEG-4 Part 10.
Also called H.264 (pronounced H "dot" 264). Or, if you’d like, H.26L, ISO/IEC 14496-10, JVT, or MPEG-4 AVC.
More aliases than a witness protection program? No, a testament to the welter of standards groups that joined forces to cobble together this state-of-the-art compression 2-3 times more efficient than MPEG-2.
In 1998, the Video Coding Experts Group (VCEG) of the International Telecommunication Union (ITU-T) began a project to improve efficiencies of video compression, an effort joined in 2001 by the Moving Pictures Experts Group (MPEG) of the joint International Organization for Standardization/International Electrotechnical Commission (ISO/IEC). The fruit of this "Joint Video Team" (JVT) was a new MPEG-4 standard, ITU-T H.264, announced May, 2003.
The simplest tag for this most powerful of modern video compressions would be AVC, for Advanced Video Coding. However "H.264" has that je ne sais quoi, that certain ring to it, at least to the ears of marketing mastermind Steve Jobs.
Apple contributed significantly to the evolution of MPEG-4, originally modeled after QuickTime, and has positioned H.264 as jewel in the crown of QuickTime 7, which debuted in April at NAB. So given Apple's prowess at promotion, all bets are that the ITU’s cryptic nomenclature, H.264, will gain traction with the public.
Here are three things you need to know about H.264:
1) No backward compatibility with MPEG-2. This is new technology, taking full advantage of the latest, most advanced coding techniques.
2) Extensive scalability for an unprecedented range of uses, from low-bitrate IPTV (Internet Protocol TV) via DSL or cell phones to terrestrial/cable/satellite broadcasting; from teleconferencing and streaming to video-on-demand; from hard disk storage and high-definition DVDs to high-bitrate digital cinema. An EBU (European Broadcasting Union) committee is presently evaluating H.264 for HD broadcasting in Europe, since it reduces HDTV data rates by 50%.
3) Last-minute additions to the H.264 standard in 2004 (called fidelity range extensions or FRExt) established a new set of High profiles supporting up to 4:4:4 chroma sampling at 12 bits per sample and coding efficiencies up to 3:1 over previous compression technologies. H.264 High profiles have since been incorporated into both the DVD Forum’s HD-DVD specification (read only) and competing BD-ROM specification of the Blu-ray Disc Association.
The aforementioned EBU committee looking into compression for HD broadcasting is also considering a competing high-efficiency codec that reduces HDTV data rates by 50%, Windows Media 9.
WM9 first made a splash in 2003, with fancy launches including the Sundance Film Festival, where it was touted as a vehicle for Indie film delivery.
Criticized at first as closed Microsoft technology, WM9 was submitted that same year to SMPTE to establish its bitstream structure and syntax as a standard, thereby encouraging others to create their own encoders. Microsoft's strategy paid off when SMPTE standardized WM9 as VC-1, as it is now formally known. (VC for video compression.) Standardization somewhat undercut the criticism that unlike H.264, WM9 was not an open standard.
The exciting thing about H.264 and VC-1 is that, while HD-DVDs will soon offer 15 GB per side (backward compatible with conventional DVD) and Blu-ray, 25 GB (not DVD-compatible) for HD playback of Hollywood movies, either H.264 and VC-1 already can fit an entire HD movie (1920x1080, 24 fps) at 7-9 Mbps on today’s conventional DVD. Which looks pretty darn good, by the way.
Or—also today—you can watch Steve Jobs drop the bomb that he's a "switcher" to Intel at Apple's recent World Wide Developers Conference. In HD, via H.264 streaming, using Apple’s free QuickTime 7 Player for Windows or Mac. You’ll find both software and media links at Apple's website.
Continue the discussion on “Crosstalk” the Millimeter Forum.