Sony, Panasonic Launch AVCHD
Is Panasonic Deviating from DVCPRO?
(click thumbnail)Panasonic AJ-HPC2000
At NAB2006, Panasonic announced the AJ-HPC2000, a multiformat 2/3-inch P2 HD camcorder with high-definition DVCPRO HD capability that is also backwards compatible with existing SD DVCPRO50, DVCPRO and DV-based products and systems.
Panasonic also said it will offer an optional plug-in professional H.264 compliant, "AVC-Intra" codec for the camcorder. This new AVC intraframe codec offers significantly better compression quality than older MPEG-2 codecs, providing DVCPRO HD 100 Mbps quality at half the bandwidth, or better quality at the same data rate.
However, the new codec is not backwards compatible with the DVCPRO HD codec. What would persuade Panasonic to leave the popular and profitable DVCPRO path?
According to Phil Livingston, Panasonic's technical liaison, if a new codec offered only a 10 or 20 percent improvement, "You'd say 'no thanks, I'm not interested. It's not enough gain in quality or enough savings in bitrate to derail the train.'
"But when you get to double, i.e. half the data rate or double the quality, now it's worth talking about bringing a new technology to market and suffering the difficulties of explaining why there are both."
Livingston doesn't expect the DVCPRO line to be gone any time soon.
"Understand... H.264 is just beginning to be supported by the nonlinear manufacturers-it's an emerging technology, where DVCPRO is well established and broadly supported. Everybody knows how to use it."
-- Craig JohnstonNew hi-def standard could be an effective competitor to HDV
Several weeks after NAB2006 shut its doors, the Japanese offices of broadcast equipment powerhouses Panasonic and Sony announced a new video format: AVCHD. "AVC" stands for Advanced Video Coding. You know what "HD" stands for.
Why wait until after the big show to roll it out? AVCHD is aimed at consumer DVD camcorders. But given the capabilities the new format brings, it wouldn't be surprising to see it follow the pathway of the DV format, which was originally touted for consumer level video cameras, then ended up being adapted all the way to high-definition.
For now, comparisons with AVCHD can be made against HDV, the other consumer or prosumer grade HD video format, which rolled out just a few years ago.
HDV records to tape. AVCHD records to 8 cm (about 3 1/4-inch) red laser DVDs. (Panasonic, in a separate announcement, said it is also developing solid-state SD-memory products for AVCHD.)
HDV compresses to and records at 25 Mbps. AVCHD compresses to and records at 18 Mbps.
Both are long-GOP, meaning their compression stretches out over several frames rather than each frame's compression being contained within the individual frame itself. (This has ramifications for editing, and generally means more rendering time.)
HDV is an MPEG-2 codec, while AVCHD is MPEG-4, Part 10, also known as H.264. (Sony's XDCAM format is MPEG-4, Part 2.)
Both can record at 1080i and 720p, though it is unlikely that all camcorders will be able to switch between the two.
Not to forget audio, AVCHD employs Dolby Digital or Linear PCM for an audio codec.
Nothing earth-shattering about the comparison between the two formats, so far. But then you get down to this line of the release: "The MPEG-4/H.264 codec is a promising technology which is over two times more efficient than MPEG-2 or MPEG-4 codec technologies."
While not singling out HDV in the release, the companies are saying that AVCHD is at least twice as efficient as HDV. At twice the efficiency, a simple math exercise would show that with its 18 Mbps encoding, AVCHD is 28 percent more efficient on the storage side, and that would still allow AVCHD to produce about a 70 percent increase in picture quality over HDV.
One key to the camcorder format is that it is designed for "red laser" 8cm DVDs, which are relatively cheap. The same size Blu-ray consumer data disks cost around $20 each. Both types of the new HD DVD players are expected to be able to playback AVCHD disks.
Sony and Panasonic also chose to use the MPEG-2 transport stream. Though it has nothing to do with the encoding, the MPEG-2 transport stream was chosen because modern digital TVs and set-top boxes already work with it.
PROS AND CONS-UMERS
Perusing Web postings about the new format, this writer found them generally impressed with AVCHD and predicting a quick demise of HDV. Among the comments were references to the fragility of DV-size tape as a recording media, and the problems with drop-out in an I-frame of the long-GOP encoding.
On the negative side, posters pointed out the one hour recording time of an HDV tape versus the approximately 20-minute recording time of the 8 cm red laser DVDs, and questioned the battery life of an AVCHD camcorder with its more computationally intensive encoding scheme.
Nonlinear editing vendors including Avid and Adobe are reported to be working to support AVCHD. To the extent they've developed technology to handle the long-GOP issues with HDV, that technology should be applicable to AVCHD's long-GOP as well.
At this writing, none of the other camcorder manufacturers TV Technology contacted have announced plans for an AVCHD camcorder, though the joint Sony and Panasonic announcement notes: "The two companies have started preparations for licensing to extensively promote the format throughout the industry."
One representative from Panasonic's professional division did weigh in his reservations over the use of AVCHD for professional video production.
"If you buy into our position that HDV is not at a level that a professional would want to shoot at, because of the amount of compression involved, then yes, I would say that this follows that same philosophy," said Phil Livingston, Panasonic's technical liaison.
Toward that end, Panasonic introduced an option for its new AJ-HPC2000 P2 HD camcorder to allow it to encode with the MPEG-4/H.264 codec, but at 50 Mbps. This places it on a par with the company's DVCPRO HD, encoding at 100 Mbps. (See accompanying story.) A Sony spokesman said the company currently has no plans to incorporate AVCHD technology into its professional video camcorder product line for broadcast and production.
So is AVCHD going to end up following DV's path to become a full-fledged professional video format? It's still early in the game.
"The reason this is all taking time to roll out is that for the H.264 compression standard, in relative terms, the ink is just getting dry," said Livingston.
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