Great Editorial About AVCHD H.264/MPEG-4 vs. Other HD Formats

[Jerry Jones]

http://tinyurl.com/nvvtd

The opinion piece is written by Wayne Cole for GOVERNMENT VIDEO Magazine.

AVCHD uses MPEG-4 AVC/H.264 compression and encoding for video recording. HDV, on the other hand, uses MPEG-2 Main Profile @ High-1440. Anyone who has compressed an HD video feed to H.264 and to MPEG-2 High-1440 at the same bit rate will tell you that the H.264 version is noticeably better. And this is the first "rub" to HDV users -- AVCHD uses an almost identical data rate (24 Mbps) -- in an MPEG-2 transport stream wrapper. There are other video advantages in the AVCHD format. For example, it allows for 16:9 aspect ratio pictures in HD with a raster size of 1920x1080 in addition to the HDV raster sizes of 1440x1080 and 1280x720. At the larger raster size, AVCHD has the potential to produce higher horizontal resolution than HDV. AVCHD recording supports 1080i/24/50/60, as well as 720p/24/50/60. Plus, the new format supports 16:9 and 4:3 SD raster sizes of 720x480 at 60i (NTSC) and 720x576 at 50i (PAL). Digging a little deeper into the two specs, AVCHD has an advantage over HDV in luminance sampling of 1080 video. With the 1920x1080 raster, AVCHD uses a luminance sampling frequency of 74.25 MHz, compared to HDV's 55.7 MHz. In HDV, the higher luminance sampling frequency is reserved for its 720p recording modes, which may explain why 720p HDV can show higher horizontal resolution than 1080i HDV. When AVCHD is set to use the 1440x1080 raster, however, it appears that the standard requires the use of 55.7 MHz luminance sampling, and that will limit AVCHD's advantage solely to the superiority of H.264 encoding. AVCHD calls for audio recording Dolby AC-3 for one channel or up to 5.1 channels, with data rates from 64 kbps to 640 kbps, or in PCM up to 7.1 at 1.5 Mbps per 2 channels. HDV is limited to two channels of audio compressed with MPEG-1 layer II to 384 kbps. The difference in audio specs might be a giveaway as to why yet another "consumer" HD format has been introduced.

And this:

As long as HDV, XDCAM-HD, and DVCPRO HD equipment continues to capture the imagination of lower-cost HD producers and facilities, it's likely that Sony and Panasonic will use their AVCHD licensing clout to ensure that no "AVCHD-Pro" equipment ever comes to market. On the other hand, if Grass Valley implements direct H.264 recording to REV PRO disks in its Infinity Digital Media Camcorder, and it begins to cut significantly into the XDCAM HD or DVCPRO HD market share, Sony and Panasonic would be able to quickly counter with 1/2-inch and 2/3-inch CCD units using almost the same AVCHD encoders as their consumer units, but perhaps with higher data rates (and milder compression levels).

GRASS VALLEY's interesting "RevPro" Web site:

http://tinyurl.com/z2v2a

GRASS VALLEY's "Infinity" camcorder:

http://tinyurl.com/jdncs

Jerry Jones

http://www.jonesgroup.net

[Jerry Jones]

Also this:

The Blu-ray camp may be able to sabotage HD-DVD by having the first HD optical disc burners and media in the market, a possibility that seems very likely. But with the motion picture industry's paranoia driving the incorporation of technical copy protection implementation details by Congress in the laws governing the production and sale of HD optical disc players, recorders, and HD displays, manufacturers had to create something to make Blu-ray recording equipment and media attractive to John Q. Public. Enter AVCHD camcorders with IEEE-1394 and USB 2 ports. With companies like Ulead, Adobe, Sonic, Nero, and InterVideo signed up to support AVCHD, it seems clear that the idea is to allow consumers to burn their own AVCHD videos direct to Blu-ray discs. The audio and video specs of AVCHD match up perfectly with one of the formats specified for Blu-ray. With HDV, on the other hand, there would need to be a transcoding step (MPEG-2 to H.264) involved that might be beyond the capability and tool set of the average consumer. The prospect that consumers may be able to record better quality HD with equipment that costs less than professional HDV equipment has some industry observers scratching their heads. If you don't see AVCHD as the mechanism to support and perhaps make Blu-ray the dominant consumer optical video disc format, then it almost looks to be a competitor to HDV and possibly even XDCAM HD. However, the CCD and optics used on most HDV camcorders will allow HDV to hold its own at least against early AVCHD camcorders.

http://tinyurl.com/nvvtd

Jerry Jones

http://www.jonesgroup.net