Features

The Roots of HDV

Now that television broadcasters and manufactures have managed to make high-definition both available and relatively affordable, the video production market is increasingly moving to digital video. Although there are several high-definition standards, High Definition Video (HDV) is showing the most potential as a format that could satisfy both professionals and consumers.

HDV got is start late last year when the four largest video camera manufacturers, Canon, Sharp, Sony, and JVC, signed on to support a common standard. (Panasonic was the only major industry holdout.) The key advantage of HDV is that it supports the recording and playback of high-definition video on a DV cassette tape.

The HDV format includes 720p (progressive) and 1080i (interlace) specifications, and enables the development of products conforming to the global high-definition infrastructure. The 720p specifications in the HDV format are the same specifications as adopted in the GR-HD1 high-definition digital video camera that JVC introduced in March, 2003. By adopting both the 720p and the 1080i specifications, the HDV format will enable users to record high-definition video and play it on their HDTV sets.

Fitting all of that data on a standard DV cassette isn't easy, but it enables vendors to create a variety of user-friendly form factors. The HDV format specifies the data recording of MPEG2 compressed high-definition signals based on the DV format, which is internationally accepted as a consumer digital VCR format. Because the new format employs the same cassette case, tape speed, and track pitch as the DV format, it can use mechanical parts based on the DV format. It also makes it easy for manufacturers to develop products that are compatible with the DV format.

The HDV format records both video and audio through compression by MPEG encoding. Video signals are compressed by MPEG2 encoding (inter-frame compression) as BS digital broadcasting, making possible the recording and playback of high-definition video at a bit rate equivalent to the DV format SD (standard definition) specifications (intra-frame compression.) Audio signals are digitized with a 48kHz/16-bit sampling frequency and compressed to 384kbps by MPEG1 Audio Layer II encoding.

The HDV format also delivers improved error correction and special playback features. For example, by changing the error correction method from error correction within a track, as specified in the DV-SD format, to error correction among multiple tracks, the HDV format offers improved error correction capability and enhanced resistance to lost data caused by dropout. The HDV format also records specific data for special playback on a dedicated tape, enabling the display of video images during special playback such as fast search or slow-motion playback.

High Definition, Low Cost

JVC was the first company to bring HDV cameras to market, when it released the professional-class JY-HD10U and consumer-level GR-HD1 last year. Previously, HDTV camcorders cost well over $50,000, putting them out of the price range of most videographers.

The $3,000 JY-HD10U single-CCD system that lets you record high definition native 16:9 content in the 1280 x 720P mode at 30 frames per second. Recordings are stored on standard Mini-DV cassettes that can store 63 minutes recording time per cassette. You can play them back directly from the JY-HD10U camcorder onto an HDTV monitor or projector with component inputs, or dub them to JVC D-VHS machines using the IEEE-1394 interface.

The JY-HD10U can also be used to make 16:9 progressive scan recordings in the 480/60P mode--ideal for viewing on today's high quality DVD players. The camera can also make standard 480i recordings in the Mini-DV format compatible with a wide range of systems. JVC uses the industry's open-standard MPEG-2 data format--the same that's used by broadcasters to transmit HD to millions of American homes.

Sony is also poised to jump into the HDV market. Sony has previewed a prototype of a three CCD HDV video camera at CeBit in Hanover Germany and at the National Association of Broadcasters conference in Las Vegas, NV. Although information on the device is scarce, a few details can be gleaned from the company's press releases and the photo it released.