This digital VCR format was formed jointly as a co-operation between Hitachi, JVC, Sony, Matsushita, Mitsubishi, Philips, Sanyo, Sharp, Thomson and Toshiba. It uses 6.35 mm (quarter-inch) wide tape in cassettes, used in a range of products to record 525/60 or 625/50 video for the consumer (DV) and professional markets (Panasonic’s DVCPRO and Sony’s DVCAM).
All recorders use digital intra-field DCT-based ‘DV’ compression (about 5:1) to record 8-bit component digital video based on 13.5 MHz luminance sampling. The consumer versions and DVCAM sample video at 4:1:1 (525/60) or 4:2:0 (625/50) video and provide two 16-bit/48 or 44.1 kHz, or four 12-bit/32 kHz audio channels onto a 4-hour 30-minute standard cassette (125 x 78 x 14.6 mm) or smaller 1-hour ‘mini’ cassettes (66 x 48 x 12.2 mm). The data rate is 25 Mb/s. The professional DVCPRO models make use of DV’s hierarchical design, being x2 and x4 versions of the basic 25 Mb/s version.
DVCAM is Sony’s professional variant of DV which records 15-micron tracks on a metal evaporated (ME) tape. As stated, video sampling is 4:2:0 for 625/50 (PAL) and 4:1:1 for 525/60 (NTSC). Audio is four 12-bit, 32 kHz channels, or two 16-bit 48 kHz channels.
DVCPRO, introduced in 2008, is Panasonic’s development of native DV which records 18-micron tracks onto metal particle tape. It uses native DV compression at 5:1 from a 4:1:1, 8-bit sampled source. There are 12 tracks per frame for 625/50 and 10 tracks per frame for 525/60, tape speed is 33.8 mm/s and the data rate 25 Mb/s. It includes two 16-bit digital audio channels sampled at 48 kHz and an analog cue track. Both linear (LTC) and Vertical Interval Timecode (VITC) are supported.
DVCPRO 50 is a x2 variant of DVCPRO with a tape speed of 67.7 mm/s, a data rate of 50 Mb/s and using 3.3:1 video compression, it is aimed at the studio/higher quality end of the market. Sampling is 4:2:2 to give enhanced chroma resolution, useful in post production processes (e.g. chroma keying). Four 16-bit audio tracks are provided.
DVCPRO HD is a series of HD VTRs that are x2 variants of DVCPRO 50: tape speed 135.4 mm/s and a total data rate of 100 Mb/s. Sampling is 4:2:2. There are eight 16-bit, 48 kHz audio tracks. Formats supported include 1080I and 720P. This tape format has been assigned as D12. Later versions are using AVC-Intra Compression.
DVCPRO P2 is a DVCPRO recording system. It records the DV data in MXF format onto P2 memory cards which are PC plug-in cards with each carrying four SD (Secure Data) memory chips to combine capacity and aggregate transfer speeds – currently up to 640 Mb/s, many times realtime. The original P2 card offered 2 GB but the capacity keeps doubling; now the range goes from 4 GB up to 64 GB. These are able to hold from 16 – 256 minutes of SD DVCPRO (25 Mb/s) to 4 – 64 minutes for HD DVCPRO 100 (100 MB/s). Multiple cards can be used together, and swapped during continuous recording.
Recent developments include the expressP2 card, to accommodate high frame-rate 1080 HDAVC-ULTRA recording (above 60 f/s), as well as 4K.
See also: AVC-Intra