D3 video

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Panasonic D3-VTR AJ-D350
Panasonic D3-VTR AJ-D350
A Cassette Tape for D3-VTR(Medium)
A Cassette Tape for D3-VTR(Medium)

D3 is an uncompressed composite digital video tape format invented at NHK, and introduced commercially by Panasonic in 1991 to compete with Ampex's D2. It uses half-inch metal particle tape at 83.88mm/s (compare to D2's 19mm and 131.7mm/s). Like D2, the video signal is sampled at four times the color subcarrier frequency, with eight bits per sample. Four channels of 48khz 16-20 bit PCM audio, and other ancillary data, are inserted during the vertical blanking interval. The aggregate net (error corrected) bitrate of the format is 143mbps, and because the codec is lossless, it has been used in data applications. Camcorders were available which used this format, and are to date the only digital tape camcorders to use a lossless encoding scheme. The D5 format, introduced in 1993 by Panasonic and presently (2006) marketed as D5 HD, uses the D3 transport and tape running at roughly double D3 speed. The D3 transport in turn is derived from the MII transport. D3/D5 tapes come in small (161mm X 96mm X 25mm), medium (212mm X 124mm X 25mm), and large (296mm X 167mm X 25mm) cassettes, with format-specific recognition holes. Maximum D3 runtimes (in the Fujifilm lineup) are 50, 126, and 248 minutes respectively.

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