a) Tape width is 1/4", metal particle formula.

The source and reconstructed video sample rate is similar to that of CCIR-601, but with additional chrominance subsampling (4:1:1 in the case of 30 Hz and 4:2:0 in the case of 25 Hz mode). For 30 frames/sec, the active source rate is 720 pixels/lines x 480 lines/frame x 30 frames/sec x 1.5 samples/pixel average x 8 samples/pixel = ~124 Mbit/sec. A JPEG-like still image compression algorithm (with macroblock adaptive quantization) applied with a 5:1 reduction ratio (target bit rate of 25 Mbit/sec) averaged over a period of roughly 100 microseconds (100 microseconds is pretty small compared to MPEG’s typical 1/4 second time average!) b) A digital tape recording format using approximately 5:1 compression to produce near-Betacam quality on a very small cassette. Originated as a consumer product, but being used professionally as exemplified by Panasonic’s variation, DVC-Pro.