Originally Posted by scowl
Heavens, even HD-DVD and BluRay players can go way past that bitrate and they're still extremely compressed formats.
Doesn't D5 use lossless compression of something like 4:1 in a 4:2:2 color space? I was thinking we might as well keep the whole 4:4:4 color space since I'm not paying for it.
D5 is not loss-less for HD material, as you say it uses around 4:1 compression of a 4:2:2 uncompressed source, and this isn't lossless, though it is very high quality.
D5 IS lossless for SD material (13.5MHz 10bit 270Mbs or 18MHz 8bit 270Mbs uncompressed 4:2:2) - and the HD-D5 format was effectively created by tacking on an external compression unit that 4:1 compressed a 4:2:2 HD-SDI 1080i or 720p source down to 270Mbs, allowing this to be recorded on tape. (A similar system was also developed for the earlier D1 uncompressed SD VTRs but D1 was already an aging, expensive and less practical tape format by this time)
The only uncompressed VTR for HD that I know of is the BTS/Philips and Toshiba D6 (aka Digital Voodoo) HD VTR - and this is also pretty obsolete these days.
Back of envelope calculation, assuming you only store the active picture content of a 1080p or 1080i frame :
1080x1920 pixels at 4:2:2 colour space with 8 bit depth would be :
1080x1920x16 bits, or 1080x1920x2 bytes per frame
This is approx 3.96 Megabytes per frame
So for 24fps (24p) that would be 95 Megabytes per second, for 25fps (25p or 50i) 99 Megabytes per second, and for 30fps (30p or 60i) 119 Megabytes per second.
Let's take 1080/60i, as that is probably the format whizzing down your HDMI link to your TV.
In 60 seconds that would be 6.95 Gigabytes (assuming 1024 Megabytes to the gigabyte - which hard drive manufacturers don't usually, and instead use 1000...), which would mean in an hour it would be around 417 Gigabytes?
So for a 4:2:2 YCrCb 1080/60i or 1080/30p video feed - assuming you only record the active 1920x1080 frame - you end up with around 420Gb per hour? This isn't quite the same as losslessly recording the HDMI or HD-SDI digital video stream - as you aren't recording any data that might be carried in vertical or horizontal blanking.