Messages in this thread | | | Subject | Re: reverse engineering pwcx | From | Lee Revell <> | Date | Sat, 28 Aug 2004 14:08:51 -0400 |
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On Sat, 2004-08-28 at 14:04, Lee Revell wrote: > On Sat, 2004-08-28 at 13:53, Joel Jaeggli wrote: > > On Sat, 28 Aug 2004, Lee Revell wrote: > > > > > > How do you account for the Slashdot poster's assertion that it's > > > physically impossible to cram 640 x 480 worth of data down a USB 1.1 > > > pipe? > > > > 640x480 = 307200 pixels > > x 24 bits = 7372800 bits per frame (.9MB) > > x 30 fps = 221184000 > > > > so that's 221mb/s for uncompressed 640x480. dv with 16bit pcm is 25Mb/s > > typically which is still a bit more than double what you can reasonably > > push through a usb1.1 port. raw you can push about 1.6 fp/s at 640x480 > > through usb so your compression ratio needs to be order of 15 to 1 make > > it fit reasonably with room for overhead. > > 15 to 1 is impossible without lossy compression.
Disregard, Vojtech's post clears things up.
Lee
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