#Where is PCI capture??
11-Feb-95 17:34:56
Sb: #2536-#Where is PCI capture??
Fm: Jan Bottorff 74775,546
To: Robb Olsen 73373,2562
I can think of 2 PCI capture cards. One from somebody like ThunderVision, MJPEG
640x480x30, not yet shipping. The other was from AITech. It does no compression
(better have a FAST disk array). Full studio quality video (even compressed)
overloads an ISA bus. Raw video is about 32 MB/sec. If you go 4x compression
(they say you can't do more without degrading quality slightly), it's still 8
MB/sec, too fast for ISA. Another BIGGER issue is the cpu ovehead of capturing.
If compressed to only 2/MB sec, that's still consumes a LARGE part of your cpu.
The ISA bus runs about 5.3 MB/sec, so that 2 MB/sec will probably consume about
40% of your processor, under perfect conditions. A PCI bus could deliver much
higher data rates with much lower cpu use. The cpu is then free to do the
appropriate houskeeping (initiating disk i/o, updating the preview window,
recording the sound, keeping the user interface responsive). – Jan