[CentOS] Video Recording

Sun Nov 27 16:01:08 UTC 2005
Bryan J. Smith <thebs413 at earthlink.net>

On Sat, 2005-11-26 at 23:14 -0800, Ajay Sharma wrote:
> Oh, and the CPU usage is tiny so you can capture several streams with 
> multiple PVR-150 cards in a decent desktop box.

Just FYI, it's more than just CPU usage.  A "raw" analog NTSC video
stream (I'm assuming NTSC) is over 30MBps.  Considering it goes from
card to memory to disk -- possibly all over the same, shared 32-bit @
33MHz PCI bus (133MBps), it saturates much of the PCI bus, so frame loss
is probable.

So having at least an MJPEG compressed stream reduces that far more to a
measly 1-6MBps (depending on compression ratio), and MPEG-2 typically to
under 1MBps.  You usually want to capture MJPEG if you are going to edit
the video (especially if you need high quality, individual frames), or
MPEG-2 when you only might recorder/cut it or possibly convert it to a
lower-quality anyway.


-- 
Bryan J. Smith   mailto:b.j.smith at ieee.org
http://thebs413.blogspot.com
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