On 11 Mar 2007 13:13:20 -0700, "alfrodull@gmail.com"
<alfrodull@gmail.com> wrote:

>Hi,
>
>I'm looking for something that will run under windows or linux that
>measure exactly the data transfer speed of my external usb video
>capture box. I have a plextor m402u and I want to know exactly how
>many of them I can attach to one usb channel before the bandwidth is
>saturated. I also want to be able to benchmark what the transfer rate
>is at various resolutions, compressions, etc.

It's making MPEG2 streams, right? Just look at the bitrate
(per file, the MPEG2 settings used) of those and pad it by
about 10-15%. It would not be good to try to put multiple
on the same USB hub/port-pair, if you need more devices and
have ran out of hub pairs then add a PCI USB2 card or two.

>
>The tool I use would preferably be gpl'ed under linux, but I'll take a
>windows tool as long as it's some kind of free or free for personal/
>educational use. ;)
>
>Thanks,

A tool that tells you this still won't tell you want the
actual limit is on your specific ports using the data sizes
output by the capture device. It certainly won't be close
to USB's theoretical performance limit.