[pvrusb2] In-kernel-2.6.18 video stutter & video size?

[Mike Isely]

On Sun, 15 Oct 2006, Julio Arruda wrote:

> Mike Isely wrote:
> > The pvrusb2 driver itself requires very little CPU to operate.  This is 
> > because all the heavy lifting is going on in the device's own mpeg2 
> > encoder hardware (which is after all the reason for this device in the 
> > first place).  The data stream coming from the device has bandwidth needs 
> > that are low enough that in many cases you can get away with running it 
> > under USB 1.1.  Worst case (with the bit rate maxed) the driver might have 
> > to push 3MB/sec, but more typically you're dealing with less than 1MB/sec.  
> > None of that should cause a CPU to saturate.
> 
> Humm...There is any cases where the pvrusb2 would have problems 
> "recording" the stream in USB1.1, and causing stutter in the recording ?
> 

Well of course.  If you set the hardware to use a sample bit rate that 
exceeds the USB 1.1 available bandwidth then it's probably going to have 
trouble...  Also keep in mind that if you have this device in any kind of 
topology where a USB 1.1 link is being shared with another device that 
there will be competition for the available bandwidth.

I've had at least one report that a single PVR USB2 device on a USB 1.1 
link with the default sample settings (6Mbps) works just fine.

  -Mike


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