aze2cool
Tue Apr 17 22:52:02 CDT 2007
"DJSisolak" wrote:
> On Apr 17, 4:53 am, "Jerodequin" <jerodeq...@NOSPAMPLEASEhotmail.com>
> wrote:
> > "aze2cool" <aze2c...@discussions.microsoft.com> wrote in message
> >
> > news:B56D6888-55C4-4C24-AC91-625CCA9214BC@microsoft.com...
> >
> >
> >
> >
> >
> > >> "Tim Roberts" wrote:
> >
> > >> > In XP, USBAUDIO.SYS submits 10 packets of 400 bytes, and the device
> > >> > fills
> > >> > in however much arrives in each millisecond. So, the amount of data
> > >> > returned in each packet will vary based on the frequency, but those 10
> > >> > packets will always be 10 milliseconds.
> >
> > >> > What problem are you seeing?
> >
> > >> As you said in XP there are 10 packets whereas 4 packets in Vista. Is
> > >> that
> > >> what you expected to see under same hardware configurations?
> >
> > > Sorry.. what was I saying on last post!
> >
> > > I was trying to say that as you said that in XP there are always 10
> > > packets
> > > in every 10ms interval. However, I found that in Vista there are always 4
> > > packets instead of 10 (under same hardwares) and I just wondering whether
> > > Microsoft has changed it this way or purely my mistake.
> >
> > > aze2cool
> >
> > Could this be part of the reason so many with USB audio devices have found
> > they do not work under windows vista? (Devices are seen and recognised but
> > fail with a code 10 error). Many people have been switching the USBAudio.sys
> > that comes with Vista for a copy from XP without any ill effects which fixes
> > the issue until MS do.- Hide quoted text -
> >
> > - Show quoted text -
>
> The difference in the number of packets requested for capture does not
> have anything to do with device compatibility. The majority of the
> device failures from XP to Vista have come from a tightening of the
> driver to the specification. Usually this manifests due to a
> descriptor that is not class compliant. XP was not as strict and many
> bugs resulted which are fixed in the Vista version. If you are having
> a problem with a particular piece of hardware let me know and I will
> see if I can determine why it fails with the new driver.
>
> It is true that the number of packes submitted per request has changed
> from XP to Vista from 10 to 4. This was done to lower the latency for
> USBAudio capture.
>
> DJ Sisolak
> Microsoft Corp.
> (USB Audio driver developer)
>
Many thanks for your reply.
I am just curious that whether it is possible to switch back the number of
packet to "10" for some reason?
aze2cool