Subject: [linux-audio-dev] Re: [Alsa-devel] Fwd: Re: USB Quattro Linux support
From: Roger E Critchlow Jr (rec_AT_elf.org)
Date: Thu Apr 18 2002 - 05:25:48 EEST
Patrick Shirkey writes:
> --- Paul Davis <pbd_AT_op.net> wrote:
> >Not at all. arecord(1) can capture audio, but it can't capture 26
> >channels of audio at 64 frames/interrupt. Handling latency is partly
> >an application issue, partly a kernel issue, and partly a requirement
> >that libraries in the way don't get in the way. It has very little to
> >do with whether you can do certain generic tasks or not.
> >
>
> Sure. But usb audio devices are limited to a pretty low channel count.
>
> eg. this usb quattro can only capture 1 channel at 96000,24 bit
> even though it has up to 4 channels. It would seem to be a limitaion
> of usb as a transfer protocol.
>
USB-1.1 devices are limited, but USB-2.0 controllers are already on
the market and will be replacing USB-1.1 on new motherboards as the
year progresses. There's a 40 fold increase in raw bandwidth in
USB-2.0, from 12Mbit/s to 480Mbit/s, so one could imagine plugging
several CD-quality USB-1.1 audio devices into a USB-2.0 hub, or
getting multiple channels of DVD quality from a USB-2.0 audio
interface.
So, sooner or later, your driver,too, will get its chance to be a
latency bottleneck.
-- rec --
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