Re: which pci sound card does not have dropouts under load
Brian Gerst (bgerst@quark.vpplus.com)
Wed, 03 Mar 1999 16:52:21 -0500
Alan Cox wrote:
>
> > > > What about CD audio or MIDI? Do you have to rip the CD in realtime to
> > > > play it? [Of course you could just rip it anyways and convert to mp3].
> > >
> > > You rip it ahead of real time and queue it in memory, the controller clocks it
> > > out for you. And yes its done ripping - Digital all the way
> >
> > And so they've just invented another 'Win' device. Offload as much to
> > the CPU as you can... *sigh*
>
> Let me see. You DMA a block into memory, the USB controller DMA's it out
> on hard timed interval. The CPU doesnt touch the data for even a lowish end
> USB set up. When you've heard PC audio with no hiss, when you turn the speakers
> right up and you can't hear the CPU I think you'll like it too
Reading digital audio from a CD is more involved than just telling the
IDE/SCSI controller to DMA it in. You have to do the ECC error
correction, jitter correction, etc. that the drive would have normally
done, if you want scratch and pop free audio.
I'll shut up now since this is getting off topic.
--
Brian Gerst
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