Subject: Re: [linux-audio-dev] Laaga multiple sample rates (Re: LAAGA: updates, laaga-0.2.0 tarball available)
From: Steve Harris (S.W.Harris_AT_ecs.soton.ac.uk)
Date: Mon Jul 09 2001 - 16:47:09 EEST
On Mon, Jul 09, 2001 at 03:31:29PM +0300, Jarno Seppanen wrote:
> Hi Paul, others,
>
> having skimmed through the source, at least one thing that should be added
> came into my mind: support for per-port sample rates. I'll start with
> motivation: it is not so far from reality to have to work with many sample
> rates with a Linux box, for example when dealing with a 96 kHz recording
> project, a CD player and a DAT recorder at the same time. Now, if Laaga
> intends to be a layer for interoperation and integration of all Linux music
> apps, I sure bet it has to be able to connect (say) a 48 kHz DAT stream to
> (say) a 96 kHz Ardour input.
I don't think this is a good idea myself:
1) there are dozens of up/downsampling techniques with different
tradeoffs, so picking the right one automatically is not really
possible (unlike mixing).
2) its too complicated
3) its too complicated
In your example I think you should really run the system at 96k, and the
input driver for the DAT/CD player should do the upsampling to 96k.
or
have two LAAGA systems running concurrently with a sample rate converting
bridge between them. The bridge is going to be a scary piece of code
though, and it would have to introduce extra latency.
I agree with you about the use of the term frame though. It is confusing,
especially if you have to talk about SMPTE in the same sentance. However,
sample is not neccearily correct either.
- Steve
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