Subject: Re: [linux-audio-dev] PCM Device Enumeration
From: Paul Davis (pbd_AT_op.net)
Date: Sat May 11 2002 - 03:13:19 EEST
>(radio broadcast automation and control). The goal there is to move audio
>data between the disk and the hardware in the most scalable manner possible,
>with little/no signal processing in the traditional sense being done on the
>data in transit.
What do you think is the goal of an HDR system while its recording or
playing back? Ardour can easily handle more tracks than my Ultra2
SCSI disks can support and thats on a measly PII-450...
> Since the data is already stored as FORMAT_S16_LE, and my
>target hardware will ultimately want the data in that same format, it's
>pointless as well as a waste of CPU cycles to convert to/from FORMAT_FLOAT_LE
>just for the sake of passing through Jack.
Have you actually measured the cost of doing this? I used to think
along the same lines as you are suggesting here. But then I noticed
that (1) all VST-hosting apps are forced to do the same thing,
including Nuendo, Cubase, Logic and others and (2) I measured how long
it takes.
Unless you are using a RAID, your disk subsystem can't possibly
provide enough data to make the sample format conversion into a real
issue on any modern machine. Yes, it obviously uses real cycles, but a
very small number of cycles, and I think that the benefits (uniform
sample format) far outweigh that cost. But YMMV.
--p
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