Subject: [linux-audio-dev] Re: Cached Audio Patent
From: Juhana Sadeharju (kouhia_AT_nic.funet.fi)
Date: ma helmi 28 2000 - 13:07:29 EST
>From: "Richard W.E. Furse" <richard_AT_muse.demon.co.uk>
>
>Computer Music Journal Vol 15 Number 3 Fall 1991
>Machine Tongues XIII: Real-Time Audio Conversion Under A Time-Sharing
>Operating System
>p35, within "The DSC Approach" to playing back audio files:
>
>"... The buffer contains no actual data when it is written. Instead, it is
>divided into two single-track buffers by the driver, and a different buffer
>header is associated with each half of the buffer. Each buffer is set up
>for DMA with calls to ubasetup() and is primed with sound data from disk
>before audio playback begins..."
Hmm.. I don't know. It could be just a audiofile player without
a wait for a key press.
I think the key press is important. If user selects N audiofiles from
directories, the beginnings of all of them should be preloaded, and
then program should wait for a key press. A friend here wrote this kind
of application at early '90 and installed the system to two public halls
(ice halls?).
I yet don't know what kind of DSP library he used but its manual
and library routines could have something to say on preloading.
-*-
Another feature could be equally important: the beginnings should stay
in the memory even the audiofile is playing --- somebody might retrigger
the same audiofile. This we could circumvent by keeping the same file
multiple times in memory (but wastes memory).
-*-
I got a hint that some games kept the first part of audiofile in memory
as a separate audiofile. So we could split audiofiles and use sequencer
for combining the audiofile at playtime. My realtime synth at 1995
did play samples and sequences upon key presses, so, that should not
be a problem.
-*-
Some random hints:
I checked Amiga manuals but I don't have access to Amiga 3000 manuals
which had a hard drive by default. Anyone?
Sound Forge manual tells something about preloading, details anyone?
Got a hint about Sound Designer II, anyone?
Fairlight, anyone? Their webpage only reveals that playing happen
instantly or such.
I looked at Lucasfilm system papers and there was only cue list stuff.
Nothing about that the playing starts immediately because audio data
is kept memory (if they are even kept).
Synclavier manuals did reveal nothing.
I looked also at radio jingle players without success.
-*-
I think we should forget this and just do what we want.
Yours,
Juhana
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