Re: bandwidth limits
Re: bandwidth limits
- Subject: Re: bandwidth limits
- From: "Roman Thilenius" <email@hidden>
- Date: Tue, 23 Sep 2003 18:12:46 +0200 (MEST)
>
Thanks for all the feedback on output capacity. What I am hearing is
>
that what I want to do is not at all pushing the limits of performance,
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and that's a good thing.
>
>
The only other issue is that if I am pushing 48 streams of audio out of
>
the computer, what is the most efficient path from HD to output?
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Should I use lossless data compression and unpack it in a processing
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thread to minimize disk I/O, should I use purely uncompressed files off
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a RAID array to minimize CPU time, and what format should I send to
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CoreAudio? I guess I have a choice of floats or linear-PCM. What will
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be faster/better for this saturation case?
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>
Thanks a lot for the input- this is incredibly helpful.
>
>
Austin Shoemaker
nice that you emptied your mailbox now, so that you finally could read
all our offtopic replies :)
you will not use any compression for realtime streaming of audio or video,
that would need a bit too much CPU.
if i understand you right youre building an app for custom use - but i dont
know
how that will look like.
>
most efficient path from HD to output?
preloading into memory, then sending to coreaudio.
last but not least, with a hardware IO which fully supports coreaudio
drivers.
but please dont dopreloading if you are making a sequencer, hehe. more for a
sampler or something like that where you can foresee filesize will be
limited.
>
and what format should I send to
>
CoreAudio? I guess I have a choice of floats or linear-PCM. What will
>
be faster/better for this saturation case?
float formats are only existing in 32bit (or higher) depth files.
i believe (and they will correct me here soon when that is wrong), that
there
is no way of saving CPU by sending lets say, 8bit format to coreaudio.
the only thing what makes immediately a difference is the samplingrate,
- which you will not make fixed, because that will always depend on the
hardware IO you use.
of course, reading from disk is affetced: 32 bit files are 2x longer than 16
bit files :)
in general, you dont make the file format decision up on hardwarespecs or
something, choose it on the quality you need.
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