Re: bandwidth limits
Re: bandwidth limits
- Subject: Re: bandwidth limits
- From: Austin Shoemaker <email@hidden>
- Date: Tue, 23 Sep 2003 20:16:29 -0700
Bill,
I have a few questions that I hope will guide my implementation in the
right direction:
1. Is AAC the best choice for optimal decode to a CoreAudio device with
48 outputs, or is there a better choice if disk space is unlimited?
2. How much QuickTime vs. CoreAudio should I use? I imagine I need
QuickTime to decode AAC files, but should I use QuickTime from
end-to-end or should I get the decompressed buffer from QuickTime and
route it through CoreAudio? If I need to do the latter, how do I get a
buffer from QuickTime instead of just having it play through?
Thanks a lot,
Austin
On Sep 23, 2003, at 3:15 PM, Bill Stewart wrote:
Roman, et al,
On Tuesday, September 23, 2003, at 09:12 AM, Roman Thilenius wrote:
you will not use any compression for realtime streaming of audio or
video,
that would need a bit too much CPU.
Not at all sure what you mean here.
QT's Broadcaster is able to broadcast using AAC (and other audio
codecs), speech based codecs like CELP, etc, also do not consume that
much CPU either and all of these are entirely usable in a real-time
situation. (For instance, AAC on an 800MHz iMac is somewhere in the
vicinity of 10% or "real" time for encoding. Decoding AAC on a similar
machine is now around 1-2% CPU usage).
You should do some research on the time these processes take as they
are in *very* common use (in fact far more use than doing NO
compression because the data rates are typically far more crucial and
limiting a factor than the CPU needed to compress the data within
real-time constraints) - this applies to video even more so than for
audio
Bill
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