Uncanny CPU usage on non-compressed formats
Uncanny CPU usage on non-compressed formats
- Subject: Uncanny CPU usage on non-compressed formats
- From: Jose Commins <email@hidden>
- Date: Tue, 25 Mar 2003 13:21:15 +0000
Hi,
I've just played a sample (sic) 16-bit 44.1Khz AIFF through Quicktime
Player + internal audio hardware and registered an average of 12% CPU
usage on my 350Mhz B&W G3 - this seems an awful lot to me, considering
my Mac's internal audio is indeed 16-bit 44.1Khz, and playing Cinepak
movies consumes just about the same CPU time. What is going on to
register this CPU usage in Quicktime, considering playing this kind of
audio format should take 1% or less?
I also noticed when playing an audio CD through iTunes that again the
same CPU usage; what I suspect is that the incoming audio is being
converted to 32-bit float, band-split (for audio/visual effects, even
though they are switched off), then converted to the native audio
hardware, which is, well frankly, a waste of CPU cycles if the
frequency information isn't needed.
I've been hearing back from musicians sticking to OS9 despite the
increased latency - they see better audio performance accross similar
apps, including myself.
Regards,
Jose Commins.
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