imdct36 CPU usage increase

Derk-Jan Hartman <[email protected]> Sat, 14 Feb 2004 16:30:35 +0100

Newsgroups	gmane.comp.audio.mad.devel
Message-ID	<[email protected]>

For some strange reason our latest version of VLC OSX more than doubles 
the CPU usage of mad_frame_decode, specifically the imdct36 routine it 
would seem. It is an OS X problem only and very annoying. Decoding mp3 
now requires 28% CPU usage on my G4/400 (used to be 12%).

libmad library version changes have been ruled out as the cause of 
this. Our mp3 decoder module didn't change either, but the demux module 
did change. We suspect it might be something like an alignment issue, 
but we can't seem to track it down..

Could you give some advice as to what might be the cause of this sudden 
increase in CPU usage, and how me may check some of our input for 
correctness?


DJ

---
Universiteit Twente
Derk-Jan Hartman (d.hartman at student.utwente dot nl)
http://home.student.utwente.nl/d.hartman