[MPlayer-users] Significant CPU utilization with >2 channels?

[Eric Brundick]

I've recently begun using MPlayer as my MP3 player because it's the only
program I know of thus far which allows me to shift channels from FL/FR
to others.

In my setup, I have an SB Audigy2 ZS with headphones hooked up to the
main channels (FL/FR) and a stereo system hooked up to the rear channels
(RL/RR).  I use the headphones for Skype, while I play music and movies
on the rear channels.  (thus I'm not using it for true "surround", just
using the rear channels like a second soundcard)

I use the following command to play mp3s:
alias mp3='mplayer -channels 4 -ac mad -af equalizer=1:2:1:0:0:0:0:1:2:4,channels=4:2:0:2:1:3,volume=30:-1'

Problem is, this ends up using around 60-90% CPU on an AMD Athlon64
3000+.

If I subtract "-channels 4" and the channels= piece of -af, it uses more
like 0.1% CPU, and plays out of the headphones.  Note that this behavior
persists whether I'm using Skype in parallel or not, so I am fairly
certain Skype has nothing to do with it.

If I subtract "-channels 4" but keep the channels= piece in place, it
still only uses ~0.1-0.4% CPU, but I get no sound.

I noticed an older thread mentioning this: http://www1.mplayerhq.hu/pipermail/mplayer-users/2003-October/039180.html

For the record, this is my ~/.mplayer/config:
vo=xv
fs=1
ao=alsa
monitoraspect=16:10

System details:
MPlayer version 1.0pre7try2, tried the mp3lib and libmad audio codecs,
no apparent difference.

AMD Athlon64 3000+ running Ubuntu 5.10 Breezy Badger x86_64
(same problem happened with Ubuntu 5.10 i386/32-bit mode)
SB Audigy2 ZS soundcard (not the 'platinum' edition)
MP3s are being played over NFS.


Any help is appreciated
Thanks!