Choppy sound

Hi,

Is anyone else getting choppy sound on the latest (and the preview) versions? I get sound, but it's very distorted.

Using Debian/testing, sound driver is ALSA, CMI9880.

Any suggestions for where to look for problems?

Thanks

I get choppy sound with the ALSA driver as well, although it seems to work fine with the OSS driver (but that locks my sound device so nothing else can use it, which is a pain).

I'm using the 1.12.0.51742 client on Debian/unstable, x86_64.

Im getting choppy audio on Ubuntu Dapper with a Chaintech AV710 (AKA ICE1712/24 driver)/ALSA driver...
If you get any hints, let me know

I used to have choppy sound using alsa w/ the new client but resolved it by loading in the "alsa-oss" package and running the client thru aoss. ymmv.

This didn't work for me. Did you do anything special besides "aoss ./secondlife"?

I didn't have any luck with aoss either. For me it stopped the sound altogether.

OK, doing some digging on t'internet I've come up with the following:

I created a .asoundrc file in my home directory:

pcm.my_card {
        type hw
        card 0
        mmap_emulation true
}

pcm.dmixed {
        type dmix
        ipc_key 1024
#       ipc_key_add_uid false   # let multiple users share
#       ipc_perm 0666           # IPC permissions for multi user sharing (octal, default 0600)

        slave {
                pcm "my_card"
                rate 48000
#               period_size 512
        }

}

pcm.dsnooped {
        type dsnoop
        ipc_key 2048
        slave {
                pcm "my_card"
                rate 48000
                period_size 128
        }
}

pcm.asymed {
        type asym
        playback.pcm "dmixed"
        capture.pcm "dsnooped"
}

pcm.pasymed {
        type plug
        slave.pcm "asymed"
        }

pcm.dsp0 {
        type plug
        slave.pcm "asymed"
}

pcm.!default {
        type plug
        slave.pcm "asymed"
}

Then run Second Life use "aoss ./secondlife"

Seems to work for me, almost no choppiness now either on audio streams or in-world sounds. I don't know enough about ALSA to say how much of that config file is stricty necessary.

Also I still get these messages:

FSOUND_Output_OSS_Wait : Timeout on audio write.  Caused by bad driver!

And it still occasionally goes through a choppy spell, but not as bad as before.

Hope this is of some help.

Hi there.
If you're experiencing problems with choppy sound, you can try setting the LL_BAD_OSS environment variable before starting SL (or put it in the secondlife script). This will make SL avoid OSS audio by default.
This only works on the very latest (r52222) Linux client. Please report if this significantly helps.

Hi Tofu,

What are you supposed to set it to? I did export LL_BAD_OSS=1, started SL, didn't get any sound.

Hinkley

Anything...Okay. There are good reasons why we don't avoid OSS by default. But thanks for trying it.

Though using OSS on many integrated sound chips (AC97 etc) may cause SL to steal the card from all other apps wanting to access sound.

I've had a lot of success putting the aoss command directly into the secondlife script.

My current secondlife launcher script as of today's new release:

#!/bin/sh
nvidia-settings --load-config-only
cd `dirname $0`
LD_LIBRARY_PATH=lib aoss bin/secondlife-bin $@ 2>&1 | tee lastrun.log

That nvidia-settings line is to make sure that the application overrided settings I have for anti-aliasing and anisotropic filtering are enabled. SL graphics rendering is so CPU bound that there's essentially no performance hit for cranking those settings up and enjoying the non-jaggyness.

Yeah. That was the case with my setup and my wife's. Audacious didn't want to give any musical joy while SL was running. Tapping the power of alsa-oss through aoss saved the day.

EDIT: Come to think of it, before applying aoss, we had this problem with our non-integrated sound cards. (Hers a Turtle Beach Riviera, mine an M-Audio Delta 410)

Yep, it appears that SL tries OSS output first, then if that fails (it just about never does!) it will try ALSA, if that fails it will try ESD(esound - gnome). It should probably go the other way. OSS pretty much always takes over the sound card and doesn't share on any card that doesn't have mixing in hardware. Should perhaps try ESD/arts first, then ALSA, then OSS. Or be an option for the user. Many people don't have great cards, emu101k or such sound blaster cards will work nicely as they are hardware based though this isn't something people should be forced to go out and buy a piece of hardware for.

Thanks everyone, I now have perfect working sound...

Installing esd and enabling it in the Gnome sound menu did the trick, sounds great now.

Hinkley

ESD typically adds about half a second of audio lag. ALSA is good for many reasons but causes startup hangs on some systems when SL is the first process to access audio, which is why it's behind OSS by default.

I still get choppy streams with LL_BAD_OSS set. For that matter, all the sound is rather choppy...

Linux sound is very sensitive to hardware which is part of the problem. Using OSS on top of software based sound support may end up with some chop to it. Best to test the sound of your system through OSS, then see if SL itself performs differently than other OSS based applications. 64bit aoss wrapper does not appear to work at this time for those using full 64 bit distributions of Debian or Ubuntu.

Quick fix for this is to get a hardware based sound system such as a emu10k based card, they tend to be cheap now if you can find them.

This this sound card specific, but may help other laptop users experiencing choppy sound. I have a Dell Inspiron E1505 with a HDA Intel / SigmaTel STA9200 card; it uses the snd_hda_intel ALSA modules with OSS emulation.

edit /etc/modprobe.d/options
add: "options snd-hda-intel position_fix=1"
reboot