[Solved] ALI M5451 (CS4299) vmix is unusable

[Mr. Tao]

I have installed OSS 4.2 on an laptop and everything works fine except vmix. Every sound reproduced is accompanied by static noise when vmix is enabled. I've tried changing mixing rates with vmixctl but no luck.

• ossinfo -v3
• http://pastebin.com/df500156ossmix

[cesium]

Lets try this:

Edit /usr/lib/oss/conf/osscore.conf and add "vmix_no_autoattach=1" line. Then attach vmix manually using vmixctl command and '-M' switch. Does it work better?

[Mr. Tao]

I tried vmixctl attach -M /dev/oss/oss_trident0/pcm0 and pcm1 too. Static is still there when more than one program outputs audio. Moreover, when attached to pcm1 only one program could play as second instance of mplayer complained [AO OSS] audio_setup: Can't open audio device /dev/dsp: Device or resource busy and used SDL as fallback.

[cesium]

It isn't enough to just attach vmix to pcm1 to get mplayer to use it. You need to change /dev/dsp to point to it (see here), or use mplayer switch to mplayer use pcm1 ("-ao oss:/dev/oss/oss_trident0/pcm1").

If that doesn't work, lets try something else:
Run "sudo sed -i -e "s/memlimit < 0x00000000ffffffffLL/memlimit <= 0x00000000ffffffffLL/" /usr/lib/oss/build/osscore.c", "cd /usr/lib/oss/build", "sh install.sh", and then restart OSS with "sudo soundoff" and "sudo soundon".

[Mr. Tao]

It isn't enough to just attach vmix to pcm1 to get mplayer to use it. You need to change /dev/dsp to point to it (see here), or use mplayer switch to mplayer use pcm1 ("-ao oss:/dev/oss/oss_trident0/pcm1").

Sorry for late reply. I tested your recommendation right now and yes! it seems to be working . I let multiple instances of mplayer play through pcm1 and I didn't notice any static noise. For comparison I checked pcm0 again and it's still full of static.

Thank you very much! I'm going to change /dev/dsp symlink now.

Do I need to always attach like sudo vmixctl attach -M /dev/oss/oss_trident0/pcm1 or is there a way to make this change permanent?

[cesium]

You can add the line to /usr/lib/oss/soundon.user (before "exit 0" line). Then do "sudo chmod +x /usr/lib/oss/soundon.user", and that line will be executed every OSS startup (the wiki link described this). I'm not sure you need '-M' though - try attaching vmix without using it.

[Mr. Tao]

Awesome! Works fine without -M. Thank you very much!