FS-UAE and external usb soundcard on Linux

[Speedvicio]

Frode a request.
I have a external usb soundcard not compatible with alsamixer but fully functional.
With this card fs-uae does not play any sound, probably because of incompatibility with alsamixer.
Can I choose from the emulator the audio output driver between pulseaudio,sdl or alsa?

[FrodeSolheim]

Originally Posted by Speedvicio

Frode a request.
I have a external usb soundcard not compatible with alsamixer but fully functional.
With this card fs-uae does not play any sound, probably because of incompatibility with alsamixer.
Can I choose from the emulator the audio output driver between pulseaudio,sdl or alsa?

Hi, I assume you mean that you get sound in at least some applications or with some drivers on Linux...

FS-UAE only uses OpenAL. But you most likely have the "soft openal" version which does not talk to the hardware directly, but through another audio driver/backend such as ALSA. OpenAL can have many different backends, and it is possible to choose which one is used.

Take a look at this:
http://repo.or.cz/w/openal-soft.git/...lsoftrc.sample

You are interested in this option:

## drivers:
#  Sets the backend driver list order, comma-seperated. Unknown backends and
#  duplicated names are ignored. Unlisted backends won't be considered for use
#  unless the list is ended with a comma (eg. 'oss,' will list OSS first
#  followed by all other available backends, while 'oss' will list OSS only).
#  Backends prepended with - won't be available for use (eg. '-oss,' will allow
#  all available backends except OSS). An empty list means the default.
drivers = pulse,alsa,core,oss,solaris,sndio,mmdevapi,dsound,winmm,port,opensl,null,wave

On my Ubuntu 12.04, OpenAL chooses PulseAudio output by default.
I tested it, creating ~/.alsoftrc with this content:

drivers = alsa

... and this forced OpenAL to use talk to ALSA directly on my system.

If you can use ALSA, and this USB device of yours is not the default device, you may need to consider this option as well (still in .alsoftrc -has nothing to do with FS-UAE !!):

[alsa]
## device:
#  Sets the device name for the default playback device.
#device = default

For a bit easier debugging, the next development release will output some helpful stuff to the log (example output for my computer):

fs_emu_audio_init
OpenAL devices:
- PulseAudio Default
- ALSA Default
- PortAudio Default
- No Output
openal default device: PulseAudio Default
openal device opened: PulseAudio Default

[Speedvicio]

Apparently it is the same problem I found with Mednafen.
Unfortunately, the only way to obtain the audio output would be to force the use of the sdl driver, which is not expected from the options of openal.

[FrodeSolheim]

Originally Posted by Speedvicio

Apparently it is the same problem I found with Mednafen.
Unfortunately, the only way to obtain the audio output would be to force the use of the sdl driver, which is not expected from the options of openal.

SDL does not talk to audio hardware directly either, like OpenAL, it too has support for different audio backends, like ALSA and PulseAudio. So the big question is, what does SDL do on your system that makes audio work for you?

If there were an SDL backend for OpenAL, you would basically have this:

FS-UAE -> OpenAL -> SDL -> ? -> USB soundcard

Unless SDL supports a backend which OpenAL does not, the following audio path should be able to work just as well:

FS-UAE -> OpenAL -> ? -> USB soundcard

* Have you tried fiddling with .alsoftrc?
* Do you know what audio backend / settings SDL uses on your system?

Once FS-UAE 1.3.0 is released, we'll be able to see in the log what audio system OpenAL chooses on your system, and what other options are available. It will then also be possible to see (in the log) that the audio backend options in .alsoftrc are properly applied.

[FrodeSolheim]

Here is a pre-release (1.3.0test1) to help you debug the audio problem:
http://fengestad.no/fs-uae/files/fs-....0test1.tar.gz

You can see in the changelog what audio backends are available on your system, and after making modifications to .alsoftrc, you can verify in the log file that the specified backend is actually used.