-[Which Audio Interface or Soundcard is compatible with Engine Core?](#which-audio-interface-or-soundcard-is-compatible-with-engine-core)
-[How can I find the audio device IDs, required for settings in engine-core.ini?](#how-can-i-find-the-audio-device-ids-required-for-settings-in-engine-coreini)
-[How to solve 'Error when starting output output_lineout_0: Failure("Error while setting open_pcm: Device or resource busy")!'?](#how-to-solve-error-when-starting-output-output_lineout_0-failureerror-while-setting-open_pcm-device-or-resource-busy)
-[How to avoid stutter, hangs, artifacts or in general glitchy sound?](#how-to-avoid-stutter-hangs-artifacts-or-in-general-glitchy-sound)
-[Read More](#read-more)
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## Which Audio Interface or Soundcard is compatible with Engine Core?
Basically any audio device which is supported by Linux Debian/Ubuntu and has ALSA, JACK or Pulse Audio support.
## How can I find the audio device IDs, required for settings in engine-core.ini?
**ALSA**: You can get the device numbers or IDs by executing `cat /proc/asound/cards`. Other helpful commands are `aplay -l`, `aplay -L` and `alsamixer`.
To test if you device is able to output audio try `speaker-test`. If you are running Engine Core using Docker, run the speaker test from within your docker container.
**Pulse Audio**: You might not need this for Pulse Audio as the `default` device might be sufficient. To choose a specific one its ID can be found using `pactl list`
**[clock.wallclock_alsa:2] Error when starting output lineout: Failure("Error while setting open_pcm: No such file or directory")!**
Assure you have set the correct device ID. To do so check the aformentioned question. Check the audio interface configuration section in `engine-core.ini`. Verify if the default settings `input_device_0` and `output_device_0` are valid device IDs.
In case your are *not* running Engine Core within Docker, also check if your executing user (è.g. `engineuser`) belongs to the group `audio`.
## How to solve 'Error when starting output output_lineout_0: Failure("Error while setting open_pcm: Device or resource busy")!'?
You probably have set a wrong or occupied device ID. The device could be reserved by another software using the ALSA sound system. Or you might be accessing a device using ALSA which is already assigned to the Pulse Audio sound system. Here it could help to [remove the device from PulseAudio](https://jamielinux.com/blog/tell-pulseaudio-to-ignore-a-usb-device-using-udev/) before accessing it.
## How to avoid stutter, hangs, artifacts or in general glitchy sound?
This can have various reasons, but first of all it's good to check the `engine-core.log` logs.
**Incorrect ALSA buffer settings**: If the ALSA settings provided by your system are not working cleanly the `engine-core.ini` settings provide to option to override parameters such as `alsa_buffer`. The correct settings are individual to the used soundcard but in general this is a tricky topic. In our case we had more success using PulseAudio or JACK instead. Recommendations are welcome.
**These problems occurr while having Icecast streaming enabled**: Try to reduce the quality of the stream, especially when you are experiencing hangs on the stream. Check your Icecast connection. Is it up and running? Maybe there is some authentication issue or an [Icecast limitation for max clients](ttps://github.com/savonet/liquidsoap/issues/524).
**The hardware is hitting its limits**: Also check the relevant logs and the system utilization. Are there other processes using up the machines resources? You might even be hitting the performance limit of your hardware. Maybe using a realtime linux kernel could help too.
