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Diffstat (limited to 'docs/system/devices/virtio-snd.rst')
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diff --git a/docs/system/devices/virtio-snd.rst b/docs/system/devices/virtio-snd.rst new file mode 100644 index 0000000..2a9187f --- /dev/null +++ b/docs/system/devices/virtio-snd.rst @@ -0,0 +1,49 @@ +virtio sound +============ + +This document explains the setup and usage of the Virtio sound device. +The Virtio sound device is a paravirtualized sound card device. + +Linux kernel support +-------------------- + +Virtio sound requires a guest Linux kernel built with the +``CONFIG_SND_VIRTIO`` option. + +Description +----------- + +Virtio sound implements capture and playback from inside a guest using the +configured audio backend of the host machine. + +Device properties +----------------- + +The Virtio sound device can be configured with the following properties: + + * ``jacks`` number of physical jacks (Unimplemented). + * ``streams`` number of PCM streams. At the moment, no stream configuration is supported: the first one will always be a playback stream, an optional second will always be a capture stream. Adding more will cycle stream directions from playback to capture. + * ``chmaps`` number of channel maps (Unimplemented). + +All streams are stereo and have the default channel positions ``Front left, right``. + +Examples +-------- + +Add an audio device and an audio backend at once with ``-audio`` and ``model=virtio``: + + * pulseaudio: ``-audio driver=pa,model=virtio`` + or ``-audio driver=pa,model=virtio,server=/run/user/1000/pulse/native`` + * sdl: ``-audio driver=sdl,model=virtio`` + * coreaudio: ``-audio driver=coreaudio,model=virtio`` + +etc. + +To specifically add virtualized sound devices, you have to specify a PCI device +and an audio backend listed with ``-audio driver=help`` that works on your host +machine, e.g.: + +:: + + -device virtio-sound-pci,audiodev=my_audiodev \ + -audiodev alsa,id=my_audiodev |