1virtio sound 2============ 3 4This document explains the setup and usage of the Virtio sound device. 5The Virtio sound device is a paravirtualized sound card device. 6 7Linux kernel support 8-------------------- 9 10Virtio sound requires a guest Linux kernel built with the 11``CONFIG_SND_VIRTIO`` option. 12 13Description 14----------- 15 16Virtio sound implements capture and playback from inside a guest using the 17configured audio backend of the host machine. 18 19Device properties 20----------------- 21 22The Virtio sound device can be configured with the following properties: 23 24 * ``jacks`` number of physical jacks (Unimplemented). 25 * ``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. 26 * ``chmaps`` number of channel maps (Unimplemented). 27 28All streams are stereo and have the default channel positions ``Front left, right``. 29 30Examples 31-------- 32 33Add an audio device and an audio backend at once with ``-audio`` and ``model=virtio``: 34 35 * pulseaudio: ``-audio driver=pa,model=virtio`` 36 or ``-audio driver=pa,model=virtio,server=/run/user/1000/pulse/native`` 37 * sdl: ``-audio driver=sdl,model=virtio`` 38 * coreaudio: ``-audio driver=coreaudio,model=virtio`` 39 40etc. 41 42To specifically add virtualized sound devices, you have to specify a PCI device 43and an audio backend listed with ``-audio driver=help`` that works on your host 44machine, e.g.: 45 46:: 47 48 -device virtio-sound-pci,audiodev=my_audiodev \ 49 -audiodev alsa,id=my_audiodev 50