Thread: qemu sound
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Old 7th May 2009
BSDfan666 BSDfan666 is offline
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Hi Oko,

QEMU_OSS_DAC_DEV and QEMU_OSS_ADC_DEV just happen to be /dev/dsp by default.. a common Linuxism.

Code:
$ qemu -audio-help
Audio options:
  QEMU_AUDIO_DAC_FIXED_SETTINGS: boolean, default = 1
    Use fixed settings for host DAC
  QEMU_AUDIO_DAC_FIXED_FREQ: integer, default = 44100
    Frequency for fixed host DAC
  QEMU_AUDIO_DAC_FIXED_FMT: format, default = S16, (one of: U8 S8 U16 S16)
    Format for fixed host DAC
  QEMU_AUDIO_DAC_FIXED_CHANNELS: integer, default = 2
    Number of channels for fixed DAC (1 - mono, 2 - stereo)
  QEMU_AUDIO_DAC_VOICES: integer, default = 1
    Number of voices for DAC
  QEMU_AUDIO_ADC_FIXED_SETTINGS: boolean, default = 1
    Use fixed settings for host ADC
  QEMU_AUDIO_ADC_FIXED_FREQ: integer, default = 44100
    Frequency for fixed host ADC
  QEMU_AUDIO_ADC_FIXED_FMT: format, default = S16, (one of: U8 S8 U16 S16)
    Format for fixed host ADC
  QEMU_AUDIO_ADC_FIXED_CHANNELS: integer, default = 2
    Number of channels for fixed ADC (1 - mono, 2 - stereo)
  QEMU_AUDIO_ADC_VOICES: integer, default = 1
    Number of voices for ADC
  QEMU_AUDIO_TIMER_PERIOD: integer, default = 0
    Timer period in HZ (0 - use lowest possible)
  QEMU_AUDIO_PLIVE: boolean, default = 0
    (undocumented)
  QEMU_AUDIO_LOG_TO_MONITOR: boolean, default = 0
    print logging messages to montior instead of stderr

Available drivers:
Name: oss
Description: OSS http://www.opensound.com
Theoretically supports many playback voices
Theoretically supports many capture voices
Options:
  QEMU_OSS_FRAGSIZE: integer, default = 4096
    Fragment size in bytes
  QEMU_OSS_NFRAGS: integer, default = 4
    Number of fragments
  QEMU_OSS_MMAP: boolean, default = 0
    Try using memory mapped access
  QEMU_OSS_DAC_DEV: string, default = /dev/dsp
    Path to DAC device
  QEMU_OSS_ADC_DEV: string, default = /dev/dsp
    Path to ADC device
  QEMU_OSS_DEBUG: boolean, default = 0
    Turn on some debugging messages

Name: sdl
Description: SDL http://www.libsdl.org
One playback voice
Does not support capture
Options:
  QEMU_SDL_SAMPLES: integer, default = 1024
    Size of SDL buffer in samples

Name: none
Description: Timer based audio emulation
Theoretically supports many playback voices
Theoretically supports many capture voices
No options

Name: wav
Description: WAV renderer http://wikipedia.org/wiki/WAV
One playback voice
Does not support capture
Options:
  QEMU_WAV_FREQUENCY: integer, default = 44100
    Frequency
  QEMU_WAV_FORMAT: format, default = S16, (one of: U8 S8 U16 S16)
    Format
  QEMU_WAV_DAC_FIXED_CHANNELS: integer, default = 2
    Number of channels (1 - mono, 2 - stereo)
  QEMU_WAV_PATH: string, default = qemu.wav
    Path to wave file

Options are settable through environment variables.
Example:
  export QEMU_AUDIO_DRV=wav
  export QEMU_WAV_PATH=$HOME/tune.wav
(for csh replace export with setenv in the above)
  qemu ...
So you can either export QEMU_AUDIO_DRV=sdl or export QEMU_OSS_{ADC,DAC}_DEV=/dev/audio.

Hope that helps.
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