qemu-e2k/qapi/audio.json
Martin Schrodt f614277765 audio/paaudio: prolong and make latency configurable
The latency of a connection to the PulseAudio server is determined by
the tlength parameter. This was hardcoded to 10ms, which is a bit too
tight on my machine, causing audio on host and guest to malfunction.
A setting of 15ms works fine here. To allow tweaking, I also made the
setting configurable via the new -audiodev config. This allows to squeeze out better timings in scenarios where the emulation allows it.

I also removed setting of the minreq parameter to (seemingly arbitrary) half the latency, since it showed worse audio quality during my tests. Allowing PulseAudio to request smaller chunks helped.

Signed-off-by: Martin Schrodt <martin@schrodt.org>
Message-id: 20190315084653.120020-3-martin@schrodt.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2019-03-18 12:21:15 +01:00

309 lines
7.2 KiB
Python

# -*- mode: python -*-
#
# Copyright (C) 2015-2019 Zoltán Kővágó <DirtY.iCE.hu@gmail.com>
#
# This work is licensed under the terms of the GNU GPL, version 2 or later.
# See the COPYING file in the top-level directory.
##
# @AudiodevPerDirectionOptions:
#
# General audio backend options that are used for both playback and
# recording.
#
# @fixed-settings: use fixed settings for host input/output. When off,
# frequency, channels and format must not be
# specified (default true)
#
# @frequency: frequency to use when using fixed settings
# (default 44100)
#
# @channels: number of channels when using fixed settings (default 2)
#
# @voices: number of voices to use (default 1)
#
# @format: sample format to use when using fixed settings
# (default s16)
#
# @buffer-length: the buffer length in microseconds
#
# Since: 4.0
##
{ 'struct': 'AudiodevPerDirectionOptions',
'data': {
'*fixed-settings': 'bool',
'*frequency': 'uint32',
'*channels': 'uint32',
'*voices': 'uint32',
'*format': 'AudioFormat',
'*buffer-length': 'uint32' } }
##
# @AudiodevGenericOptions:
#
# Generic driver-specific options.
#
# @in: options of the capture stream
#
# @out: options of the playback stream
#
# Since: 4.0
##
{ 'struct': 'AudiodevGenericOptions',
'data': {
'*in': 'AudiodevPerDirectionOptions',
'*out': 'AudiodevPerDirectionOptions' } }
##
# @AudiodevAlsaPerDirectionOptions:
#
# Options of the ALSA backend that are used for both playback and
# recording.
#
# @dev: the name of the ALSA device to use (default 'default')
#
# @period-length: the period length in microseconds
#
# @try-poll: attempt to use poll mode, falling back to non-polling
# access on failure (default true)
#
# Since: 4.0
##
{ 'struct': 'AudiodevAlsaPerDirectionOptions',
'base': 'AudiodevPerDirectionOptions',
'data': {
'*dev': 'str',
'*period-length': 'uint32',
'*try-poll': 'bool' } }
##
# @AudiodevAlsaOptions:
#
# Options of the ALSA audio backend.
#
# @in: options of the capture stream
#
# @out: options of the playback stream
#
# @threshold: set the threshold (in microseconds) when playback starts
#
# Since: 4.0
##
{ 'struct': 'AudiodevAlsaOptions',
'data': {
'*in': 'AudiodevAlsaPerDirectionOptions',
'*out': 'AudiodevAlsaPerDirectionOptions',
'*threshold': 'uint32' } }
##
# @AudiodevCoreaudioPerDirectionOptions:
#
# Options of the Core Audio backend that are used for both playback and
# recording.
#
# @buffer-count: number of buffers
#
# Since: 4.0
##
{ 'struct': 'AudiodevCoreaudioPerDirectionOptions',
'base': 'AudiodevPerDirectionOptions',
'data': {
'*buffer-count': 'uint32' } }
##
# @AudiodevCoreaudioOptions:
#
# Options of the coreaudio audio backend.
#
# @in: options of the capture stream
#
# @out: options of the playback stream
#
# Since: 4.0
##
{ 'struct': 'AudiodevCoreaudioOptions',
'data': {
'*in': 'AudiodevCoreaudioPerDirectionOptions',
'*out': 'AudiodevCoreaudioPerDirectionOptions' } }
##
# @AudiodevDsoundOptions:
#
# Options of the DirectSound audio backend.
#
# @in: options of the capture stream
#
# @out: options of the playback stream
#
# @latency: add extra latency to playback in microseconds
# (default 10000)
#
# Since: 4.0
##
{ 'struct': 'AudiodevDsoundOptions',
'data': {
'*in': 'AudiodevPerDirectionOptions',
'*out': 'AudiodevPerDirectionOptions',
'*latency': 'uint32' } }
##
# @AudiodevOssPerDirectionOptions:
#
# Options of the OSS backend that are used for both playback and
# recording.
#
# @dev: file name of the OSS device (default '/dev/dsp')
#
# @buffer-count: number of buffers
#
# @try-poll: attempt to use poll mode, falling back to non-polling
# access on failure (default true)
#
# Since: 4.0
##
{ 'struct': 'AudiodevOssPerDirectionOptions',
'base': 'AudiodevPerDirectionOptions',
'data': {
'*dev': 'str',
'*buffer-count': 'uint32',
'*try-poll': 'bool' } }
##
# @AudiodevOssOptions:
#
# Options of the OSS audio backend.
#
# @in: options of the capture stream
#
# @out: options of the playback stream
#
# @try-mmap: try using memory-mapped access, falling back to
# non-memory-mapped access on failure (default true)
#
# @exclusive: open device in exclusive mode (vmix won't work)
# (default false)
#
# @dsp-policy: set the timing policy of the device (between 0 and 10,
# where smaller number means smaller latency but higher
# CPU usage) or -1 to use fragment mode (option ignored
# on some platforms) (default 5)
#
# Since: 4.0
##
{ 'struct': 'AudiodevOssOptions',
'data': {
'*in': 'AudiodevOssPerDirectionOptions',
'*out': 'AudiodevOssPerDirectionOptions',
'*try-mmap': 'bool',
'*exclusive': 'bool',
'*dsp-policy': 'uint32' } }
##
# @AudiodevPaPerDirectionOptions:
#
# Options of the Pulseaudio backend that are used for both playback and
# recording.
#
# @name: name of the sink/source to use
#
# @latency: latency you want PulseAudio to achieve in microseconds
# (default 15000)
#
# Since: 4.0
##
{ 'struct': 'AudiodevPaPerDirectionOptions',
'base': 'AudiodevPerDirectionOptions',
'data': {
'*name': 'str',
'*latency': 'uint32' } }
##
# @AudiodevPaOptions:
#
# Options of the PulseAudio audio backend.
#
# @in: options of the capture stream
#
# @out: options of the playback stream
#
# @server: PulseAudio server address (default: let PulseAudio choose)
#
# Since: 4.0
##
{ 'struct': 'AudiodevPaOptions',
'data': {
'*in': 'AudiodevPaPerDirectionOptions',
'*out': 'AudiodevPaPerDirectionOptions',
'*server': 'str' } }
##
# @AudiodevWavOptions:
#
# Options of the wav audio backend.
#
# @in: options of the capture stream
#
# @out: options of the playback stream
#
# @path: name of the wav file to record (default 'qemu.wav')
#
# Since: 4.0
##
{ 'struct': 'AudiodevWavOptions',
'data': {
'*in': 'AudiodevPerDirectionOptions',
'*out': 'AudiodevPerDirectionOptions',
'*path': 'str' } }
##
# @AudioFormat:
#
# An enumeration of possible audio formats.
#
# Since: 4.0
##
{ 'enum': 'AudioFormat',
'data': [ 'u8', 's8', 'u16', 's16', 'u32', 's32' ] }
##
# @AudiodevDriver:
#
# An enumeration of possible audio backend drivers.
#
# Since: 4.0
##
{ 'enum': 'AudiodevDriver',
'data': [ 'none', 'alsa', 'coreaudio', 'dsound', 'oss', 'pa', 'sdl',
'spice', 'wav' ] }
##
# @Audiodev:
#
# Options of an audio backend.
#
# @id: identifier of the backend
#
# @driver: the backend driver to use
#
# @timer-period: timer period (in microseconds, 0: use lowest possible)
#
# Since: 4.0
##
{ 'union': 'Audiodev',
'base': {
'id': 'str',
'driver': 'AudiodevDriver',
'*timer-period': 'uint32' },
'discriminator': 'driver',
'data': {
'none': 'AudiodevGenericOptions',
'alsa': 'AudiodevAlsaOptions',
'coreaudio': 'AudiodevCoreaudioOptions',
'dsound': 'AudiodevDsoundOptions',
'oss': 'AudiodevOssOptions',
'pa': 'AudiodevPaOptions',
'sdl': 'AudiodevGenericOptions',
'spice': 'AudiodevGenericOptions',
'wav': 'AudiodevWavOptions' } }