[Qemu-devel] [PATCH v2 1/6] qapi: qapi for audio backends

[Kővágó, Zoltán]

This patch adds structures into qapi to replace the existing configuration
structures used by audio backends currently. This qapi will be the base of the
-audiodev command line parameter (that replaces the old environment variables
based config).

This is not a 1:1 translation of the old options, I've tried to make them much
more consistent (e.g. almost every backend had an option to specify buffer size,
but the name was different for every backend, and some backends required usecs,
while some other required frames, samples or bytes). Also tried to reduce the
number of abbreviations used by the config keys.

Some of the more important changes:
* use `in` and `out` instead of `ADC` and `DAC`, as the former is more user
  friendly imho
* moved buffer settings into the global setting area (so it's the same for all
  backends that support it. Backends that can't change buffer size will simply
  ignore them). Also using usecs, as it's probably more user friendly than
  samples or bytes.
* try-poll is now an alsa and oss backend specific option (as all other backends
  currently ignore it)

Signed-off-by: Kővágó, Zoltán <address@hidden>

---

Changes from v1 patch:
* every time-related field now take usecs (and removed -usecs, -millis suffixes)
* fixed inconsisten optional marking, language issues

Changes from v2 RFC patch:
* in, out are no longer optional
* try-poll: moved to alsa and oss (as no other backend used them)
* voices: added (env variables had this option)
* dsound: removed primary buffer related fields

Changes from v1 RFC patch:
* fixed style issues
* moved definitions into a separate file
* documented undocumented options (hopefully)
* removed plive option. It was useless even years ago so it can probably safely
  go away: 
https://lists.nongnu.org/archive/html/qemu-devel/2012-03/msg02427.html
* removed verbose, debug options. Backends should use trace events instead.
* removed *_retries options from dsound. It's a kludge.
* moved buffer_usecs and buffer_count to the global config options. Some driver
  might ignore it (as they do not expose API to change them).
* wav backend: removed frequecy, format, channels as AudiodevPerDirectionOptions
  already have them.

Makefile         |   4 +-
 qapi-schema.json |   3 +
 qapi/audio.json  | 223 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 228 insertions(+), 2 deletions(-)
 create mode 100644 qapi/audio.json

diff --git a/Makefile b/Makefile
index 3f97904..ac566fa 100644
--- a/Makefile
+++ b/Makefile
@@ -257,8 +257,8 @@ $(SRC_PATH)/qga/qapi-schema.json 
$(SRC_PATH)/scripts/qapi-commands.py $(qapi-py)
                "  GEN   $@")
 
 qapi-modules = $(SRC_PATH)/qapi-schema.json $(SRC_PATH)/qapi/common.json \
-               $(SRC_PATH)/qapi/block.json $(SRC_PATH)/qapi/block-core.json \
-               $(SRC_PATH)/qapi/event.json
+               $(SRC_PATH)/qapi/audio.json  $(SRC_PATH)/qapi/block.json \
+               $(SRC_PATH)/qapi/block-core.json $(SRC_PATH)/qapi/event.json
 
 qapi-types.c qapi-types.h :\
 $(qapi-modules) $(SRC_PATH)/scripts/qapi-types.py $(qapi-py)
diff --git a/qapi-schema.json b/qapi-schema.json
index 106008c..e751ea3 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -5,6 +5,9 @@
 # QAPI common definitions
 { 'include': 'qapi/common.json' }
 
+# QAPI audio definitions
+{ 'include': 'qapi/audio.json' }
+
 # QAPI block definitions
 { 'include': 'qapi/block.json' }
 
diff --git a/qapi/audio.json b/qapi/audio.json
new file mode 100644
index 0000000..2851689
--- /dev/null
+++ b/qapi/audio.json
@@ -0,0 +1,223 @@
+# -*- mode: python -*-
+#
+# Copyright (C) 2015 Zoltán Kővágó <address@hidden>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or later.
+# See the COPYING file in the top-level directory.
+
+##
+# @AudiodevNoOptions
+#
+# The none, coreaudio, sdl and spice audio backend have no options.
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevNoOptions',
+  'data': { } }
+
+##
+# @AudiodevAlsaPerDirectionOptions
+#
+# Options of the alsa backend that are used for both playback and recording.
+#
+# @dev: #optional the name of the alsa device to use
+#
+# @try-poll: #optional attempt to use poll mode
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevAlsaPerDirectionOptions',
+  'data': {
+    '*dev':      'str',
+    '*try-poll': 'bool' } }
+
+##
+# @AudiodevAlsaOptions
+#
+# Options of the alsa audio backend.
+#
+# @in: options of the capture stream
+#
+# @out: options of the playback stream
+#
+# @threshold: #optional set the threshold (in frames) when playback starts
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevAlsaOptions',
+  'data': {
+    'in':         'AudiodevAlsaPerDirectionOptions',
+    'out':        'AudiodevAlsaPerDirectionOptions',
+    '*threshold': 'int' } }
+
+##
+# @AudiodevDsoundOptions
+#
+# Options of the dsound audio backend.
+#
+# @latency: #optional add extra latency to playback (in microseconds)
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevDsoundOptions',
+  'data': {
+    '*latency': 'int' } }
+
+##
+# @AudiodevOssPerDirectionOptions
+#
+# Options of the oss backend that are used for both playback and recording.
+#
+# @dev: #optional path of the oss device
+#
+# @try-poll: #optional attempt to use poll mode
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevOssPerDirectionOptions',
+  'data': {
+    '*dev':      'str',
+    '*try-poll': 'bool' } }
+
+##
+# @AudiodevOssOptions
+#
+# Options of the oss audio backend.
+#
+# @in: options of the capture stream
+#
+# @out: options of the playback stream
+#
+# @mmap: #optional try using memory mapped access
+#
+# @exclusive: #optional open device in exclusive mode (vmix won't work)
+#
+# @dsp-policy: #optional set the timing policy of the device, -1 to use 
fragment
+#              mode (option ignored on some platforms)
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevOssOptions',
+  'data': {
+    'in':          'AudiodevOssPerDirectionOptions',
+    'out':         'AudiodevOssPerDirectionOptions',
+    '*mmap':       'bool',
+    '*exclusive':  'bool',
+    '*dsp-policy': 'int' } }
+
+##
+# @AudiodevPaOptions
+#
+# Options of the pa (PulseAudio) audio backend.
+#
+# @server: #optional PulseAudio server address
+#
+# @sink: #optional sink device name
+#
+# @source: #optional source device name
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevPaOptions',
+  'data': {
+    '*server': 'str',
+    '*sink':   'str',
+    '*source': 'str' } }
+
+##
+# @AudiodevWavOptions
+#
+# Options of the wav audio backend.
+#
+# @path: #optional path of the wav file to record
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevWavOptions',
+  'data': {
+    '*path': 'str' } }
+
+
+##
+# @AudiodevBackendOptions
+#
+# A discriminated record of audio backends.
+#
+# Since: 2.4
+##
+{ 'union': 'AudiodevBackendOptions',
+  'data': {
+    'none':      'AudiodevNoOptions',
+    'alsa':      'AudiodevAlsaOptions',
+    'coreaudio': 'AudiodevNoOptions',
+    'dsound':    'AudiodevDsoundOptions',
+    'oss':       'AudiodevOssOptions',
+    'pa':        'AudiodevPaOptions',
+    'sdl':       'AudiodevNoOptions',
+    'spice':     'AudiodevNoOptions',
+    'wav':       'AudiodevWavOptions' } }
+
+##
+# @AudioFormat
+#
+# An enumeration of possible audio formats.
+#
+# Since: 2.4
+##
+{ 'enum': 'AudioFormat',
+  'data': [ 'u8', 's8', 'u16', 's16', 'u32', 's32' ] }
+
+##
+# @AudiodevPerDirectionOptions
+#
+# General audio backend options that are used for both playback and recording.
+#
+# @fixed-settings: #optional use fixed settings for host DAC/ADC
+#
+# @frequency: #optional frequency to use when using fixed settings
+#
+# @channels: #optional number of channels when using fixed settings
+#
+# @format: #optional sample format to use when using fixed settings
+#
+# @buffer: #optional the buffer size (in microseconds)
+#
+# @buffer-count: #optional number of buffers
+#
+# Since: 2.4
+##
+{ 'struct': 'AudiodevPerDirectionOptions',
+  'data': {
+    '*fixed-settings': 'bool',
+    '*frequency':      'int',
+    '*channels':       'int',
+    '*voices':         'int',
+    '*format':         'AudioFormat',
+    '*buffer':         'int',
+    '*buffer-count':   'int' } }
+
+##
+# @Audiodev
+#
+# Captures the configuration of an audio backend.
+#
+# @id: identifier of the backend
+#
+# @in: options of the capture stream
+#
+# @out: options of the playback stream
+#
+# @timer-period: #optional timer period (in microseconds, 0: use lowest
+#                possible)
+#
+# @opts: audio backend specific options
+#
+# Since: 2.4
+##
+{ 'struct': 'Audiodev',
+  'data': {
+    '*id':           'str',
+    'in':            'AudiodevPerDirectionOptions',
+    'out':           'AudiodevPerDirectionOptions',
+    '*timer-period': 'int',
+    'opts':          'AudiodevBackendOptions' } }
-- 
2.4.3