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[Qemu-devel] [PATCH 22/25] audio: add mixeng option (documentation)
From: |
Kővágó, Zoltán |
Subject: |
[Qemu-devel] [PATCH 22/25] audio: add mixeng option (documentation) |
Date: |
Thu, 6 Aug 2015 20:28:34 +0200 |
This will allow us to disable mixeng when we use a decent backend.
Disabling mixeng have a few advantages:
* we no longer convert the audio output from one format to another, when
the underlying audio system would just convert it to a third format.
We no longer convert, only the underlying system, when needed.
* the underlying system probably has better resampling and sample format
converting methods anyway...
* we may support formats that the mixeng currently does not support (S24
or float samples, more than two channels)
* when using an audio server (like pulseaudio) different sound card
outputs will show up as separate streams, even if we use only one
backend
Disadvantages:
* audio capturing no longer works (wavcapture, and vnc audio extension)
* some backends only support a single playback stream or very picky
about the audio format. In this case we can't disable mixeng.
However mixeng is not removed, only made optional, so this shouldn't be
a big concern.
Signed-off-by: Kővágó, Zoltán <address@hidden>
---
qapi/audio.json | 5 +++++
qemu-options.hx | 6 ++++++
2 files changed, 11 insertions(+)
diff --git a/qapi/audio.json b/qapi/audio.json
index b57b215..0216a10 100644
--- a/qapi/audio.json
+++ b/qapi/audio.json
@@ -184,6 +184,10 @@
#
# General audio backend options that are used for both playback and recording.
#
+# @mixeng: #optional use QEMU's mixing engine to mix all streams inside QEMU.
+# When set to off, fixed-settings must be also off. Not every backend
+# compatible with the off setting (default on)
+#
# @fixed-settings: #optional use fixed settings for host input/output. When
# off, frequency, channels and format must not be specified
# (default on)
@@ -207,6 +211,7 @@
##
{ 'struct': 'AudiodevPerDirectionOptions',
'data': {
+ '*mixeng': 'bool',
'*fixed-settings': 'bool',
'*frequency': 'int',
'*channels': 'int',
diff --git a/qemu-options.hx b/qemu-options.hx
index 60a3563..bd922bf 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -329,6 +329,7 @@ DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
" specifies the audio backend to use\n"
" id= identifier of the backend\n"
" timer-period= timer period in microseconds\n"
+ " in|out.mixeng= use mixeng to mix streams inside QEMU\n"
" in|out.fixed-settings= use fixed settings for host
audio\n"
" in|out.frequency= frequency to use with fixed settings\n"
" in|out.channels= number of channels to use with fixed
settings\n"
@@ -397,6 +398,11 @@ Identifies the audio backend.
Sets the timer @var{period} used by the audio subsystem in microseconds.
Default is 10000 (10 ms).
address@hidden in|out.mixeng=on|off
+Use QEMU's mixing engine to mix all streams inside QEMU. When off,
address@hidden must be off too. Not every backend is fully
+compatible with the off setting. Default is on.
+
@item in|out.fixed-settings=on|off
Use fixed settings for host audio. When off, it will change based on
how the guest opens the sound card. In this case you must not specify
--
2.4.5
- Re: [Qemu-devel] [PATCH 18/25] audio: do not run each backend in audio_run, (continued)
- [Qemu-devel] [PATCH 25/25] audio: split ctl_* functions into enable_* and volume_*, Kővágó, Zoltán, 2015/08/06
- [Qemu-devel] [PATCH 17/25] audio: remove gcc specific audio_MIN, audio_MAX, Kővágó, Zoltán, 2015/08/06
- [Qemu-devel] [PATCH 14/25] audio: audiodev= parameters no longer optional when -audiodev present, Kővágó, Zoltán, 2015/08/06
- [Qemu-devel] [PATCH 22/25] audio: add mixeng option (documentation),
Kővágó, Zoltán <=
- [Qemu-devel] [PATCH 13/25] audio: add audiodev properties to frontends, Kővágó, Zoltán, 2015/08/06
- [Qemu-devel] [PATCH 21/25] audio: common rate control code for timer based outputs, Kővágó, Zoltán, 2015/08/06
- [Qemu-devel] [PATCH 05/25] qapi: change Netdev into a flat union, Kővágó, Zoltán, 2015/08/06
- [Qemu-devel] [PATCH 11/25] audio: reduce glob_audio_state usage, Kővágó, Zoltán, 2015/08/06