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[Qemu-devel] [PATCH v2 43/52] audio: add mixeng option (documentation)
From: |
Kővágó, Zoltán |
Subject: |
[Qemu-devel] [PATCH v2 43/52] audio: add mixeng option (documentation) |
Date: |
Sun, 23 Dec 2018 21:52:19 +0100 |
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 56d8ce439f..180bf207a8 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 687dd23bf2..eb65b511fa 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -432,6 +432,7 @@ 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"
@@ -500,6 +501,11 @@ 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
--
2.20.1
- [Qemu-devel] [PATCH v2 46/52] audio: support more than two channels in volume setting, (continued)
- [Qemu-devel] [PATCH v2 46/52] audio: support more than two channels in volume setting, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 48/52] audio: basic support for multichannel audio, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 37/52] wavaudio: port to the new audio backend api, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 35/52] sdlaudio: port to the new audio backend api, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 38/52] audio: remove remains of the old backend api, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 41/52] audio: common rate control code for timer based outputs, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 29/52] alsaaudio: port to the new audio backend api, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 34/52] paaudio: port to the new audio backend api, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 42/52] audio: split ctl_* functions into enable_* and volume_*, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 47/52] audio: replace shift in audio_pcm_info with bytes_per_frame, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 43/52] audio: add mixeng option (documentation),
Kővágó, Zoltán <=
- [Qemu-devel] [PATCH v2 50/52] usb-audio: do not count on avail bytes actually available, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 49/52] paaudio: channel-map option, Kővágó, Zoltán, 2018/12/23
- [Qemu-devel] [PATCH v2 52/52] usbaudio: change playback counters to 64 bit, Kővágó, Zoltán, 2018/12/23
- Re: [Qemu-devel] [PATCH v2 00/52] Audio 5.1 patches, Philippe Mathieu-Daudé, 2018/12/25
- Re: [Qemu-devel] [PATCH v2 00/52] Audio 5.1 patches, Programmingkid, 2018/12/26