Message ID | 20190919083629.29998-16-kraxel@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | [PULL,01/26] audio: api for mixeng code free backends | expand |
On 9/19/19 3:36 AM, Gerd Hoffmann wrote: > From: Kővágó, Zoltán <dirty.ice.hu@gmail.com> > > 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. > > +++ b/qemu-options.hx > @@ -433,6 +433,7 @@ 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.mixing-engineeng= use mixing engine to mix streams inside QEMU\n" s/engineeng/engine/
diff --git a/qapi/audio.json b/qapi/audio.json index 9fefdf5186dd..0535eff7948f 100644 --- a/qapi/audio.json +++ b/qapi/audio.json @@ -11,6 +11,10 @@ # General audio backend options that are used for both playback and # recording. # +# @mixing-engine: 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, since 4.2) +# # @fixed-settings: use fixed settings for host input/output. When off, # frequency, channels and format must not be # specified (default true) @@ -31,6 +35,7 @@ ## { 'struct': 'AudiodevPerDirectionOptions', 'data': { + '*mixing-engine': 'bool', '*fixed-settings': 'bool', '*frequency': 'uint32', '*channels': 'uint32', diff --git a/qemu-options.hx b/qemu-options.hx index bbfd936d29ec..734a3b5d6569 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -433,6 +433,7 @@ 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.mixing-engineeng= use mixing engine 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" @@ -503,6 +504,11 @@ Identifies the audio backend. Sets the timer @var{period} used by the audio subsystem in microseconds. Default is 10000 (10 ms). +@item in|out.mixing-engine=on|off +Use QEMU's mixing engine to mix all streams inside QEMU. When off, +@var{fixed-settings} 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