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From: "Zoltán Kővágó" <dirty.ice.hu@gmail.com>
To: Eric Blake <eblake@redhat.com>, qemu-devel@nongnu.org
Cc: Gerd Hoffmann <kraxel@redhat.com>, Markus Armbruster <armbru@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 16/25] audio: add mixeng option (documentation)
Date: Mon, 26 Aug 2019 22:04:49 +0200
Message-ID: <90eee26d-ff1f-8ada-08ba-32ca1f27ae8e@gmail.com> (raw)
In-Reply-To: <1e59409e-1754-543f-28e1-03db2b01d634@redhat.com>

On 2019-08-26 15:35, Eric Blake wrote:
> On 8/25/19 1:46 PM, Kővágó, Zoltán wrote:
>> 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 <DirtY.iCE.hu@gmail.com>
>> ---
>>  qapi/audio.json | 5 +++++
>>  qemu-options.hx | 6 ++++++
>>  2 files changed, 11 insertions(+)
>>
>> diff --git a/qapi/audio.json b/qapi/audio.json
>> index 9fefdf5186..dc7f9cb1e2 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.
>>  #
>> +# @mixeng: 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)
>> +#
> 
> 'mixeng' looks like an accidental typo, when 3 words later is 'mixing'.
> Would 'mix-eng' or 'mix-engine' be more obvious?

I used the spelling used in audio/mixeng.c, if we treat it as a name
then it should be simply 'mixeng'.  However I agree that it might not be
too meaningful for users, so 'mixing-engine' would make more sense, even
though it's a bit longer.

> 
> 
>>  ##
>>  { 'struct': 'AudiodevPerDirectionOptions',
>>    'data': {
>> +    '*mixeng':         'bool',
>>      '*fixed-settings': 'bool',
> 
> And the very next member is an example that QAPI doesn't have to use
> abbreviations.
> 

Regards,
Zoltan


  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-25 18:46 [Qemu-devel] [PATCH 00/25] Audio: Mixeng-free 5.1/7.1 audio support Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 01/25] audio: api for mixeng code free backends Kővágó, Zoltán
2019-08-27  5:43   ` Gerd Hoffmann
2019-08-25 18:46 ` [Qemu-devel] [PATCH 02/25] alsaaudio: port to the new audio backend api Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 03/25] coreaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 04/25] dsoundaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 05/25] noaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 06/25] ossaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 07/25] paaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 08/25] sdlaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 10/25] wavaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 11/25] audio: remove remains of the old " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 12/25] audio: unify input and output mixeng buffer management Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 13/25] audio: remove hw->samples, buffer_size_in/out pcm_ops Kővágó, Zoltán
2019-08-27  5:48   ` Gerd Hoffmann
2019-08-25 18:46 ` [Qemu-devel] [PATCH 14/25] audio: common rate control code for timer based outputs Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 15/25] audio: split ctl_* functions into enable_* and volume_* Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 16/25] audio: add mixeng option (documentation) Kővágó, Zoltán
2019-08-26 13:35   ` Eric Blake
2019-08-26 20:04     ` Zoltán Kővágó [this message]
2019-08-25 18:46 ` [Qemu-devel] [PATCH 17/25] audio: make mixeng optional Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 19/25] audio: support more than two channels in volume setting Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 20/25] audio: replace shift in audio_pcm_info with bytes_per_frame Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 21/25] audio: basic support for multichannel audio Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 22/25] paaudio: channel-map option Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 23/25] usb-audio: do not count on avail bytes actually available Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 25/25] usbaudio: change playback counters to 64 bit Kővágó, Zoltán

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