Re: [PATCH 03/23] sdlaudio: add -audiodev sdl, out.buffer-count option

[Markus Armbruster <armbru@redhat.com>]

Volker Rümelin <vr_qemu@t-online.de> writes:

> Currently there is a crackling noise with SDL2 audio playback.
> Commit bcf19777df: "audio/sdlaudio: Allow audio playback with
> SDL2" already mentioned the crackling noise.
>
> Add an out.buffer-count option to give users a chance to select
> sane settings for glitch free audio playback. The idea was taken
> from the coreaudio backend.
>
> The in.buffer-count option will be used with one of the next
> patches.
>
> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
> ---
[...]
> diff --git a/qapi/audio.json b/qapi/audio.json
> index 072ed79def..9cba0df8a4 100644
> --- a/qapi/audio.json
> +++ b/qapi/audio.json
> @@ -301,6 +301,37 @@
>      '*out':    'AudiodevPaPerDirectionOptions',
>      '*server': 'str' } }
>  
> +##
> +# @AudiodevSdlPerDirectionOptions:
> +#
> +# Options of the SDL audio backend that are used for both playback and
> +# recording.
> +#
> +# @buffer-count: number of buffers (default 4)
> +#
> +# Since: 6.0
> +##
> +{ 'struct': 'AudiodevSdlPerDirectionOptions',
> +  'base': 'AudiodevPerDirectionOptions',
> +  'data': {
> +    '*buffer-count': 'uint32' } }
> +
> +##
> +# @AudiodevSdlOptions:
> +#
> +# Options of the SDL audio backend.
> +#
> +# @in: options of the recording stream
> +#
> +# @out: options of the playback stream
> +#
> +# Since: 6.0
> +##
> +{ 'struct': 'AudiodevSdlOptions',
> +  'data': {
> +    '*in':  'AudiodevSdlPerDirectionOptions',
> +    '*out': 'AudiodevSdlPerDirectionOptions' } }
> +
>  ##
>  # @AudiodevWavOptions:
>  #
> @@ -385,6 +416,6 @@
>      'jack':      'AudiodevJackOptions',
>      'oss':       'AudiodevOssOptions',
>      'pa':        'AudiodevPaOptions',
> -    'sdl':       'AudiodevGenericOptions',
> +    'sdl':       'AudiodevSdlOptions',
>      'spice':     'AudiodevGenericOptions',
>      'wav':       'AudiodevWavOptions' } }
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 1698a0c751..4e02e9bd76 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -588,6 +588,7 @@ DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
>  #endif
>  #ifdef CONFIG_AUDIO_SDL
>      "-audiodev sdl,id=id[,prop[=value][,...]]\n"
> +    "                in|out.buffer-count= number of buffers\n"
>  #endif
>  #ifdef CONFIG_SPICE
>      "-audiodev spice,id=id[,prop[=value][,...]]\n"
> @@ -745,7 +746,12 @@ SRST
>  ``-audiodev sdl,id=id[,prop[=value][,...]]``
>      Creates a backend using SDL. This backend is available on most
>      systems, but you should use your platform's native backend if
> -    possible. This backend has no backend specific properties.
> +    possible.
> +
> +    SDL specific options are:
> +
> +    ``in|out.buffer-count=count``
> +        Sets the count of the buffers.
>  
>  ``-audiodev spice,id=id[,prop[=value][,...]]``
>      Creates a backend that sends audio through SPICE. This backend

These parts:
Acked-by: Markus Armbruster <armbru@redhat.com>