[PATCH] dbus: add -audio dbus nsamples option

[PATCH] dbus: add -audio dbus nsamples option

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Allow to set the number of audio samples per read/write to dbus.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 qapi/audio.json      | 22 +++++++++++++++++++++-
 audio/dbusaudio.c    | 21 ++++++++++++++++++---
 ui/dbus-display1.xml | 12 ++++++++++++
 3 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/qapi/audio.json b/qapi/audio.json
index 519697c0cd..dd5a58d13e 100644
--- a/qapi/audio.json
+++ b/qapi/audio.json
@@ -65,6 +65,26 @@
     '*in':  'AudiodevPerDirectionOptions',
     '*out': 'AudiodevPerDirectionOptions' } }
 
+##
+# @AudiodevDBusOptions:
+#
+# Options of the D-Bus audio backend.
+#
+# @in: options of the capture stream
+#
+# @out: options of the playback stream
+#
+# @nsamples: set the number of samples per read/write calls (default to 480,
+# 10ms at 48kHz).
+#
+# Since: 10.0
+##
+{ 'struct': 'AudiodevDBusOptions',
+  'data': {
+    '*in':  'AudiodevPerDirectionOptions',
+    '*out': 'AudiodevPerDirectionOptions',
+    '*nsamples': 'uint32'} }
+
 ##
 # @AudiodevAlsaPerDirectionOptions:
 #
@@ -490,7 +510,7 @@
                    'if': 'CONFIG_AUDIO_ALSA' },
     'coreaudio': { 'type': 'AudiodevCoreaudioOptions',
                    'if': 'CONFIG_AUDIO_COREAUDIO' },
-    'dbus':      { 'type': 'AudiodevGenericOptions',
+    'dbus':      { 'type': 'AudiodevDBusOptions',
                    'if': 'CONFIG_DBUS_DISPLAY' },
     'dsound':    { 'type': 'AudiodevDsoundOptions',
                    'if': 'CONFIG_AUDIO_DSOUND' },
diff --git a/audio/dbusaudio.c b/audio/dbusaudio.c
index af77e7cc33..b44fdd1511 100644
--- a/audio/dbusaudio.c
+++ b/audio/dbusaudio.c
@@ -43,9 +43,10 @@
 
 #define DBUS_DISPLAY1_AUDIO_PATH DBUS_DISPLAY1_ROOT "/Audio"
 
-#define DBUS_AUDIO_NSAMPLES 1024 /* could be configured? */
+#define DBUS_DEFAULT_AUDIO_NSAMPLES 480
 
 typedef struct DBusAudio {
+    Audiodev *dev;
     GDBusObjectManagerServer *server;
     bool p2p;
     GDBusObjectSkeleton *audio;
@@ -151,6 +152,18 @@ dbus_init_out_listener(QemuDBusDisplay1AudioOutListener *listener,
         G_DBUS_CALL_FLAGS_NONE, -1, NULL, NULL, NULL);
 }
 
+static guint
+dbus_audio_get_nsamples(DBusAudio *da)
+{
+    AudiodevDBusOptions *opts = &da->dev->u.dbus;
+
+    if (opts->has_nsamples && opts->nsamples) {
+        return opts->nsamples;
+    } else {
+        return DBUS_DEFAULT_AUDIO_NSAMPLES;
+    }
+}
+
 static int
 dbus_init_out(HWVoiceOut *hw, struct audsettings *as, void *drv_opaque)
 {
@@ -160,7 +173,7 @@ dbus_init_out(HWVoiceOut *hw, struct audsettings *as, void *drv_opaque)
     QemuDBusDisplay1AudioOutListener *listener = NULL;
 
     audio_pcm_init_info(&hw->info, as);
-    hw->samples = DBUS_AUDIO_NSAMPLES;
+    hw->samples = dbus_audio_get_nsamples(da);
     audio_rate_start(&vo->rate);
 
     g_hash_table_iter_init(&iter, da->out_listeners);
@@ -274,7 +287,7 @@ dbus_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
     QemuDBusDisplay1AudioInListener *listener = NULL;
 
     audio_pcm_init_info(&hw->info, as);
-    hw->samples = DBUS_AUDIO_NSAMPLES;
+    hw->samples = dbus_audio_get_nsamples(da);
     audio_rate_start(&vo->rate);
 
     g_hash_table_iter_init(&iter, da->in_listeners);
@@ -399,6 +412,7 @@ dbus_audio_init(Audiodev *dev, Error **errp)
 {
     DBusAudio *da = g_new0(DBusAudio, 1);
 
+    da->dev = dev;
     da->out_listeners = g_hash_table_new_full(g_str_hash, g_str_equal,
                                                 g_free, g_object_unref);
     da->in_listeners = g_hash_table_new_full(g_str_hash, g_str_equal,
@@ -652,6 +666,7 @@ dbus_audio_set_server(AudioState *s, GDBusObjectManagerServer *server, bool p2p)
                      "swapped-signal::handle-register-out-listener",
                      dbus_audio_register_out_listener, s,
                      NULL);
+    qemu_dbus_display1_audio_set_nsamples(da->iface, dbus_audio_get_nsamples(da));
 
     g_dbus_object_skeleton_add_interface(G_DBUS_OBJECT_SKELETON(da->audio),
                                          G_DBUS_INTERFACE_SKELETON(da->iface));
diff --git a/ui/dbus-display1.xml b/ui/dbus-display1.xml
index d702253431..72deefa455 100644
--- a/ui/dbus-display1.xml
+++ b/ui/dbus-display1.xml
@@ -773,6 +773,18 @@
       <?endif?>
     </method>
 
+    <!--
+        NSamples:
+
+        The number of samples per read/write frames. (for example the default is
+        480, or 10ms at 48kHz)
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="NSamples" type="u" access="read">
+      <annotation name="org.freedesktop.DBus.Property.EmitsChangedSignal" value="const"/>
+    </property>
+
     <!--
         Interfaces:
 
-- 
2.47.0

Re: [PATCH] dbus: add -audio dbus nsamples option

[Markus Armbruster]

marcandre.lureau@redhat.com writes:

> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> Allow to set the number of audio samples per read/write to dbus.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  qapi/audio.json      | 22 +++++++++++++++++++++-
>  audio/dbusaudio.c    | 21 ++++++++++++++++++---
>  ui/dbus-display1.xml | 12 ++++++++++++
>  3 files changed, 51 insertions(+), 4 deletions(-)
>
> diff --git a/qapi/audio.json b/qapi/audio.json
> index 519697c0cd..dd5a58d13e 100644
> --- a/qapi/audio.json
> +++ b/qapi/audio.json
> @@ -65,6 +65,26 @@
>      '*in':  'AudiodevPerDirectionOptions',
>      '*out': 'AudiodevPerDirectionOptions' } }
>  
> +##
> +# @AudiodevDBusOptions:
> +#
> +# Options of the D-Bus audio backend.
> +#
> +# @in: options of the capture stream
> +#
> +# @out: options of the playback stream
> +#
> +# @nsamples: set the number of samples per read/write calls (default to 480,
> +# 10ms at 48kHz).

Markup error.  This is rendered like

    "nsamples": "int" (optional)
       set the number of samples per read/write calls (default to 480,

    10ms at 48kHz).

Fix:

   # @nsamples: set the number of samples per read/write calls
   #     (default to 480, 10ms at 48kHz).

I'm not sure I understand the parenthesis.  I guess it means default
value is 480 samples per read/write call, which translates to 10ms when
sampling at 48kHz.  Correct?

> +#
> +# Since: 10.0
> +##
> +{ 'struct': 'AudiodevDBusOptions',
> +  'data': {
> +    '*in':  'AudiodevPerDirectionOptions',
> +    '*out': 'AudiodevPerDirectionOptions',
> +    '*nsamples': 'uint32'} }
> +

Could use 'base': 'AudiodevGenericOptions' instead of duplicating @in
and @out, but that would deviate from all the other AudiodevFOOOptions.
I agree with your decision.

>  ##
>  # @AudiodevAlsaPerDirectionOptions:
>  #
> @@ -490,7 +510,7 @@
>                     'if': 'CONFIG_AUDIO_ALSA' },
>      'coreaudio': { 'type': 'AudiodevCoreaudioOptions',
>                     'if': 'CONFIG_AUDIO_COREAUDIO' },
> -    'dbus':      { 'type': 'AudiodevGenericOptions',
> +    'dbus':      { 'type': 'AudiodevDBusOptions',
>                     'if': 'CONFIG_DBUS_DISPLAY' },
>      'dsound':    { 'type': 'AudiodevDsoundOptions',
>                     'if': 'CONFIG_AUDIO_DSOUND' },

[...]

Re: [PATCH] dbus: add -audio dbus nsamples option

[Marc-André Lureau]

Hi

On Wed, Feb 5, 2025 at 12:33 PM Markus Armbruster <armbru@redhat.com> wrote:
>
> marcandre.lureau@redhat.com writes:
>
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> >
> > Allow to set the number of audio samples per read/write to dbus.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  qapi/audio.json      | 22 +++++++++++++++++++++-
> >  audio/dbusaudio.c    | 21 ++++++++++++++++++---
> >  ui/dbus-display1.xml | 12 ++++++++++++
> >  3 files changed, 51 insertions(+), 4 deletions(-)
> >
> > diff --git a/qapi/audio.json b/qapi/audio.json
> > index 519697c0cd..dd5a58d13e 100644
> > --- a/qapi/audio.json
> > +++ b/qapi/audio.json
> > @@ -65,6 +65,26 @@
> >      '*in':  'AudiodevPerDirectionOptions',
> >      '*out': 'AudiodevPerDirectionOptions' } }
> >
> > +##
> > +# @AudiodevDBusOptions:
> > +#
> > +# Options of the D-Bus audio backend.
> > +#
> > +# @in: options of the capture stream
> > +#
> > +# @out: options of the playback stream
> > +#
> > +# @nsamples: set the number of samples per read/write calls (default to 480,
> > +# 10ms at 48kHz).
>
> Markup error.  This is rendered like
>
>     "nsamples": "int" (optional)
>        set the number of samples per read/write calls (default to 480,
>
>     10ms at 48kHz).
>
> Fix:
>
>    # @nsamples: set the number of samples per read/write calls
>    #     (default to 480, 10ms at 48kHz).
>

ack, could you send a patch?

> I'm not sure I understand the parenthesis.  I guess it means default
> value is 480 samples per read/write call, which translates to 10ms when
> sampling at 48kHz.  Correct?

correct, feel free to improve the wording.

> > +#
> > +# Since: 10.0
> > +##
> > +{ 'struct': 'AudiodevDBusOptions',
> > +  'data': {
> > +    '*in':  'AudiodevPerDirectionOptions',
> > +    '*out': 'AudiodevPerDirectionOptions',
> > +    '*nsamples': 'uint32'} }
> > +
>
> Could use 'base': 'AudiodevGenericOptions' instead of duplicating @in
> and @out, but that would deviate from all the other AudiodevFOOOptions.
> I agree with your decision.
>
> >  ##
> >  # @AudiodevAlsaPerDirectionOptions:
> >  #
> > @@ -490,7 +510,7 @@
> >                     'if': 'CONFIG_AUDIO_ALSA' },
> >      'coreaudio': { 'type': 'AudiodevCoreaudioOptions',
> >                     'if': 'CONFIG_AUDIO_COREAUDIO' },
> > -    'dbus':      { 'type': 'AudiodevGenericOptions',
> > +    'dbus':      { 'type': 'AudiodevDBusOptions',
> >                     'if': 'CONFIG_DBUS_DISPLAY' },
> >      'dsound':    { 'type': 'AudiodevDsoundOptions',
> >                     'if': 'CONFIG_AUDIO_DSOUND' },
>
> [...]
>