ao_pipewire: avoid setting any media.role by default

This adds option `--audio-set-media-role` to configure whether mpv
should set media roles to supported audio APIs or not. Disabled by
default.

By default, WirePlumber restores the volume of each application to
whatever the last application with the same media role used. This is
completely insane behavior, and I couldn’t find any way for a user to
opt out of it on my end. The `state-stream.lua` script responsible for
this mess only uses media.role if the property is present, so the only
reliable workaround is simply not to set one at all.

This WirePlumber behavior is inherited from PulseAudio, which also
exhibits the same behavior to this day.

This commit also mirrors the same change made to ao_pulse in 2015:
b7325b2

See also: https://gitlab.freedesktop.org/pipewire/wireplumber/-/issues/489

Author: llyyr

DOCS/interface-changes/audio-set-media-role.txt

@@ -0,0 +1 @@
+add --audio-set-media-role

DOCS/man/options.rst

@@ -2387,6 +2387,11 @@ Audio
     if you want to force a different audio profile (e.g. with PulseAudio),
     or to set your own application name when using libmpv.
 
+``--audio-set-media-role=<yes|no>``
+    If enabled, mpv will set the appropriate media role on supported audio
+    servers depending on whether mpv is playing a video with audio or an
+    audio only file. Default: no.
+
 ``--audio-buffer=<seconds>``
     Set the audio output minimum buffer. The audio device might actually create
     a larger buffer if it pleases. If the device creates a smaller buffer,

audio/out/ao.c

@@ -145,6 +145,8 @@ const struct m_sub_options ao_conf = {
         {"audio-client-name", OPT_STRING(audio_client_name), .flags = UPDATE_AUDIO},
         {"audio-buffer", OPT_DOUBLE(audio_buffer),
             .flags = UPDATE_AUDIO, M_RANGE(0, 10)},
+        {"audio-set-media-role", OPT_BOOL(audio_set_media_role),
+            .flags = UPDATE_AUDIO},
         {0}
     },
     .size = sizeof(OPT_BASE_STRUCT),
@@ -180,6 +182,7 @@ static struct ao *ao_alloc(bool probing, struct mpv_global *global,
         .log = mp_log_new(ao, log, name),
         .def_buffer = opts->audio_buffer,
         .client_name = talloc_strdup(ao, opts->audio_client_name),
+        .set_media_role = opts->audio_set_media_role
     };
     talloc_free(opts);
     ao->priv = m_config_group_from_desc(ao, ao->log, global, &desc, name);

audio/out/ao.h

@@ -79,6 +79,7 @@ struct ao_opts {
     char *audio_device;
     char *audio_client_name;
     double audio_buffer;
+    bool audio_set_media_role;
 };
 
 struct ao *ao_init_best(struct mpv_global *global,

audio/out/ao_pipewire.c

@@ -577,7 +577,6 @@ static int init(struct ao *ao)
     struct pw_properties *props = pw_properties_new(
         PW_KEY_MEDIA_TYPE, "Audio",
         PW_KEY_MEDIA_CATEGORY, "Playback",
-        PW_KEY_MEDIA_ROLE, ao->init_flags & AO_INIT_MEDIA_ROLE_MUSIC ?  "Music" : "Movie",
         PW_KEY_NODE_NAME, ao->client_name,
         PW_KEY_NODE_DESCRIPTION, ao->client_name,
         PW_KEY_APP_NAME, ao->client_name,
@@ -588,6 +587,10 @@ static int init(struct ao *ao)
         NULL
     );
 
+    if (ao->set_media_role)
+        pw_properties_set(props, PW_KEY_MEDIA_ROLE,
+                          ao->init_flags & AO_INIT_MEDIA_ROLE_MUSIC ? "Music" : "Movie");
+
     if (pipewire_init_boilerplate(ao) < 0)
         goto error_props;
 

audio/out/internal.h

@@ -55,6 +55,9 @@ struct ao {
     // Application name to report to the audio API.
     char *client_name;
 
+    // Whether mpv should set the media role to the audio server
+    bool set_media_role;
+
     // Used during init: if init fails, redirect to this ao
     char *redirect;