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Pulseaudio, selecting Audio Device + multiple Audio

dfrizel

Joined: 14 Sep 2014

Posts: 7

Location: Vienna / Austria

Posted: Mon Sep 15, 2014 5:22 pm

I just did some work with audio on SDL2. I had some troubles with selecting an audio device on pulseaudio. Somehow it always seemed to fall back to the default device.
A had a quick look over the code and fixed the problem (at least for me). Additionally it adds support for multi-device audio and device detection. If you are interested here is the patch for (SDL2-2.0.3) but I found no difference with the current repo.

Code:

diff -r 5bf21e9e191f src/audio/pulseaudio/SDL_pulseaudio.c
--- a/src/audio/pulseaudio/SDL_pulseaudio.c Sun Sep 14 19:44:53 2014 +0200
+++ b/src/audio/pulseaudio/SDL_pulseaudio.c Sun Sep 14 21:40:27 2014 +0200
@@ -106,6 +106,7 @@

static int load_pulseaudio_syms(void);

+pa_operation* (*PULSEAUDIO_pa_context_get_sink_info_list)(pa_context *c, pa_sink_info_cb_t cb, void *userdata);

#ifdef SDL_AUDIO_DRIVER_PULSEAUDIO_DYNAMIC

@@ -202,11 +203,31 @@
SDL_PULSEAUDIO_SYM(pa_stream_disconnect);
SDL_PULSEAUDIO_SYM(pa_stream_unref);
SDL_PULSEAUDIO_SYM(pa_channel_map_init_auto);
+ SDL_PULSEAUDIO_SYM(pa_context_get_sink_info_list);
SDL_PULSEAUDIO_SYM(pa_strerror);
return 0;
}

+static void DeInit(struct SDL_PrivateAudioData *pulse_local_server)
+{
+ if (pulse_local_server != NULL)
+ {
+    if (pulse_local_server->context != NULL)
+    {
+       PULSEAUDIO_pa_context_disconnect(pulse_local_server->context);
+       PULSEAUDIO_pa_context_unref(pulse_local_server->context);
+       pulse_local_server->context = NULL;
+    }
+    if (pulse_local_server->mainloop != NULL) {
+       PULSEAUDIO_pa_mainloop_free(pulse_local_server->mainloop);
+       pulse_local_server->mainloop = NULL;
+    }
+    SDL_free(pulse_local_server);
+ }
+}
+
+
/* Check to see if we can connect to PulseAudio */
static SDL_bool
CheckPulseAudioAvailable()
@@ -307,16 +328,7 @@
PULSEAUDIO_pa_stream_unref(this->hidden->stream);
this->hidden->stream = NULL;
}
- if (this->hidden->context != NULL) {
- PULSEAUDIO_pa_context_disconnect(this->hidden->context);
- PULSEAUDIO_pa_context_unref(this->hidden->context);
- this->hidden->context = NULL;
- }
- if (this->hidden->mainloop != NULL) {
- PULSEAUDIO_pa_mainloop_free(this->hidden->mainloop);
- this->hidden->mainloop = NULL;
- }
- SDL_free(this->hidden);
+    DeInit(this->hidden);
this->hidden = NULL;
}
}
@@ -344,6 +356,53 @@
return "SDL Application"; /* oh well. */
}

+
+static struct SDL_PrivateAudioData *ThreadInit()
+{
+ struct SDL_PrivateAudioData *h = NULL;
+ int state = 0;
+
+ struct SDL_PrivateAudioData *pulse_local_server = SDL_malloc((sizeof *pulse_local_server));
+
+ if (pulse_local_server == NULL) {
+ return 0;
+ }
+ SDL_memset(pulse_local_server, 0, (sizeof *pulse_local_server));
+ h = pulse_local_server;
+
+ /* Set up a new main loop */
+ if (!(h->mainloop = PULSEAUDIO_pa_mainloop_new())) {
+    DeInit(pulse_local_server);
+    return 0;
+ }
+
+ h->mainloop_api = PULSEAUDIO_pa_mainloop_get_api(h->mainloop);
+ h->context = PULSEAUDIO_pa_context_new(h->mainloop_api, getAppName());
+ if (!h->context) {
+    DeInit(pulse_local_server);
+    return 0;
+ }
+
+ /* Connect to the PulseAudio server */
+ if (PULSEAUDIO_pa_context_connect(h->context, NULL, 0, NULL) < 0) {
+    DeInit(pulse_local_server);
+    return 0;
+ }
+
+ do {
+    if (PULSEAUDIO_pa_mainloop_iterate(h->mainloop, 1, NULL) < 0) {
+       DeInit(pulse_local_server);
+       return 0;
+    }
+    state = PULSEAUDIO_pa_context_get_state(h->context);
+    if (!PA_CONTEXT_IS_GOOD(state)) {
+       DeInit(pulse_local_server);
+       return 0;
+    }
+ } while (state != PA_CONTEXT_READY);
+ return pulse_local_server;
+}
+
static int
PULSEAUDIO_OpenDevice(_THIS, const char *devname, int iscapture)
{
@@ -356,12 +415,12 @@
int state = 0;

/* Initialize all variables that we clean on shutdown */
- this->hidden = (struct SDL_PrivateAudioData *)
- SDL_malloc((sizeof *this->hidden));
+ this->hidden = ThreadInit();
+
if (this->hidden == NULL) {
return SDL_OutOfMemory();
}
- SDL_memset(this->hidden, 0, (sizeof *this->hidden));
+
h = this->hidden;

paspec.format = PA_SAMPLE_INVALID;
@@ -448,36 +507,6 @@
PA_CHANNEL_MAP_WAVEEX);

/* Set up a new main loop */
- if (!(h->mainloop = PULSEAUDIO_pa_mainloop_new())) {
- PULSEAUDIO_CloseDevice(this);
- return SDL_SetError("pa_mainloop_new() failed");
- }
-
- h->mainloop_api = PULSEAUDIO_pa_mainloop_get_api(h->mainloop);
- h->context = PULSEAUDIO_pa_context_new(h->mainloop_api, getAppName());
- if (!h->context) {
- PULSEAUDIO_CloseDevice(this);
- return SDL_SetError("pa_context_new() failed");
- }
-
- /* Connect to the PulseAudio server */
- if (PULSEAUDIO_pa_context_connect(h->context, NULL, 0, NULL) < 0) {
- PULSEAUDIO_CloseDevice(this);
- return SDL_SetError("Could not setup connection to PulseAudio");
- }
-
- do {
- if (PULSEAUDIO_pa_mainloop_iterate(h->mainloop, 1, NULL) < 0) {
- PULSEAUDIO_CloseDevice(this);
- return SDL_SetError("pa_mainloop_iterate() failed");
- }
- state = PULSEAUDIO_pa_context_get_state(h->context);
- if (!PA_CONTEXT_IS_GOOD(state)) {
- PULSEAUDIO_CloseDevice(this);
- return SDL_SetError("Could not connect to PulseAudio");
- }
- } while (state != PA_CONTEXT_READY);
-
h->stream = PULSEAUDIO_pa_stream_new(
h->context,
"Simple DirectMedia Layer", /* stream description */
@@ -490,7 +519,7 @@
return SDL_SetError("Could not set up PulseAudio stream");
}

- if (PULSEAUDIO_pa_stream_connect_playback(h->stream, NULL, &paattr, flags,
+ if (PULSEAUDIO_pa_stream_connect_playback(h->stream, devname, &paattr, flags,
NULL, NULL) < 0) {
PULSEAUDIO_CloseDevice(this);
return SDL_SetError("Could not connect PulseAudio stream");
@@ -519,6 +548,58 @@
UnloadPulseAudioLibrary();
}

+
+
+typedef struct
+{
+ uint8_t last;
+ SDL_AddAudioDevice addfn;
+} sink_struct;
+
+static void get_sink_info_callback(pa_context *c, const pa_sink_info *i, int is_last, void *userdata)
+{
+ sink_struct *a = (sink_struct *) userdata;
+
+ a->last = is_last;
+ if(i)
+ {
+    a->addfn(i->name);
+ }
+}
+
+void PULSEAUDIO_DetectDevices(int iscapture, SDL_AddAudioDevice addfn)
+{
+ struct SDL_PrivateAudioData *h = NULL;
+ struct SDL_PrivateAudioData *pulse_local_server = ThreadInit();
+
+ if(pulse_local_server == NULL)
+ {
+    //Out of Memory
+    return;
+ }
+
+ sink_struct a;
+ h = pulse_local_server;
+
+ if(iscapture != 1)
+ {
+    a.last = 0;
+    a.addfn = addfn;
+    pa_operation* o = PULSEAUDIO_pa_context_get_sink_info_list(h->context, get_sink_info_callback, &a);
+    while(!a.last)
+    {
+       if(PULSEAUDIO_pa_operation_get_state(o) == PA_OPERATION_CANCELLED)
+       {
+          break;
+       }
+       if (PULSEAUDIO_pa_mainloop_iterate(h->mainloop, 1, NULL) < 0) {
+          break;
+       }
+    }
+ }
+ DeInit(pulse_local_server);
+}
+
static int
PULSEAUDIO_Init(SDL_AudioDriverImpl * impl)
{
@@ -530,8 +611,9 @@
UnloadPulseAudioLibrary();
return 0;
}
-
+
/* Set the function pointers */
+ impl->DetectDevices = PULSEAUDIO_DetectDevices;
impl->OpenDevice = PULSEAUDIO_OpenDevice;
impl->PlayDevice = PULSEAUDIO_PlayDevice;
impl->WaitDevice = PULSEAUDIO_WaitDevice;
@@ -539,7 +621,7 @@
impl->CloseDevice = PULSEAUDIO_CloseDevice;
impl->WaitDone = PULSEAUDIO_WaitDone;
impl->Deinitialize = PULSEAUDIO_Deinitialize;
- impl->OnlyHasDefaultOutputDevice = 1;
+ impl->OnlyHasDefaultOutputDevice = 0;

return 1; /* this audio target is available. */
}
diff -r 5bf21e9e191f src/audio/pulseaudio/SDL_pulseaudio.h
--- a/src/audio/pulseaudio/SDL_pulseaudio.h Sun Sep 14 19:44:53 2014 +0200
+++ b/src/audio/pulseaudio/SDL_pulseaudio.h Sun Sep 14 21:40:27 2014 +0200
@@ -30,6 +30,7 @@
/* Hidden "this" pointer for the audio functions */
#define _THIS SDL_AudioDevice *this

+
struct SDL_PrivateAudioData
{
/* pulseaudio structures */

And I assume it is necessary to add: It is ok the add it to the SDL2 Codebase under the zlib license

dfrizel

Joined: 14 Sep 2014

Posts: 7

Location: Vienna / Austria

Posted: Tue Sep 16, 2014 5:39 pm

Added it to bugzilla - have only found it today Embarrassed

Pulseaudio, selecting Audio Device + multiple Audio

Daniel Holth

Guest

Posted: Tue Sep 16, 2014 8:20 pm

That's great, I've found it very frustrating trying to use HDMI audio - maybe this will fix it.

On Tue, Sep 16, 2014 at 1:39 PM, dfrizel wrote:

Quote:

Added it to bugzilla - have only found it today

void (*segfault)(void) = 0;
int main(int argc, char **argv){segfault(); return 0;}
//Should not work, but does what told

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This is just a read-only archive of the previous forums, to keep old links working.