Warn on audio device failure rather than abort.

src/applications/gqrx/main.cpp

@@ -98,41 +98,6 @@ int main(int argc, char *argv[])
         return 0;
     }
 
-    // check whether audio backend is functional
-#ifdef WITH_PORTAUDIO
-    PaError     err = Pa_Initialize();
-    if (err != paNoError)
-    {
-        QString message = QString("Portaudio error: %1").arg(Pa_GetErrorText(err));
-        qCritical() << message;
-        QMessageBox::critical(nullptr, "Audio Error", message,
-                              QMessageBox::Abort, QMessageBox::NoButton);
-        return 1;
-    }
-#endif
-
-#ifdef WITH_PULSEAUDIO
-    int         error = 0;
-    pa_simple  *test_sink;
-    pa_sample_spec ss;
-
-    ss.format = PA_SAMPLE_FLOAT32LE;
-    ss.rate = 48000;
-    ss.channels = 2;
-    test_sink =  pa_simple_new(NULL, "Gqrx Test", PA_STREAM_PLAYBACK, NULL,
-                               "Test stream", &ss, NULL, NULL, &error);
-    if (!test_sink)
-    {
-        QString message = QString("Pulseaudio error: %1").arg(pa_strerror(error));
-        qCritical() << message;
-        QMessageBox::critical(0, "Audio Error", message,
-                              QMessageBox::Abort, QMessageBox::NoButton);
-        return 1;
-    }
-    pa_simple_free(test_sink);
-#endif
-
-
     if (parser.isSet("conf"))
     {
         cfg_file = parser.value("conf");

src/applications/gqrx/mainwindow.cpp

@@ -553,7 +553,8 @@ bool MainWindow::loadConfig(const QString& cfgfile, bool check_crash,
         }
 
         // Update window title
-        setWindowTitle(QString("Gqrx %1 - %2").arg(VERSION).arg(indev));
+        const char* audio_status = rx->has_audio_device() ? "" : " - NO AUDIO";
+        setWindowTitle(QString("Gqrx %1 - %2%3").arg(VERSION).arg(indev).arg(audio_status));
 
         // Add available antenna connectors to the UI
         std::vector<std::string> antennas = rx->get_antennas();

src/applications/gqrx/receiver.cpp

@@ -72,7 +72,8 @@ receiver::receiver(const std::string input_device,
       d_iq_rev(false),
       d_dc_cancel(false),
       d_iq_balance(false),
-      d_demod(RX_DEMOD_OFF)
+      d_demod(RX_DEMOD_OFF),
+      d_has_audio_device(false)
 {
 
     tb = gr::make_top_block("gqrx");
@@ -125,13 +126,20 @@ receiver::receiver(const std::string input_device,
 
     audio_udp_sink = make_udp_sink_f();
 
+    try {
 #ifdef WITH_PULSEAUDIO
-    audio_snk = make_pa_sink(audio_device, d_audio_rate, "GQRX", "Audio output");
+        audio_snk = make_pa_sink(audio_device, d_audio_rate, "GQRX", "Audio output");
 #elif WITH_PORTAUDIO
-    audio_snk = make_portaudio_sink(audio_device, d_audio_rate, "GQRX", "Audio output");
+        audio_snk = make_portaudio_sink(audio_device, d_audio_rate, "GQRX", "Audio output");
 #else
-    audio_snk = gr::audio::sink::make(d_audio_rate, audio_device, true);
+        audio_snk = gr::audio::sink::make(d_audio_rate, audio_device, true);
 #endif
+        d_has_audio_device = true;
+    }
+    // No audio device a null sink.
+    catch (const std::exception& error) {
+        audio_snk = gr::blocks::null_sink::make(sizeof(float));
+    }
 
     output_devstr = audio_device;
 
@@ -142,10 +150,6 @@ receiver::receiver(const std::string input_device,
     /* sniffer_rr is created at each activation. */
 
     set_demod(RX_DEMOD_NFM);
-
-    gr::prefs pref;
-    qDebug() << "Using audio backend:"
-             << pref.get_string("audio", "audio_module", "N/A").c_str();
 }
 
 receiver::~receiver()
@@ -284,20 +288,17 @@ void receiver::set_output_device(const std::string device)
 #else
         audio_snk = gr::audio::sink::make(d_audio_rate, device, true);
 #endif
-
-        if (d_demod != RX_DEMOD_OFF)
-        {
-            tb->connect(audio_gain0, 0, audio_snk, 0);
-            tb->connect(audio_gain1, 0, audio_snk, 1);
-        }
-
-        tb->unlock();
-
-    } catch (std::exception &x) {
-        tb->unlock();
-        // handle problems on non-freeing devices
-        throw x;
     }
+    catch (const std::exception& error) {
+        audio_snk = gr::blocks::null_sink::make(sizeof(float));
+    }
+    if (d_demod != RX_DEMOD_OFF)
+    {
+        tb->connect(audio_gain0, 0, audio_snk, 0);
+        tb->connect(audio_gain1, 0, audio_snk, 1);
+    }
+
+    tb->unlock();
 }
 
 /** Get a list of available antenna connectors. */

src/applications/gqrx/receiver.h

@@ -206,6 +206,8 @@ class receiver
     status      start_udp_streaming(const std::string host, int port, bool stereo);
     status      stop_udp_streaming();
 
+    bool        has_audio_device(void) { return d_has_audio_device; }
+
     /* I/Q recording and playback */
     status      start_iq_recording(const std::string filename);
     status      stop_iq_recording();
@@ -285,13 +287,8 @@ class receiver
     sniffer_f_sptr    sniffer;    /*!< Sample sniffer for data decoders. */
     resampler_ff_sptr sniffer_rr; /*!< Sniffer resampler. */
 
-#ifdef WITH_PULSEAUDIO
-    pa_sink_sptr              audio_snk;  /*!< Pulse audio sink. */
-#elif WITH_PORTAUDIO
-    portaudio_sink_sptr       audio_snk;  /*!< portaudio sink */
-#else
-    gr::audio::sink::sptr     audio_snk;  /*!< gr audio sink */
-#endif
+    bool                       d_has_audio_device;
+    gr::basic_block_sptr       audio_snk;  /*!< Audio sink (pulse, portaudio, gr-audio). */
 
     //! Get a path to a file containing random bytes
     static std::string get_zero_file(void);

src/pulseaudio/pa_sink.cc

@@ -69,8 +69,7 @@ pa_sink::pa_sink(const string device_name, int audio_rate,
                              &error);
 
     if (!d_pasink) {
-        /** FIXME: Throw an exception **/
-        fprintf(stderr, __FILE__": pa_simple_new() failed: %s\n", pa_strerror(error));
+        throw std::runtime_error("Unable to open pulseaudio device.");
     }
 
 }