Add ALSA PCM devices and option to set channels

Fixes #262

src/engine/alsapcmdevicefinder.cpp

@@ -0,0 +1,85 @@
+/*
+ * Strawberry Music Player
+ * Copyright 2021, Jonas Kvinge <jonas@jkvinge.net>
+ *
+ * Strawberry is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Strawberry is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "config.h"
+
+#include <cstdio>
+#include <cerrno>
+#include <alsa/asoundlib.h>
+
+#include <QList>
+#include <QVariant>
+#include <QString>
+#include <QtDebug>
+
+#include <core/logging.h>
+
+#include "devicefinder.h"
+#include "alsapcmdevicefinder.h"
+
+AlsaPCMDeviceFinder::AlsaPCMDeviceFinder()
+    : DeviceFinder("alsa", {"alsa","alsasink"}) {}
+
+QList<DeviceFinder::Device> AlsaPCMDeviceFinder::ListDevices() {
+
+  QList<Device> ret;
+
+  void **hints = nullptr;
+  if (snd_device_name_hint(-1, "pcm", &hints) < 0) {
+    return ret;
+  }
+
+  for (void **n = hints ; *n ; ++n) {
+    char *io = snd_device_name_get_hint(*n, "IOID");
+    char *name = snd_device_name_get_hint(*n, "NAME");
+    char *desc = snd_device_name_get_hint(*n, "DESC");
+    if (io && name && desc && strcmp(io, "Output") == 0) {
+
+      char *desc_last = desc;
+      QString description;
+      for (char *desc_i = desc ; desc_i && *desc_i != '\0' ; ++desc_i) {
+        if (*desc_i == '\n') {
+          *desc_i = '\0';
+          if (!description.isEmpty()) description.append(' ');
+          description.append(desc_last);
+          desc_last = desc_i + 1;
+        }
+      }
+
+      if (desc_last) {
+        if (!description.isEmpty()) description.append(' ');
+        description.append(desc_last);
+      }
+
+      Device device;
+      device.value = name;
+      device.description = description;
+      device.iconname = GuessIconName(device.description);
+      ret << device;
+    }
+    if (io) free(io);
+    if (name) free(name);
+    if (desc) free(desc);
+  }
+
+  snd_device_name_free_hint(hints);
+
+  return ret;
+
+}

src/engine/alsapcmdevicefinder.h

@@ -0,0 +1,37 @@
+/*
+ * Strawberry Music Player
+ * Copyright 2021, Jonas Kvinge <jonas@jkvinge.net>
+ *
+ * Strawberry is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Strawberry is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef ALSAPCMDEVICEFINDER_H
+#define ALSAPCMDEVICEFINDER_H
+
+#include "config.h"
+
+#include <QList>
+
+#include "devicefinder.h"
+
+class AlsaPCMDeviceFinder : public DeviceFinder {
+ public:
+  explicit AlsaPCMDeviceFinder();
+
+  bool Initialize() override { return true; }
+  QList<Device> ListDevices() override;
+};
+
+#endif // ALSAPCMDEVICEFINDER_H

src/engine/devicefinders.cpp

@@ -30,6 +30,7 @@
 
 #ifdef HAVE_ALSA
 #  include "alsadevicefinder.h"
+#  include "alsapcmdevicefinder.h"
 #endif
 
 #ifdef HAVE_LIBPULSE
@@ -57,6 +58,7 @@ void DeviceFinders::Init() {
 
 #ifdef HAVE_ALSA
   device_finders.append(new AlsaDeviceFinder);
+  device_finders.append(new AlsaPCMDeviceFinder);
 #endif
 #ifdef HAVE_LIBPULSE
   device_finders.append(new PulseDeviceFinder);

src/engine/enginebase.cpp

@@ -60,6 +60,8 @@ Engine::Base::Base()
       fadeout_duration_(2),
       fadeout_duration_nanosec_(2 * kNsecPerSec),
       proxy_authentication_(false),
+      channels_enabled_(false),
+      channels_(0),
       about_to_end_emitted_(false) {}
 
 Engine::Base::~Base() {}
@@ -110,6 +112,9 @@ void Engine::Base::ReloadSettings() {
 
   volume_control_ = s.value("volume_control", true).toBool();
 
+  channels_enabled_ = s.value("channels_enabled", false).toBool();
+  channels_ = s.value("channels", 0).toInt();
+
   buffer_duration_nanosec_ = s.value("bufferduration", BackendSettingsPage::kDefaultBufferDuration).toLongLong() * kNsecPerMsec;
   buffer_low_watermark_ = s.value("bufferlowwatermark", BackendSettingsPage::kDefaultBufferLowWatermark).toDouble();
   buffer_high_watermark_ = s.value("bufferhighwatermark", BackendSettingsPage::kDefaultBufferHighWatermark).toDouble();
@@ -156,6 +161,7 @@ void Engine::Base::ReloadSettings() {
     proxy_user_.clear();
     proxy_pass_.clear();
   }
+
   s.endGroup();
 
 }

src/engine/enginebase.h

@@ -206,6 +206,10 @@ class Base : public QObject {
   QString proxy_user_;
   QString proxy_pass_;
 
+  // Channels
+  bool channels_enabled_;
+  int channels_;
+
  private:
   bool about_to_end_emitted_;
   Q_DISABLE_COPY(Base)

src/engine/gstengine.cpp

@@ -817,6 +817,7 @@ std::shared_ptr<GstEnginePipeline> GstEngine::CreatePipeline() {
   ret->set_buffer_low_watermark(buffer_low_watermark_);
   ret->set_buffer_high_watermark(buffer_high_watermark_);
   ret->set_proxy_settings(proxy_address_, proxy_authentication_, proxy_user_, proxy_pass_);
+  ret->set_channels(channels_enabled_, channels_);
 
   ret->AddBufferConsumer(this);
   for (GstBufferConsumer *consumer : buffer_consumers_) {

src/engine/gstenginepipeline.cpp

@@ -86,6 +86,8 @@ GstEnginePipeline::GstEnginePipeline(GstEngine *engine)
       buffer_high_watermark_(BackendSettingsPage::kDefaultBufferHighWatermark),
       buffering_(false),
       proxy_authentication_(false),
+      channels_enabled_(false),
+      channels_(0),
       segment_start_(0),
       segment_start_received_(false),
       end_offset_nanosec_(-1),
@@ -206,6 +208,11 @@ void GstEnginePipeline::set_proxy_settings(const QString &address, const bool au
   proxy_pass_ = pass;
 }
 
+void GstEnginePipeline::set_channels(const bool enabled, const int channels) {
+  channels_enabled_ = enabled;
+  channels_ = channels;
+}
+
 bool GstEnginePipeline::InitFromUrl(const QByteArray &stream_url, const QUrl original_url, const qint64 end_nanosec) {
 
   stream_url_ = stream_url;
@@ -440,6 +447,10 @@ bool GstEnginePipeline::InitAudioBin() {
   gst_element_link(next, audioconverter);
 
   GstCaps *caps = gst_caps_new_empty_simple("audio/x-raw");
+  if (channels_enabled_ && channels_ > 0) {
+    qLog(Debug) << "Setting channels to" << channels_;
+    gst_caps_set_simple(caps, "channels", G_TYPE_INT, channels_, nullptr);
+  }
   gst_element_link_filtered(audioconverter, audiosink, caps);
   gst_caps_unref(caps);
 

src/engine/gstenginepipeline.h

@@ -74,6 +74,7 @@ class GstEnginePipeline : public QObject {
   void set_buffer_low_watermark(const double value);
   void set_buffer_high_watermark(const double value);
   void set_proxy_settings(const QString &address, const bool authentication, const QString &user, const QString &pass);
+  void set_channels(const bool enabled, const int channels);
 
   // Creates the pipeline, returns false on error
   bool InitFromUrl(const QByteArray &stream_url, const QUrl original_url, const qint64 end_nanosec);
@@ -221,6 +222,10 @@ class GstEnginePipeline : public QObject {
   QString proxy_user_;
   QString proxy_pass_;
 
+  // Channels
+  bool channels_enabled_;
+  int channels_;
+
   // These get called when there is a new audio buffer available
   QList<GstBufferConsumer*> buffer_consumers_;
   QMutex buffer_consumers_mutex_;