Add support for PulseAudio properties

README.md

@@ -116,7 +116,7 @@ Available audio backends are configured using the `--player` command line parame
 | Backend   | OS      | Description  | Parameters |
 | --------- | ------- | ------------ | ---------- |
 | alsa      | Linux   | ALSA | `buffer_time=<total buffer size [ms]>` (default 80, min 10)<br />`fragments=<number of buffers>` (default 4, min 2) |
-| pulse     | Linux   | PulseAudio | `buffer_time=<buffer size [ms]>` (default 100, min 10)<br />`server=<PulseAudio server>` - default not-set: use the default server |
+| pulse     | Linux   | PulseAudio | `buffer_time=<buffer size [ms]>` (default 100, min 10)<br />`server=<PulseAudio server>` - default not-set: use the default server<br />`property=<key>=<value>` set PA property, can be used multiple times (default `media.role=music`)  |
 | oboe      | Android | Oboe, using OpenSL ES on Android 4.1 and AAudio on 8.1 | |
 | opensl    | Android | OpenSL ES | |
 | coreaudio | macOS   | Core Audio | |

client/player/pulse_player.cpp

@@ -19,6 +19,8 @@
 #include <cassert>
 #include <iostream>
 
+#include <pulse/proplist.h>
+
 #include "common/aixlog.hpp"
 #include "common/snap_exception.hpp"
 #include "common/str_compat.hpp"
@@ -133,13 +135,30 @@ vector<PcmDevice> PulsePlayer::pcm_list(const std::string& parameter)
 
 
 PulsePlayer::PulsePlayer(boost::asio::io_context& io_context, const ClientSettings::Player& settings, std::shared_ptr<Stream> stream)
-    : Player(io_context, settings, stream), latency_(BUFFER_TIME), pa_ml_(nullptr), pa_ctx_(nullptr), playstream_(nullptr), server_(boost::none)
+    : Player(io_context, settings, stream), latency_(BUFFER_TIME), pa_ml_(nullptr), pa_ctx_(nullptr), playstream_(nullptr), proplist_(nullptr),
+      server_(boost::none)
 {
-    auto params = utils::string::split_pairs(settings.parameter, ',', '=');
+    auto params = utils::string::split_pairs_to_container<std::vector<std::string>>(settings.parameter, ',', '=');
     if (params.find("buffer_time") != params.end())
-        latency_ = std::chrono::milliseconds(std::max(cpt::stoi(params["buffer_time"]), 10));
+        latency_ = std::chrono::milliseconds(std::max(cpt::stoi(params["buffer_time"].front()), 10));
     if (params.find("server") != params.end())
-        server_ = params["server"];
+        server_ = params["server"].front();
+    properties_[PA_PROP_MEDIA_ROLE] = "music";
+    if (params.find("property") != params.end())
+    {
+        for (const auto& p : params["property"])
+        {
+            std::string value;
+            std::string key = utils::string::split_left(p, '=', value);
+            if (!key.empty())
+                properties_[key] = value;
+        }
+    }
+    for (const auto& property : properties_)
+    {
+        if (!property.second.empty())
+            LOG(INFO, LOG_TAG) << "Setting property \"" << property.first << "\" to \"" << property.second << "\"\n";
+    }
 
     LOG(INFO, LOG_TAG) << "Using buffer_time: " << latency_.count() / 1000 << " ms, server: " << server_.value_or("default") << "\n";
 }
@@ -337,7 +356,15 @@ void PulsePlayer::start()
     pa_ready_ = 0;
     pa_ml_ = pa_mainloop_new();
     pa_mainloop_api* pa_mlapi = pa_mainloop_get_api(pa_ml_);
-    pa_ctx_ = pa_context_new(pa_mlapi, "Snapcast");
+
+    proplist_ = pa_proplist_new();
+    for (const auto& property : properties_)
+    {
+        if (!property.second.empty())
+            pa_proplist_sets(proplist_, property.first.c_str(), property.second.c_str());
+    }
+
+    pa_ctx_ = pa_context_new_with_proplist(pa_mlapi, "Snapcast", proplist_);
 
     const char* server = server_.has_value() ? server_.value().c_str() : nullptr;
     if (pa_context_connect(pa_ctx_, server, PA_CONTEXT_NOFLAGS, nullptr) < 0)
@@ -476,6 +503,12 @@ void PulsePlayer::stop()
         pa_stream_unref(playstream_);
         playstream_ = nullptr;
     }
+
+    if (proplist_ != nullptr)
+    {
+        pa_proplist_free(proplist_);
+        proplist_ = nullptr;
+    }
 }
 
 } // namespace player

client/player/pulse_player.hpp

@@ -73,7 +73,9 @@ protected:
     pa_mainloop* pa_ml_;
     pa_context* pa_ctx_;
     pa_stream* playstream_;
+    pa_proplist* proplist_;
     boost::optional<std::string> server_;
+    std::map<std::string, std::string> properties_;
 
     // cache of the last volume change
     std::chrono::time_point<std::chrono::steady_clock> last_change_;

client/snapclient.cpp

@@ -363,7 +363,8 @@ int main(int argc, char** argv)
             {
                 cout << "Options are a comma separated list of:\n"
                      << " \"buffer_time=<buffer size [ms]>\" - default 100, min 10\n"
-                     << " \"server=<PulseAudio server>\" - default not-set: use the default server\n";
+                     << " \"server=<PulseAudio server>\" - default not-set: use the default server\n"
+                     << " \"property=<key>=<value>\" - can be set multiple times, default 'media.role=music'\n";
             }
 #endif
 #ifdef HAS_ALSA

common/utils/string_utils.hpp

@@ -143,10 +143,10 @@ static std::vector<std::string> split(const std::string& s, char delim)
     return elems;
 }
 
-
+template <typename T>
-static std::map<std::string, std::string> split_pairs(const std::string& s, char pair_delim, char key_value_delim)
+static std::map<std::string, T> split_pairs_to_container(const std::string& s, char pair_delim, char key_value_delim)
 {
-    std::map<std::string, std::string> result;
+    std::map<std::string, T> result;
     auto keyValueList = split(s, pair_delim);
     for (auto& kv : keyValueList)
     {
@@ -155,13 +155,23 @@ static std::map<std::string, std::string> split_pairs(const std::string& s, char
         {
             std::string key = trim_copy(kv.substr(0, pos));
             std::string value = trim_copy(kv.substr(pos + 1));
-            result[key] = value;
+            result[key].push_back(std::move(value));
         }
     }
     return result;
 }
 
 
+static std::map<std::string, std::string> split_pairs(const std::string& s, char pair_delim, char key_value_delim)
+{
+    std::map<std::string, std::string> result;
+    auto pairs = split_pairs_to_container<std::vector<std::string>>(s, pair_delim, key_value_delim);
+    for (auto& pair : pairs)
+        result[pair.first] = *pair.second.begin();
+    return result;
+}
+
+
 } // namespace string
 } // namespace utils