feat(audio): allow sending continuous audio (#4261)

src/audio.cpp

@@ -193,7 +193,8 @@ namespace audio {
     }
 
     auto frame_size = config.packetDuration * stream.sampleRate / 1000;
-    auto mic = control->microphone(stream.mapping, stream.channelCount, stream.sampleRate, frame_size);
+    bool continuous_audio = config.flags[config_t::CONTINUOUS_AUDIO];
+    auto mic = control->microphone(stream.mapping, stream.channelCount, stream.sampleRate, frame_size, continuous_audio);
     if (!mic) {
       return;
     }
@@ -230,7 +231,7 @@ namespace audio {
           BOOST_LOG(info) << "Reinitializing audio capture"sv;
           mic.reset();
           do {
-            mic = control->microphone(stream.mapping, stream.channelCount, stream.sampleRate, frame_size);
+            mic = control->microphone(stream.mapping, stream.channelCount, stream.sampleRate, frame_size, continuous_audio);
             if (!mic) {
               BOOST_LOG(warning) << "Couldn't re-initialize audio input"sv;
             }

src/audio.h

@@ -45,6 +45,7 @@ namespace audio {
       HIGH_QUALITY,  ///< High quality audio
       HOST_AUDIO,  ///< Host audio
       CUSTOM_SURROUND_PARAMS,  ///< Custom surround parameters
+      CONTINUOUS_AUDIO,  ///< Continuous audio
       MAX_FLAGS  ///< Maximum number of flags
     };
 

src/nvhttp.cpp

@@ -307,6 +307,7 @@ namespace nvhttp {
     launch_session->enable_sops = util::from_view(get_arg(args, "sops", "0"));
     launch_session->surround_info = util::from_view(get_arg(args, "surroundAudioInfo", "196610"));
     launch_session->surround_params = (get_arg(args, "surroundParams", ""));
+    launch_session->continuous_audio = util::from_view(get_arg(args, "continuousAudio", "0"));
     launch_session->gcmap = util::from_view(get_arg(args, "gcmap", "0"));
     launch_session->enable_hdr = util::from_view(get_arg(args, "hdrMode", "0"));
 

src/platform/common.h

@@ -554,7 +554,7 @@ namespace platf {
   public:
     virtual int set_sink(const std::string &sink) = 0;
 
-    virtual std::unique_ptr<mic_t> microphone(const std::uint8_t *mapping, int channels, std::uint32_t sample_rate, std::uint32_t frame_size) = 0;
+    virtual std::unique_ptr<mic_t> microphone(const std::uint8_t *mapping, int channels, std::uint32_t sample_rate, std::uint32_t frame_size, bool continuous) = 0;
 
     /**
      * @brief Check if the audio sink is available in the system.

src/platform/linux/audio.cpp

@@ -440,7 +440,7 @@ namespace platf {
         return monitor_name;
       }
 
-      std::unique_ptr<mic_t> microphone(const std::uint8_t *mapping, int channels, std::uint32_t sample_rate, std::uint32_t frame_size) override {
+      std::unique_ptr<mic_t> microphone(const std::uint8_t *mapping, int channels, std::uint32_t sample_rate, std::uint32_t frame_size, bool continuous_audio) override {
         // Sink choice priority:
         // 1. Config sink
         // 2. Last sink swapped to (Usually virtual in this case)

src/platform/macos/microphone.mm

@@ -49,7 +49,7 @@ namespace platf {
       return 0;
     }
 
-    std::unique_ptr<mic_t> microphone(const std::uint8_t *mapping, int channels, std::uint32_t sample_rate, std::uint32_t frame_size) override {
+    std::unique_ptr<mic_t> microphone(const std::uint8_t *mapping, int channels, std::uint32_t sample_rate, std::uint32_t frame_size, bool continuous_audio) override {
       auto mic = std::make_unique<av_mic_t>();
       const char *audio_sink = "";
 

src/platform/windows/audio.cpp

@@ -432,7 +432,11 @@ namespace platf::audio {
       // Refill the sample buffer if needed
       while (sample_buf_pos - std::begin(sample_buf) < sample_size) {
         auto capture_result = _fill_buffer();
-        if (capture_result != capture_e::ok) {
+        if (capture_result == capture_e::timeout && continuous_audio) {
+          // Write silence to sample_buf
+          std::fill_n(sample_buf_pos, sample_size, 0.0f);
+          sample_buf_pos += sample_size;
+        } else if (capture_result != capture_e::ok) {
           return capture_result;
         }
       }
@@ -447,7 +451,7 @@ namespace platf::audio {
       return capture_e::ok;
     }
 
-    int init(std::uint32_t sample_rate, std::uint32_t frame_size, std::uint32_t channels_out) {
+    int init(std::uint32_t sample_rate, std::uint32_t frame_size, std::uint32_t channels_out, bool continuous) {
       audio_event.reset(CreateEventA(nullptr, FALSE, FALSE, nullptr));
       if (!audio_event) {
         BOOST_LOG(error) << "Couldn't create Event handle"sv;
@@ -508,6 +512,7 @@ namespace platf::audio {
       REFERENCE_TIME default_latency;
       audio_client->GetDevicePeriod(&default_latency, nullptr);
       default_latency_ms = default_latency / 1000;
+      continuous_audio = continuous;
 
       std::uint32_t frames;
       status = audio_client->GetBufferSize(&frames);
@@ -678,6 +683,7 @@ namespace platf::audio {
     util::buffer_t<float> sample_buf;
     float *sample_buf_pos;
     int channels;
+    bool continuous_audio;
 
     HANDLE mmcss_task_handle = nullptr;
   };
@@ -761,10 +767,10 @@ namespace platf::audio {
       return std::nullopt;
     }
 
-    std::unique_ptr<mic_t> microphone(const std::uint8_t *mapping, int channels, std::uint32_t sample_rate, std::uint32_t frame_size) override {
+    std::unique_ptr<mic_t> microphone(const std::uint8_t *mapping, int channels, std::uint32_t sample_rate, std::uint32_t frame_size, bool continuous_audio) override {
       auto mic = std::make_unique<mic_wasapi_t>();
 
-      if (mic->init(sample_rate, frame_size, channels)) {
+      if (mic->init(sample_rate, frame_size, channels, continuous_audio)) {
         return nullptr;
       }
 

src/rtsp.cpp

@@ -1030,6 +1030,10 @@ namespace rtsp_stream {
       }
       config.audio.flags[audio::config_t::CUSTOM_SURROUND_PARAMS] = valid;
     }
+    if (session.continuous_audio) {
+      BOOST_LOG(info) << "Client requested continuous audio"sv;
+      config.audio.flags[audio::config_t::CONTINUOUS_AUDIO] = true;
+    }
 
     // If the client sent a configured bitrate, we will choose the actual bitrate ourselves
     // by using FEC percentage and audio quality settings. If the calculated bitrate ends up

src/rtsp.h

@@ -32,6 +32,7 @@ namespace rtsp_stream {
     int appid;
     int surround_info;
     std::string surround_params;
+    bool continuous_audio;
     bool enable_hdr;
     bool enable_sops;
 

tests/unit/test_audio.cpp

@@ -19,7 +19,7 @@ struct AudioTest: PlatformTestSuite, testing::WithParamInterface<std::tuple<std:
 };
 
 constexpr std::bitset<config_t::MAX_FLAGS> config_flags(const int flag = -1) {
-  std::bitset<3> result = std::bitset<config_t::MAX_FLAGS>();
+  auto result = std::bitset<config_t::MAX_FLAGS>();
   if (flag >= 0) {
     result.set(flag);
   }