Optimisations and fixes

removed extra brace

Fix

settings.txt

@@ -122,6 +122,12 @@
 # Reduction level from 1 (no reduction) to 0 (fully silenced)
 #audio-fade = 0.3
 
+# Basic number of audio sample frames in the output buffer that is scaled by sample rate.
+# This controls the size of the audio buffer used by the audio device.
+# The buffer time is ~ 1/10 buffer size in ms, depending on sample rate e.g. 2048 = ~200ms 
+# Preferably use power of 2 for the values or check your audio driver documentation
+#audio-buffer-samples = 2048
+
 # Force application to use following audio driver as audio output, if empty use default driver
 # See SDL documentation for options. Some of them are
 # alsa - Not supporting multiple channels, navigation over music will not work

src/connector.cpp

@@ -32,7 +32,7 @@ Connector::~Connector()
     _active = false;
 
     if (_write_thread.joinable())
-        _write_thread.join();    
+        _write_thread.join();
 
     if (_cipher)
     {
@@ -154,7 +154,7 @@ bool Connector::nextState(u_int8_t state)
         _state = state;
         return true;
     }
-    
+
     if (state == PROTOCOL_STATUS_NO_DEVICE && (_nodeviceCount++ > 10 || _state >= PROTOCOL_STATUS_ONLINE))
     {
         _failCount = 0;
@@ -336,7 +336,7 @@ void Connector::readLoop()
 
         if (result != LIBUSB_SUCCESS || transferred != sizeof(Header))
         {
-            std::this_thread::sleep_for(std::chrono::milliseconds(10));
+            std::this_thread::sleep_for(std::chrono::milliseconds(1));
             continue;
         }
 
@@ -357,11 +357,15 @@ void Connector::readLoop()
             if (!_cipher)
             {
                 std::cout << "[Connection] Received encrypted command " << header.type << " but cipher is not initialised" << std::endl;
+                if (data)
+                    free(data);
                 continue;
             }
             if (!_cipher->Decrypt(data, header.length))
             {
                 std::cout << "[Connection] Can't decrypt command " << header.type << std::endl;
+                if (data)
+                    free(data);
                 continue;
             }
         }
@@ -383,7 +387,7 @@ void Connector::writeLoop()
 
     // Set thread name
     setThreadName("protocol-writer");
-    state(PROTOCOL_STATUS_LINKING);    
+    state(PROTOCOL_STATUS_LINKING);
 
     while (_active)
     {

src/main.cpp

@@ -23,6 +23,7 @@ extern "C"
 #include "pipe_listener.h"
 
 #define FRAME_DELAY_INACTIVE 200
+#define MAX_EVENTS_PER_FRAME 5
 
 static const char *title = "Fast Car Play v0.6";
 static SDL_Window *window = nullptr;
@@ -153,8 +154,9 @@ bool processEvents(Protocol &protocol, RunParams &params, Renderer &renderer)
     int downY = -1;
     int upX = -1;
     int upY = -1;
+    int processed = 0;
 
-    while (SDL_PollEvent(&e))
+    while (SDL_PollEvent(&e) && processed++ < MAX_EVENTS_PER_FRAME)
     {
         switch (e.type)
         {
@@ -268,6 +270,7 @@ void application()
     std::cout << "[Main] Loop" << std::endl;
     uint32_t latestid = 0;
     Uint32 frameStart = SDL_GetTicks();
+    uint32_t FrameRequest = 0;
     while (active)
     {
         if (processEvents(protocol, p, interface))
@@ -294,6 +297,17 @@ void application()
                     p.dirty = false;
                 }
                 videoBuffer.consume();
+                FrameRequest = 0;
+            }
+            else
+            {
+                if (Settings::forceRedraw)
+                {
+                    if (protocol.checkKey())
+                        FrameRequest = 3;
+                    else if (FrameRequest-- > 0)
+                        protocol.requestKeyframe();
+                }
             }
         }
 
@@ -303,16 +317,23 @@ void application()
             p.dirty = false;
         }
 
-        Uint32 frameEnd = SDL_GetTicks();
-        Uint32 frameTime = frameEnd - frameStart;
-        if (active && frameTime < p.frameDelay)
+        if (active)
         {
-            SDL_Delay(p.frameDelay - frameTime); // Sleep only the remaining time
-            frameStart = frameStart + p.frameDelay;
+            Uint32 frameEnd = SDL_GetTicks();
+            Uint32 frameTime = frameEnd - frameStart;
+            if (frameTime < p.frameDelay)
+            {
+                SDL_Delay(p.frameDelay - frameTime);
+                frameStart += p.frameDelay;
+            }
+            else
+            {
+                SDL_Delay(1);
+                frameStart += 1;
+            }
         }
-        else
-            frameStart = frameEnd;
     }
+
     std::cout << "[Main] Stopping" << std::endl;
     SDL_HideWindow(window);
 }
@@ -388,7 +409,7 @@ int start()
         return 1;
     }
 
-    if(!Settings::cursor)
+    if (!Settings::cursor)
         SDL_ShowCursor(SDL_DISABLE);
 
     // Create accelerated renderer for the window

src/pcm_audio.cpp

@@ -2,12 +2,13 @@
 #include "helper/functions.h"
 #include "settings.h"
 
+// Add sample size (buffer size in samples) to ChannelConfig
 ChannelConfig PcmAudio::_configTable[] = {
-    {8000, 1},  // type = 3
-    {48000, 2}, // type = 4
-    {16000, 1}, // type = 5
-    {24000, 1}, // type = 6
-    {16000, 2}, // type = 7
+    {8000, 1, 1},   // type = 3, ~256ms
+    {48000, 2, 4},  // type = 4, ~170ms
+    {16000, 1, 2},  // type = 5, ~256ms
+    {24000, 1, 2},  // type = 6, ~170ms
+    {16000, 2, 2},  // type = 7, ~256ms
 };
 
 // Implementation
@@ -139,7 +140,8 @@ ChannelConfig PcmAudio::getConfig(int type)
 {
     if (type >= 3 && type <= 7)
         return _configTable[type - 3];
-    return {44100, 2};
+    // Default: 44100Hz, stereo, 4096 samples
+    return {44100, 2, 4};
 }
 
 void PcmAudio::Fade(bool enable)
@@ -194,7 +196,7 @@ void PcmAudio::runner()
             spec.freq = config.rate;
             spec.format = AUDIO_S16SYS;
             spec.channels = config.channels;
-            spec.samples = 4096;
+            spec.samples = Settings::audioBuffer*config.scale;
             spec.callback = callback;
             spec.userdata = this;
 
@@ -202,7 +204,7 @@ void PcmAudio::runner()
             if (device == 0)
             {
                 std::cerr << _name << " Failed to open audio: " << SDL_GetError() << std::endl;
-                std::this_thread::sleep_for(std::chrono::milliseconds(100));
+                SDL_Delay(100);
                 continue;
             }
             _config = config;

src/pcm_audio.h

@@ -18,6 +18,7 @@ struct ChannelConfig
 {
     int rate;
     uint8_t channels;
+    uint8_t scale;
 
     bool operator==(ChannelConfig const &other) const
     {

src/protocol.cpp

@@ -15,6 +15,7 @@ Protocol::Protocol(uint16_t width, uint16_t height, uint16_t fps, uint16_t paddi
       _width(width),
       _height(height),
       _fps(fps),
+      _keySent(false),
       _phoneConnected(false)
 {
 }
@@ -113,18 +114,22 @@ void Protocol::sendConfig()
         sendInt(CMD_CONTROL, 1002);
 }
 
+bool Protocol::checkKey()
+{
+    bool result = _keySent;
+    _keySent = false;
+    return result;
+}
+
 void Protocol::sendKey(int key)
 {
-    uint8_t buf[4];
-    write_uint32_le(&buf[0], key);
+    sendInt(CMD_CONTROL, key, false);
+    _keySent = true;
+}
 
-    send(CMD_CONTROL, false, buf, 4);
-
-    if(Settings::forceRedraw)
-    {
-        write_uint32_le(&buf[0], BTN_SCREEN_REFRESH);
-        send(CMD_CONTROL, false, buf, 4);
-    }
+void Protocol::requestKeyframe()
+{
+    sendInt(CMD_CONTROL, BTN_SCREEN_REFRESH, false);
 }
 
 void Protocol::sendFile(const char *filename, const char *value)
@@ -323,7 +328,6 @@ void Protocol::onData(uint32_t cmd, uint32_t length, uint8_t *data)
             memcpy(&cmd, data, sizeof(int));
             onControl(cmd);
         }
-
         break;
 
     case CMD_PLUGGED:

src/protocol.h

@@ -22,7 +22,10 @@ public:
     void start(uint32_t evtStatus, uint32_t evtPhone);
     void stop();
 
+
+    bool checkKey();
     void sendKey(int key);
+    void requestKeyframe();
     void sendFile(const char *filename, const uint8_t *data, uint32_t length);
     void sendFile(const char *filename, const char *value);
     void sendFile(const char *filename, int value);
@@ -54,6 +57,7 @@ private:
     uint16_t _width;
     uint16_t _height;
     uint16_t _fps;
+    bool _keySent;
     bool _phoneConnected;
 
     uint32_t _evtStatusId = (uint32_t)-1;

src/renderer.cpp

@@ -174,7 +174,6 @@ bool Renderer::render(AVFrame *frame)
             return false;
     }
     (this->*_render)(frame);
-    SDL_RenderClear(_renderer);
     SDL_RenderCopy(_renderer, _texture, &_sourceRect, nullptr);
     SDL_RenderPresent(_renderer);
     return true;
@@ -250,9 +249,10 @@ bool Renderer::prepare(AVFrame *frame, int targetWidth, int targetHeight)
     if (!prepareTexture(SDL_PIXELFORMAT_IYUV, frame->width, frame->height))
         return false;
 
+    int swsFlags = Settings::fastScale ? SWS_FAST_BILINEAR : SWS_BILINEAR;
     _sws = sws_getContext(frame->width, frame->height, (AVPixelFormat)frame->format,
                           frame->width, frame->height, AV_PIX_FMT_YUV420P,
-                          SWS_BILINEAR, nullptr, nullptr, nullptr);
+                          swsFlags, nullptr, nullptr, nullptr);
     if (!_sws)
     {
         std::cerr << "[UX] Can't create sws context" << std::endl;

src/settings.h

@@ -43,6 +43,7 @@ public:
     static inline Setting<int> audioDelay{"audio-buffer-wait", 2};
     static inline Setting<int> audioDelayCall{"audio-buffer-wait-call", 8};
     static inline Setting<float> audioFade{"audio-fade", 0.3};
+    static inline Setting<int> audioBuffer{"audio-buffer-samples", 2048};    
     static inline Setting<std::string> audioDriver{"audio-driver", ""};
     static inline Setting<std::string> onConnect{"on-connect-script", ""};
     static inline Setting<std::string> onDisconnect{"on-disconnect-script", ""};