Optimise queues and rendering

src/struct/video_buffer.h

@@ -1,5 +1,5 @@
-#ifndef SRC_VIDEO_BUFFER
-#define SRC_VIDEO_BUFFER
+#ifndef SRC_STRUCT_VIDEO_BUFFER
+#define SRC_STRUCT_VIDEO_BUFFER
 
 extern "C"
 {
@@ -7,31 +7,75 @@ extern "C"
 }
 
 #include <atomic>
-
-#include "helper/error.h"
+#include <stdexcept>
 
 #define BUFFER_VIDEO_FRAMES 3
 
 class VideoBuffer
 {
 public:
-    VideoBuffer();
-    ~VideoBuffer();
-    
-    Error allocate(uint16_t width, uint16_t height);
-    uint16_t width() const { return _width; };
-    uint16_t height() const { return _height; };
-    void reset();
-    bool getLatest(AVFrame **frame, uint32_t *id);
-    void consumeLatest();
-    const AVFrame *writeFrame(uint32_t id);
-    void commitFrame();
+    VideoBuffer()
+    {
+        _writing.store(0);
+        _reading.store(-1);
+        _latest.store(-1);
+        for (uint8_t i = 0; i < BUFFER_VIDEO_FRAMES; ++i)
+        {
+            _ids[i] = 0;
+            _frames[i] = av_frame_alloc();
+            if (!_frames[i])
+            {
+                throw std::runtime_error("Failed to allocate AVFrame");
+            }
+        }
+    }
+
+    ~VideoBuffer()
+    {
+        for (uint8_t i = 0; i < BUFFER_VIDEO_FRAMES; ++i)
+        {
+            if (_frames[i])
+            {
+                av_frame_free(&_frames[i]);
+                _frames[i] = nullptr;
+            }
+        }
+    }
+
+    bool latest(AVFrame **frame, uint32_t *id)
+    {
+        _reading.store(_latest.load());
+        int index = _reading.load();
+        if (index < 0)
+            return false;
+        *frame = _frames[index];
+        *id = _ids[index];
+        return true;
+    }
+
+    void consume()
+    {
+        _reading.store(-1);
+    }
+
+    AVFrame *write(uint32_t id)
+    {
+        int index = _writing.load();
+        while (index == _reading.load() || index == _latest.load())
+        {
+            index = (index + 1) % BUFFER_VIDEO_FRAMES;
+        }
+        _writing.store(index);
+        _ids[index] = id;
+        return _frames[index];
+    }
+
+    void commit()
+    {
+        _latest.store(_writing.load());
+    }
 
 private:
-    void deallocate();
-
-    uint16_t _width;
-    uint16_t _height;
     std::atomic<int8_t> _latest;
     std::atomic<int8_t> _reading;
     std::atomic<int8_t> _writing;
@@ -39,4 +83,4 @@ private:
     uint32_t _ids[BUFFER_VIDEO_FRAMES];
 };
 
-#endif /* SRC_VIDEO_BUFFER */
+#endif /* SRC_STRUCT_VIDEO_BUFFER */