Buffer management via scarcity

Rather than putting limits on the number of items in the buffers of individual processing stages of a stream, put a limit on the total number of frames actively being processed by the stream.

Buffer management via scarcity
Rather than putting limits on the number of items in the buffers of individual processing stages of a stream, put a limit on the total number of frames actively being processed by the stream.
Charles Otto
1 parent e9a774f1
Showing 1 changed file with 95 additions and 51 deletions
sdk/plugins/stream.cpp
@@ -29,7 +29,7 @@ public:
 class SharedBuffer
 {
 public:
-    SharedBuffer(int _maxItems = 200) : maxItems(_maxItems) {}
+    SharedBuffer(int _maxItems = 200000) : maxItems(_maxItems) {}
     virtual ~SharedBuffer() {}
  
     virtual void addItem(FrameData * input)=0;
@@ -49,7 +49,7 @@ protected:
 class SingleBuffer : public SharedBuffer
 {
 public:
-    SingleBuffer(unsigned _maxItems = 20) : SharedBuffer(_maxItems) { no_input = false; }
+    SingleBuffer(unsigned _maxItems = 20000) : SharedBuffer(_maxItems) { no_input = false; }
  
     void stoppedInput()
     {
@@ -119,40 +119,61 @@ private:
 class DataSource
 {
 public:
-    DataSource() {}
-    virtual ~DataSource() {}
+    DataSource(int maxFrames=100)
+    {
+        for (int i=0; i < maxFrames;i++)
+        {
+            allFrames.addItem(new FrameData());
+        }
+        allFrames.startInput();
+    }
+
+    virtual ~DataSource()
+    {
+        allFrames.stoppedInput();
+        while (true)
+        {
+            FrameData * frame = allFrames.getItem();
+            if (frame == NULL)
+                break;
+            delete frame;
+        }
+    }
+
+    FrameData * getFrame()
+    {
+        FrameData * aFrame = allFrames.getItem();
+        aFrame->data.clear();
+        aFrame->sequenceNumber = -1;
+
+        bool res = getNext(*aFrame);
+        if (!res) {
+            allFrames.addItem(aFrame);
+            return NULL;
+        }
+        return aFrame;
+    }
+
+    void returnFrame(FrameData * inputFrame)
+    {
+        allFrames.addItem(inputFrame);
+    }
  
-    virtual FrameData * getNext() = 0;
     virtual void close() = 0;
-    virtual bool open(Template & input) = 0;
+    virtual bool open(Template & output) = 0;
     virtual bool isOpen() = 0;
+
+    virtual bool getNext(FrameData & input) = 0;
+
+protected:
+    SingleBuffer allFrames;
 };
  
 // Read a video frame by frame using cv::VideoCapture
 class VideoDataSource : public DataSource
 {
 public:
-    VideoDataSource() {}
-
-    FrameData * getNext()
-    {
-        if (!isOpen())
-            return NULL;
-
-        FrameData * output = new FrameData();
-        output->data.append(Template(basis.file));
-        output->data.last().append(cv::Mat());
-
-        output->sequenceNumber = next_idx;
-        next_idx++;
-
-        bool res = video.read(output->data.last().last());
-        if (!res) {
-            delete output;
-            return NULL;
-        }
-        return output;
-    }
+    VideoDataSource(int maxFrames) : DataSource(maxFrames) {}
  
     bool open(Template &input)
     {
@@ -167,6 +188,24 @@ public:
     void close() { video.release(); }
  
 private:
+    bool getNext(FrameData & output)
+    {
+        if (!isOpen())
+            return false;
+
+        output.data.append(Template(basis.file));
+        output.data.last().append(cv::Mat());
+
+        output.sequenceNumber = next_idx;
+        next_idx++;
+
+        bool res = video.read(output.data.last().last());
+        if (!res) {
+            return false;
+        }
+        return true;
+    }
+
     cv::VideoCapture video;
     Template basis;
     int next_idx;
@@ -177,21 +216,9 @@ private:
 class TemplateDataSource : public DataSource
 {
 public:
-    TemplateDataSource() { current_idx = INT_MAX; }
-
-    FrameData * getNext()
+    TemplateDataSource(int maxFrames) : DataSource(maxFrames)
     {
-        if (!isOpen())
-            return NULL;
-
-        FrameData * output = new FrameData();
-        output->data.append(basis[current_idx]);
-        current_idx++;
-
-        output->sequenceNumber = next_sequence;
-        next_sequence++;
-
-        return output;
+        current_idx = INT_MAX;
     }
  
     bool open(Template &input)
@@ -211,6 +238,20 @@ public:
     }
  
 private:
+    bool getNext(FrameData & output)
+    {
+        if (!isOpen())
+            return false;
+
+        output.data.append(basis[current_idx]);
+        current_idx++;
+
+        output.sequenceNumber = next_sequence;
+        next_sequence++;
+
+        return true;
+    }
+
     Template basis;
     int current_idx;
     int next_sequence;
@@ -232,12 +273,6 @@ public:
         close();
     }
  
-    FrameData * getNext()
-    {
-        if (!isOpen()) return NULL;
-        return actualSource->getNext();
-    }
-
     void close()
     {
         if (actualSource) {
@@ -253,13 +288,13 @@ public:
         bool open_res = false;
         // Input has no matrices? Its probably a video that hasn't been loaded yet
         if (input.empty()) {
-            actualSource = new VideoDataSource();
+            actualSource = new VideoDataSource(0);
             open_res = actualSource->open(input);
             qDebug("created video resource status %d", open_res);
         }
         else {
             // create frame dealer
-            actualSource = new TemplateDataSource();
+            actualSource = new TemplateDataSource(0);
             open_res = actualSource->open(input);
         }
         if (!isOpen()) {
@@ -274,6 +309,11 @@ public:
  
 protected:
     DataSource * actualSource;
+    bool getNext(FrameData & output)
+    {
+        return actualSource->getNext(output);
+    }
+
 };
  
 class ProcessingStage : public QRunnable
@@ -347,7 +387,8 @@ public:
     {
         forever
         {
-            FrameData * aFrame = dataSource.getNext();
+            //FrameData * aFrame = dataSource.getNext();
+            FrameData * aFrame = dataSource.getFrame();
             if (aFrame == NULL)
                 break;
             outputBuffer->addItem(aFrame);
@@ -367,6 +408,7 @@ public:
 private:
     TemplateList collectedOutput;
 public:
+    DataSource * data;
     void run()
     {
         forever
@@ -377,7 +419,8 @@ public:
                 break;
             // Just put the item on collectedOutput
             collectedOutput.append(frame->data);
-            delete frame;
+            // Return the frame to the input frame buffer
+            data->returnFrame(frame);
         }
         this->markStop();
     }
@@ -505,6 +548,7 @@ public:
         }
  
         collectionStage.inputBuffer = sharedBuffers.last();
+        collectionStage.data = &readStage.dataSource;
         collectionStage.stage_id = next_stage_id;
     }