IReader: added behavior to generate data when there is no more data to decode

Clement Champetier · Clement Champetier · commit 61b9f6e300f1 · 2016-03-31T17:59:56.000+02:00
* New attribute: _continueWithGenerator
* New method: continueWithGenerator
diff --git a/src/AvTranscoder/reader/IReader.cpp b/src/AvTranscoder/reader/IReader.cpp
@@ -16,6 +16,7 @@ IReader::IReader(const std::string& filename, const size_t streamIndex, const in
     , _channelIndex(channelIndex)
     , _currentFrame(-1)
     , _inputFileAllocated(true)
+    , _continueWithGenerator(false)
 {
     _inputFile = new InputFile(filename);
 }
@@ -31,6 +32,7 @@ IReader::IReader(InputFile& inputFile, const size_t streamIndex, const int chann
     , _channelIndex(channelIndex)
     , _currentFrame(-1)
     , _inputFileAllocated(false)
+    , _continueWithGenerator(false)
 {
 }
 
@@ -53,6 +55,7 @@ Frame* IReader::readPrevFrame()
 Frame* IReader::readFrameAt(const size_t frame)
 {
     assert(_decoder != NULL);
+    assert(_generator != NULL);
     assert(_transform != NULL);
     assert(_srcFrame != NULL);
     assert(_dstFrame != NULL);
@@ -70,10 +73,20 @@ Frame* IReader::readFrameAt(const size_t frame)
         decodingStatus = _decoder->decodeNextFrame(*_srcFrame, _channelIndex);
     else
         decodingStatus = _decoder->decodeNextFrame(*_srcFrame);
+    // if decoding failed
     if(!decodingStatus)
     {
-        _dstFrame->clear();
-        return _dstFrame;
+        // generate data (ie silence or black)
+        if(_continueWithGenerator)
+        {
+           _generator->decodeNextFrame(*_srcFrame);
+        }
+        // or return an empty frame
+        else
+        {
+            _dstFrame->clear();
+            return _dstFrame;
+        }
     }
     // transform
     _transform->convert(*_srcFrame, *_dstFrame);
diff --git a/src/AvTranscoder/reader/IReader.hpp b/src/AvTranscoder/reader/IReader.hpp
@@ -53,10 +53,17 @@ class AvExport IReader
      */
     const StreamProperties* getSourceProperties() const { return _streamProperties; }
 
+    /**
+     * @brief Set the reader state to generate data (ie silence or black) when there is no more data to decode.
+     * @note By default, the reader returns an empty frame.
+     */
+    void continueWithGenerator(const bool continueWithGenerator = true) { _continueWithGenerator = continueWithGenerator; }
+
 protected:
     InputFile* _inputFile;
     const StreamProperties* _streamProperties;
     IDecoder* _decoder;
+    IDecoder* _generator;
 
     Frame* _srcFrame;
     Frame* _dstFrame;
@@ -69,6 +76,7 @@ class AvExport IReader
 private:
     int _currentFrame;        ///< The current decoded frame.
     bool _inputFileAllocated; ///< Does the InputFile is held by the class or not (depends on the constructor called)
+    bool _continueWithGenerator;  ///< If there is no more data to decode, complete with generated data
 };
 }
 
