initial chunck readers/writers

src/ChunkWriter.cpp

@@ -0,0 +1,152 @@
+/**
+ * \file
+ * \brief Source code for the ChunkWriter class
+ * \author Copyright (c) 2013 Jonathan Thomas
+ */
+
+
+#include "../include/ChunkWriter.h"
+
+using namespace openshot;
+
+ChunkWriter::ChunkWriter(FileReaderBase *reader, string path) throw (InvalidFile, InvalidFormat, InvalidCodec, InvalidOptions, OutOfMemory) :
+		path(path), cache_size(8), is_writing(false)
+{
+	// Init FileInfo struct (clear all values)
+	InitFileInfo();
+
+	// Copy info struct from the source reader
+	CopyReaderInfo(reader);
+}
+
+// Add a frame to the queue waiting to be encoded.
+void ChunkWriter::WriteFrame(tr1::shared_ptr<Frame> frame)
+{
+	// Add frame pointer to "queue", waiting to be processed the next
+	// time the WriteFrames() method is called.
+	spooled_frames.push_back(frame);
+
+	// Write the frames once it reaches the correct cache size
+	if (spooled_frames.size() == cache_size)
+	{
+		// Is writer currently writing?
+		if (!is_writing)
+			// Write frames to video file
+			write_queued_frames();
+
+		else
+		{
+			// YES, WRITING... so wait until it finishes, before writing again
+			while (is_writing)
+				Sleep(1); // sleep for 250 milliseconds
+
+			// Write frames to video file
+			write_queued_frames();
+		}
+	}
+
+	// Keep track of the last frame added
+	last_frame = frame;
+}
+
+// Write all frames in the queue to the video file.
+void ChunkWriter::write_queued_frames()
+{
+	// Flip writing flag
+	is_writing = true;
+
+	// Transfer spool to queue
+	queued_frames = spooled_frames;
+
+	// Empty spool
+	spooled_frames.clear();
+
+	//omp_set_num_threads(1);
+	omp_set_nested(true);
+	#pragma omp parallel
+	{
+		#pragma omp single
+		{
+			// Loop through each queued image frame
+			while (!queued_frames.empty())
+			{
+				// Get front frame (from the queue)
+				tr1::shared_ptr<Frame> frame = queued_frames.front();
+
+				// Add to processed queue
+				processed_frames.push_back(frame);
+
+				// Encode and add the frame to the output file
+				process_frame(frame);
+
+				// Remove front item
+				queued_frames.pop_front();
+
+			} // end while
+
+			// Done writing
+			is_writing = false;
+
+		} // end omp single
+	} // end omp parallel
+
+}
+
+// Write a block of frames from a reader
+void ChunkWriter::WriteFrame(FileReaderBase* reader, int start, int length)
+{
+	// Loop through each frame (and encoded it)
+	for (int number = start; number <= length; number++)
+	{
+		// Get the frame
+		tr1::shared_ptr<Frame> f = reader->GetFrame(number);
+
+		// Encode frame
+		WriteFrame(f);
+	}
+}
+
+// Close the writer
+void ChunkWriter::Close()
+{
+	// Reset frame counters
+	write_video_count = 0;
+	write_audio_count = 0;
+}
+
+// process frame
+void ChunkWriter::process_frame(tr1::shared_ptr<Frame> frame)
+{
+	#pragma omp task firstprivate(frame)
+	{
+		// Determine the height & width of the source image
+		int source_image_width = frame->GetWidth();
+		int source_image_height = frame->GetHeight();
+
+		// Generate frame image name
+		stringstream thumb_name;
+		stringstream preview_name;
+		stringstream final_name;
+		thumb_name << frame->number << "_t.JPG";
+		preview_name << frame->number << "_p.JPG";
+		final_name << frame->number << "_f.JPG";
+
+		#pragma omp critical (chunk_output)
+		cout << "Writing " << thumb_name.str() << endl;
+
+		// Do nothing if size is 1x1 (i.e. no image in this frame)
+		if (source_image_height > 1 && source_image_width > 1)
+		{
+			// Write image of frame to chunk
+			frame->Save(thumb_name.str(), 0.25);
+			frame->Save(preview_name.str(), 0.5);
+			frame->Save(final_name.str(), 1.0);
+		}
+
+
+
+	} // end task
+
+}
+
+