Method GetFrame

src/ChunkReader.cpp:184–242

Get an openshot::Frame object for a specific frame number of this reader.

// Get an openshot::Frame object for a specific frame number of this reader.
std::shared_ptr<Frame> ChunkReader::GetFrame(int64_t requested_frame)
{
	// Determine what chunk contains this frame
	ChunkLocation location = find_chunk_frame(requested_frame);

	// New Chunk (Close the old reader, and open the new one)
	if (previous_location.number != location.number)
	{
		// Determine version of chunk
		std::string folder_name = "";
		switch (version)
		{
		case THUMBNAIL:
			folder_name = "thumb";
			break;
		case PREVIEW:
			folder_name = "preview";
			break;
		case FINAL:
			folder_name = "final";
			break;
		}

		// Load path of chunk video
		std::string chunk_video_path = get_chunk_path(location.number, folder_name, ".webm");

		// Close existing reader (if needed)
		if (local_reader)
		{
			// Close and delete old reader
			local_reader->Close();
			delete local_reader;
		}

		try
		{
			// Load new FFmpegReader
			local_reader = new FFmpegReader(chunk_video_path);
			local_reader->Open(); // open reader

		} catch (const InvalidFile& e)
		{
			// Invalid Chunk (possibly it is not found)
			throw ChunkNotFound(path, requested_frame, location.number, location.frame);
		}

		// Set the new location
		previous_location = location;
	}

	// Get the frame (from the current reader)
	last_frame = local_reader->GetFrame(location.frame);

	// Update the frame number property
	last_frame->number = requested_frame;

	// Return the frame
	return last_frame;