-#include <boost/enable_shared_from_this.hpp>
-#include "ffmpeg_content.h"
-#include "audio_mapping.h"
-
-class Content;
-class FFmpegContent;
-class FFmpegDecoder;
-class StillImageMagickContent;
-class StillImageMagickDecoder;
-class SndfileContent;
-class SndfileDecoder;
-class Job;
-class Film;
-class Region;