- virtual float video_frame_rate () const = 0;
- virtual libdcp::Size video_size () const = 0;
- virtual VideoFrame video_length () const = 0;
+ virtual boost::optional<double> video_frame_rate () const = 0;
+ virtual dcp::Size video_size () const = 0;
+ virtual Frame video_length () const = 0;
+ virtual boost::optional<double> sample_aspect_ratio () const {
+ return boost::optional<double> ();
+ }