- virtual ContentTime video_length () const = 0;
- virtual boost::optional<float> sample_aspect_ratio () const {
- return boost::optional<float> ();
+ /** @return video length in frames; must not be called if has_video() == false */
+ virtual Frame video_length () const = 0;
+ /** @return video sample aspect ratio (if known); must not be called if has_video() == false */
+ virtual boost::optional<double> sample_aspect_ratio () const {
+ return boost::optional<double> ();