+ optional<ContentTime> pos;
+ shared_ptr<const Film> f = film();
+
+ if (video && !video->ignore() && (!pos || video->position(f) < *pos)) {
+ pos = video->position(f);
+ }
+
+ if (audio && !audio->ignore() && (!pos || audio->position(f) < *pos)) {
+ pos = audio->position(f);
+ }