+public:
+ FrameRateCandidate (float source_, int dcp_)
+ : source (source_)
+ , dcp (dcp_)
+ {}
+
+ float source;
+ int dcp;
+};
+
+int
+Playlist::best_dcp_frame_rate () const
+{
+ list<int> const allowed_dcp_frame_rates = Config::instance()->allowed_dcp_frame_rates ();
+
+ /* Work out what rates we could manage, including those achieved by using skip / repeat. */
+ list<FrameRateCandidate> candidates;
+
+ /* Start with the ones without skip / repeat so they will get matched in preference to skipped/repeated ones */
+ for (list<int>::const_iterator i = allowed_dcp_frame_rates.begin(); i != allowed_dcp_frame_rates.end(); ++i) {
+ candidates.push_back (FrameRateCandidate (*i, *i));
+ }
+
+ /* Then the skip/repeat ones */
+ for (list<int>::const_iterator i = allowed_dcp_frame_rates.begin(); i != allowed_dcp_frame_rates.end(); ++i) {
+ candidates.push_back (FrameRateCandidate (float (*i) / 2, *i));
+ candidates.push_back (FrameRateCandidate (float (*i) * 2, *i));
+ }
+
+ /* Pick the best one */
+ float error = std::numeric_limits<float>::max ();
+ optional<FrameRateCandidate> best;
+ list<FrameRateCandidate>::iterator i = candidates.begin();
+ while (i != candidates.end()) {
+
+ float this_error = 0;
+ for (ContentList::const_iterator j = _content.begin(); j != _content.end(); ++j) {
+ shared_ptr<VideoContent> vc = dynamic_pointer_cast<VideoContent> (*j);
+ if (!vc) {
+ continue;
+ }
+
+ /* Use the largest difference between DCP and source as the "error" */
+ this_error = max (this_error, float (fabs (i->source - vc->video_frame_rate ())));
+ }
+
+ if (this_error < error) {
+ error = this_error;
+ best = *i;
+ }
+
+ ++i;
+ }
+
+ if (!best) {
+ return 24;