+ ContentChangeSignaller cc (_parent, AudioContentProperty::STREAMS);
+
+ int c = 0;
+ for (auto i: streams()) {
+ AudioMapping stream_mapping (i->channels(), MAX_DCP_AUDIO_CHANNELS);
+ for (int j = 0; j < i->channels(); ++j) {
+ for (int k = 0; k < MAX_DCP_AUDIO_CHANNELS; ++k) {
+ stream_mapping.set (j, k, mapping.get(c, k));
+ }
+ ++c;
+ }
+ i->set_mapping (stream_mapping);
+ }
+}
+
+
+AudioMapping
+AudioContent::mapping () const
+{
+ int channels = 0;
+ for (auto i: streams()) {
+ channels += i->channels ();
+ }
+
+ AudioMapping merged (channels, MAX_DCP_AUDIO_CHANNELS);
+ merged.make_zero ();
+
+ int c = 0;
+ int s = 0;
+ for (auto i: streams()) {
+ auto mapping = i->mapping ();
+ for (int j = 0; j < mapping.input_channels(); ++j) {
+ for (int k = 0; k < MAX_DCP_AUDIO_CHANNELS; ++k) {
+ if (k < mapping.output_channels()) {
+ merged.set (c, k, mapping.get(j, k));
+ }
+ }
+ ++c;
+ }
+ ++s;
+ }
+
+ return merged;
+}
+
+
+/** @return the frame rate that this content should be resampled to in order
+ * that it is in sync with the active video content at its start time.
+ */
+int
+AudioContent::resampled_frame_rate (shared_ptr<const Film> film) const
+{
+ double t = film->audio_frame_rate ();
+
+ FrameRateChange frc (film, _parent);
+
+ /* Compensate if the DCP is being run at a different frame rate
+ to the source; that is, if the video is run such that it will
+ look different in the DCP compared to the source (slower or faster).
+ */
+
+ if (frc.change_speed) {
+ t /= frc.speed_up;
+ }
+
+ return lrint (t);
+}
+
+string
+AudioContent::processing_description (shared_ptr<const Film> film) const
+{
+ if (streams().empty()) {
+ return "";
+ }
+
+ /* Possible answers are:
+ 1. all audio will be resampled from x to y.
+ 2. all audio will be resampled to y (from a variety of rates)
+ 3. some audio will be resampled to y (from a variety of rates)
+ 4. nothing will be resampled.
+ */
+
+ bool not_resampled = false;
+ bool resampled = false;
+ bool same = true;
+
+ optional<int> common_frame_rate;
+ for (auto i: streams()) {
+ if (i->frame_rate() != resampled_frame_rate(film)) {
+ resampled = true;
+ } else {
+ not_resampled = true;
+ }
+
+ if (common_frame_rate && common_frame_rate != i->frame_rate ()) {
+ same = false;
+ }
+ common_frame_rate = i->frame_rate ();
+ }
+
+ if (not_resampled && !resampled) {
+ return _("Audio will not be resampled");
+ }
+
+ if (not_resampled && resampled) {
+ return String::compose (_("Some audio will be resampled to %1Hz"), resampled_frame_rate(film));