Merge master.

[dcpomatic.git] / src / lib / audio_content.cc

diff --git a/src/lib/audio_content.cc b/src/lib/audio_content.cc
index b4c4f34b6f064aaa71e822869728e266c488bdf0..3c0d13ba93c1b98b5bbd1760f33ecc16c38786db 100644 (file)
--- a/src/lib/audio_content.cc
+++ b/src/lib/audio_content.cc
@@ -40,7 +40,7 @@ int const AudioContentProperty::AUDIO_GAIN = 203;
 int const AudioContentProperty::AUDIO_DELAY = 204;
 int const AudioContentProperty::AUDIO_MAPPING = 205;
 
-AudioContent::AudioContent (shared_ptr<const Film> f, Time s)
+AudioContent::AudioContent (shared_ptr<const Film> f, DCPTime s)
        : Content (f, s)
        , _audio_gain (0)
        , _audio_delay (Config::instance()->default_audio_delay ())
@@ -149,3 +149,27 @@ AudioContent::technical_summary () const
 {
        return String::compose ("audio: channels %1, length %2, raw rate %3, out rate %4", audio_channels(), audio_length(), content_audio_frame_rate(), output_audio_frame_rate());
 }
+
+/** Note: this is not particularly fast, as the FrameRateChange lookup
+ *  is not very intelligent.
+ *
+ *  @param t Some duration to convert.
+ *  @param at The time within the DCP to get the active frame rate change from; i.e. a point at which
+ *  the `controlling' video content is active.
+ */
+AudioFrame
+AudioContent::time_to_content_audio_frames (DCPTime t, DCPTime at) const
+{
+       shared_ptr<const Film> film = _film.lock ();
+       assert (film);
+       
+       /* Consider the case where we're running a 25fps video at 24fps (i.e. slow)
+          Our audio is at 44.1kHz.  We will resample it to 48000 * 25 / 24 and then
+          run it at 48kHz (i.e. slow, to match).
+
+          After 1 second, we'll have run the equivalent of 44.1kHz * 24 / 25 samples
+          in the source.
+       */
+       
+       return rint (t * content_audio_frame_rate() * film->active_frame_rate_change(at).speed_up / TIME_HZ);
+}