6 files changed, 58 insertions, 21 deletions

diff --git a/src/lib/analyse_audio_job.cc b/src/lib/analyse_audio_job.cc
index c863c6c68..6c142f5cf 100644
--- a/src/lib/analyse_audio_job.cc
+++ b/src/lib/analyse_audio_job.cc
@@ -74,7 +74,10 @@ AnalyseAudioJob::run ()
 	player->set_ignore_video ();
 	player->set_fast ();
 
-	int64_t const len = _playlist->length().frames_round (_film->audio_frame_rate());
+	DCPTime const start = _playlist->start().get_value_or (DCPTime ());
+	DCPTime const length = _playlist->length ();
+
+	Frame const len = DCPTime (length - start).frames_round (_film->audio_frame_rate());
 	_samples_per_point = max (int64_t (1), len / _num_points);
 
 	delete[] _current;
@@ -91,9 +94,9 @@ AnalyseAudioJob::run ()
 	if (has_any_audio) {
 		_done = 0;
 		DCPTime const block = DCPTime::from_seconds (1.0 / 8);
-		for (DCPTime t; t < _film->length(); t += block) {
+		for (DCPTime t = start; t < length; t += block) {
 			analyse (player->get_audio (t, block, false));
-			set_progress (t.seconds() / _film->length().seconds());
+			set_progress ((t.seconds() - start.seconds()) / (length.seconds() - start.seconds()));
 		}
 	}
 
diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index 0130f17b4..05b3d4a44 100644
--- a/src/lib/audio_buffers.cc
+++ b/src/lib/audio_buffers.cc
@@ -31,7 +31,7 @@ using boost::shared_ptr;
  *  @param channels Number of channels.
  *  @param frames Number of frames to reserve space for.
  */
-AudioBuffers::AudioBuffers (int channels, int frames)
+AudioBuffers::AudioBuffers (int channels, int32_t frames)
 {
 	allocate (channels, frames);
 }
@@ -72,7 +72,7 @@ AudioBuffers::~AudioBuffers ()
 }
 
 void
-AudioBuffers::allocate (int channels, int frames)
+AudioBuffers::allocate (int channels, int32_t frames)
 {
 	DCPOMATIC_ASSERT (frames >= 0);
 	DCPOMATIC_ASSERT (channels >= 0);
@@ -120,7 +120,7 @@ AudioBuffers::data (int c) const
  *  @param f Frames; must be less than or equal to the number of allocated frames.
  */
 void
-AudioBuffers::set_frames (int f)
+AudioBuffers::set_frames (int32_t f)
 {
 	DCPOMATIC_ASSERT (f <= _allocated_frames);
 
@@ -156,7 +156,7 @@ AudioBuffers::make_silent (int c)
 }
 
 void
-AudioBuffers::make_silent (int from, int frames)
+AudioBuffers::make_silent (int32_t from, int32_t frames)
 {
 	DCPOMATIC_ASSERT ((from + frames) <= _allocated_frames);
 
@@ -174,7 +174,7 @@ AudioBuffers::make_silent (int from, int frames)
  *  @param write_offset Offset to write to in `to'.
  */
 void
-AudioBuffers::copy_from (AudioBuffers const * from, int frames_to_copy, int read_offset, int write_offset)
+AudioBuffers::copy_from (AudioBuffers const * from, int32_t frames_to_copy, int32_t read_offset, int32_t write_offset)
 {
 	if (frames_to_copy == 0) {
 		/* Prevent the asserts from firing if there is nothing to do */
@@ -199,7 +199,7 @@ AudioBuffers::copy_from (AudioBuffers const * from, int frames_to_copy, int read
  */
 
 void
-AudioBuffers::move (int from, int to, int frames)
+AudioBuffers::move (int32_t from, int32_t to, int32_t frames)
 {
 	if (frames == 0) {
 		return;
@@ -241,12 +241,23 @@ AudioBuffers::accumulate_channel (AudioBuffers const * from, int from_channel, i
  *  the buffers, fill the new space with silence.
  */
 void
-AudioBuffers::ensure_size (int frames)
+AudioBuffers::ensure_size (int32_t frames)
 {
 	if (_allocated_frames >= frames) {
 		return;
 	}
 
+	/* Round up frames to the next power of 2 to reduce the number
+	   of realloc()s that are necessary.
+	*/
+	frames--;
+	frames |= frames >> 1;
+	frames |= frames >> 2;
+	frames |= frames >> 4;
+	frames |= frames >> 8;
+	frames |= frames >> 16;
+	frames++;
+
 	for (int i = 0; i < _channels; ++i) {
 		_data[i] = static_cast<float*> (realloc (_data[i], frames * sizeof (float)));
 		if (!_data[i]) {
@@ -261,7 +272,7 @@ AudioBuffers::ensure_size (int frames)
 }
 
 void
-AudioBuffers::accumulate_frames (AudioBuffers const * from, int read_offset, int write_offset, int frames)
+AudioBuffers::accumulate_frames (AudioBuffers const * from, int32_t read_offset, int32_t write_offset, int32_t frames)
 {
 	DCPOMATIC_ASSERT (_channels == from->channels ());
 	DCPOMATIC_ASSERT (read_offset >= 0);
diff --git a/src/lib/audio_buffers.h b/src/lib/audio_buffers.h
index bcf5d5928..122716d77 100644
--- a/src/lib/audio_buffers.h
+++ b/src/lib/audio_buffers.h
@@ -28,11 +28,15 @@
 
 /** @class AudioBuffers
  *  @brief A class to hold multi-channel audio data in float format.
+ *
+ *  The use of int32_t for frame counts in this class is due to the
+ *  round-up to the next power-of-2 code in ::ensure_size; if that
+ *  were changed the frame count could use any integer type.
  */
 class AudioBuffers
 {
 public:
-	AudioBuffers (int channels, int frames);
+	AudioBuffers (int channels, int32_t frames);
 	AudioBuffers (AudioBuffers const &);
 	AudioBuffers (boost::shared_ptr<const AudioBuffers>);
 	~AudioBuffers ();
@@ -42,7 +46,7 @@ public:
 	boost::shared_ptr<AudioBuffers> clone () const;
 	boost::shared_ptr<AudioBuffers> channel (int) const;
 
-	void ensure_size (int);
+	void ensure_size (int32_t);
 
 	float** data () const {
 		return _data;
@@ -58,30 +62,30 @@ public:
 		return _frames;
 	}
 
-	void set_frames (int f);
+	void set_frames (int32_t f);
 
 	void make_silent ();
 	void make_silent (int c);
-	void make_silent (int from, int frames);
+	void make_silent (int32_t from, int32_t frames);
 
 	void apply_gain (float);
 
-	void copy_from (AudioBuffers const * from, int frames_to_copy, int read_offset, int write_offset);
+	void copy_from (AudioBuffers const * from, int32_t frames_to_copy, int32_t read_offset, int32_t write_offset);
 	void copy_channel_from (AudioBuffers const * from, int from_channel, int to_channel);
-	void move (int from, int to, int frames);
+	void move (int32_t from, int32_t to, int32_t frames);
 	void accumulate_channel (AudioBuffers const * from, int from_channel, int to_channel, float gain = 1);
-	void accumulate_frames (AudioBuffers const *, int read_offset, int write_offset, int frames);
+	void accumulate_frames (AudioBuffers const *, int32_t read_offset, int32_t write_offset, int32_t frames);
 
 private:
-	void allocate (int, int);
+	void allocate (int channels, int32_t frames);
 	void deallocate ();
 
 	/** Number of channels */
 	int _channels;
 	/** Number of frames (where a frame is one sample across all channels) */
-	int _frames;
+	int32_t _frames;
 	/** Number of frames that _data can hold */
-	int _allocated_frames;
+	int32_t _allocated_frames;
 	/** Audio data (so that, e.g. _data[2][6] is channel 2, sample 6) */
 	float** _data;
 };
diff --git a/src/lib/film.cc b/src/lib/film.cc
index e48b08f3b..c89d96584 100644
--- a/src/lib/film.cc
+++ b/src/lib/film.cc
@@ -994,6 +994,7 @@ Film::move_content_later (shared_ptr<Content> c)
 	_playlist->move_later (c);
 }
 
+/** @return length of the film from time 0 to the last thing on the playlist */
 DCPTime
 Film::length () const
 {
diff --git a/src/lib/playlist.cc b/src/lib/playlist.cc
index a1b209a11..4aff1015d 100644
--- a/src/lib/playlist.cc
+++ b/src/lib/playlist.cc
@@ -263,6 +263,7 @@ Playlist::best_dcp_frame_rate () const
 	return best->dcp;
 }
 
+/** @return length of the playlist from time 0 to the last thing on the playlist */
 DCPTime
 Playlist::length () const
 {
@@ -274,6 +275,22 @@ Playlist::length () const
 	return len;
 }
 
+/** @return position of the first thing on the playlist, if it's not empty */
+optional<DCPTime>
+Playlist::start () const
+{
+	if (_content.empty ()) {
+		return optional<DCPTime> ();
+	}
+
+	DCPTime start = DCPTime::max ();
+	BOOST_FOREACH (shared_ptr<Content> i, _content) {
+		start = min (start, i->position ());
+	}
+
+	return start;
+}
+
 void
 Playlist::reconnect ()
 {
diff --git a/src/lib/playlist.h b/src/lib/playlist.h
index d9c035ac7..76055bea0 100644
--- a/src/lib/playlist.h
+++ b/src/lib/playlist.h
@@ -58,6 +58,7 @@ public:
 	std::string video_identifier () const;
 
 	DCPTime length () const;
+	boost::optional<DCPTime> start () const;
 
 	int best_dcp_frame_rate () const;
 	DCPTime video_end () const;