X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Faudio_merger.h;h=226601e0ec61dffc92726bd8f98bbd976f21e9ad;hb=2d5b8cdde08044d323aa7193dfac6c9f8bca7131;hp=afb21871bd0c72f031acae149ff69eaa7aa11c23;hpb=bcb746a19d5cc5377eacb33b73b59549a7372487;p=dcpomatic.git

diff --git a/src/lib/audio_merger.h b/src/lib/audio_merger.h
index afb21871b..226601e0e 100644
--- a/src/lib/audio_merger.h
+++ b/src/lib/audio_merger.h
@@ -26,50 +26,51 @@ class AudioMerger
 public:
 	AudioMerger (int channels, boost::function<F (T)> t_to_f, boost::function<T (F)> f_to_t)
 		: _buffers (new AudioBuffers (channels, 0))
-		, _next_out (0)
+		, _last_pull (0)
 		, _t_to_f (t_to_f)
 		, _f_to_t (f_to_t)
 	{}
 
+	/** Pull audio up to a given time; after this call, no more data can be pushed
+	 *  before the specified time.
+	 */
 	TimedAudioBuffers<T>
-	push (boost::shared_ptr<const AudioBuffers> audio, T time)
+	pull (T time)
 	{
-		assert (time >= _next_out);
-
 		TimedAudioBuffers<T> out;
 		
-		if (time > _next_out) {
-			/* We can return some audio from our buffer; this is how many frames
-			   we are going to return.
-			*/
-			F const to_return = _t_to_f (time - _next_out);
-			out.audio.reset (new AudioBuffers (_buffers->channels(), to_return));
-			/* And this is how many we will get from our buffer */
-			F const to_return_from_buffers = min (to_return, _buffers->frames ());
-
-			/* Copy the data that we have to the back end of the return buffer */
-			out.audio->copy_from (_buffers.get(), to_return_from_buffers, 0, to_return - to_return_from_buffers);
-			/* Silence any gap at the start */
-			out.audio->make_silent (0, to_return - to_return_from_buffers);
+		F const to_return = _t_to_f (time - _last_pull);
+		out.audio.reset (new AudioBuffers (_buffers->channels(), to_return));
+		/* And this is how many we will get from our buffer */
+		F const to_return_from_buffers = min (to_return, _buffers->frames ());
+		
+		/* Copy the data that we have to the back end of the return buffer */
+		out.audio->copy_from (_buffers.get(), to_return_from_buffers, 0, to_return - to_return_from_buffers);
+		/* Silence any gap at the start */
+		out.audio->make_silent (0, to_return - to_return_from_buffers);
+		
+		out.time = _last_pull;
+		_last_pull = time;
+		
+		/* And remove the data we're returning from our buffers */
+		if (_buffers->frames() > to_return_from_buffers) {
+			_buffers->move (to_return_from_buffers, 0, _buffers->frames() - to_return_from_buffers);
+		}
+		_buffers->set_frames (_buffers->frames() - to_return_from_buffers);
 
-			out.time = _next_out;
-			_next_out += _f_to_t (to_return);
+		return out;
+	}
 
-			/* And remove the data we're returning from our buffers */
-			if (_buffers->frames() > to_return_from_buffers) {
-				_buffers->move (to_return_from_buffers, 0, _buffers->frames() - to_return_from_buffers);
-			}
-			_buffers->set_frames (_buffers->frames() - to_return_from_buffers);
-		}
+	void
+	push (boost::shared_ptr<const AudioBuffers> audio, T time)
+	{
+		assert (time >= _last_pull);
 
-		/* Now accumulate the new audio into our buffers */
 		F frame = _t_to_f (time);
-		F after = max (_buffers->frames(), frame + audio->frames() - _t_to_f (_next_out));
+		F after = max (_buffers->frames(), frame + audio->frames() - _t_to_f (_last_pull));
 		_buffers->ensure_size (after);
-		_buffers->accumulate_frames (audio.get(), 0, frame - _t_to_f (_next_out), audio->frames ());
+		_buffers->accumulate_frames (audio.get(), 0, frame - _t_to_f (_last_pull), audio->frames ());
 		_buffers->set_frames (after);
-
-		return out;
 	}
 
 	F min (F a, int b)
@@ -97,12 +98,12 @@ public:
 			return TimedAudioBuffers<T> ();
 		}
 		
-		return TimedAudioBuffers<T> (_buffers, _next_out);
+		return TimedAudioBuffers<T> (_buffers, _last_pull);
 	}
 	
 private:
 	boost::shared_ptr<AudioBuffers> _buffers;
-	T _next_out;
+	T _last_pull;
 	boost::function<F (T)> _t_to_f;
 	boost::function<T (F)> _f_to_t;
 };