X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Faudio_buffers.cc;h=8d00fa8ba5a2bec7d0d5894cc1ea730d4beedb21;hb=8c11b87490f0e0e75487c856b4f8584472376d26;hp=d387304142462c6245b70aace709c730deb669ae;hpb=e16c8ed02a0cb1f733a990d75a9de1bf50cf89bd;p=dcpomatic.git

diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index d38730414..8d00fa8ba 100644
--- a/src/lib/audio_buffers.cc
+++ b/src/lib/audio_buffers.cc
@@ -19,6 +19,7 @@
 
 #include <cassert>
 #include <cstring>
+#include <cmath>
 #include <stdexcept>
 #include "audio_buffers.h"
 
@@ -43,9 +44,6 @@ AudioBuffers::AudioBuffers (AudioBuffers const & other)
 	copy_from (&other, other._frames, 0, 0);
 }
 
-/* XXX: it's a shame that this is a copy-and-paste of the above;
-   probably fixable with c++0x.
-*/
 AudioBuffers::AudioBuffers (boost::shared_ptr<const AudioBuffers> other)
 {
 	allocate (other->_channels, other->_frames);
@@ -75,6 +73,9 @@ AudioBuffers::~AudioBuffers ()
 void
 AudioBuffers::allocate (int channels, int frames)
 {
+	assert (frames >= 0);
+	assert (channels >= 0);
+
 	_channels = channels;
 	_frames = frames;
 	_allocated_frames = frames;
@@ -113,13 +114,21 @@ AudioBuffers::data (int c) const
 }
 
 /** Set the number of frames that these AudioBuffers will report themselves
- *  as having.
+ *  as having.  If we reduce the number of frames, the `lost' frames will
+ *  be silenced.
  *  @param f Frames; must be less than or equal to the number of allocated frames.
  */
 void
 AudioBuffers::set_frames (int f)
 {
 	assert (f <= _allocated_frames);
+
+	for (int c = 0; c < _channels; ++c) {
+		for (int i = f; i < _frames; ++i) {
+			_data[c][i] = 0;
+		}
+	}
+	
 	_frames = f;
 }
 
@@ -197,16 +206,18 @@ AudioBuffers::move (int from, int to, int frames)
 	assert (frames > 0);
 	assert (frames <= _frames);
 	assert ((from + frames) <= _frames);
-	assert ((to + frames) <= _frames);
+	assert ((to + frames) <= _allocated_frames);
 	
 	for (int i = 0; i < _channels; ++i) {
 		memmove (_data[i] + to, _data[i] + from, frames * sizeof(float));
 	}
 }
 
-/** Add data from from `from', `from_channel' to our channel `to_channel' */
+/** Add data from from `from', `from_channel' to our channel `to_channel'.
+ *  @param gain Linear gain to apply to the data before it is added.
+ */
 void
-AudioBuffers::accumulate_channel (AudioBuffers const * from, int from_channel, int to_channel)
+AudioBuffers::accumulate_channel (AudioBuffers const * from, int from_channel, int to_channel, float gain)
 {
 	int const N = frames ();
 	assert (from->frames() == N);
@@ -216,7 +227,7 @@ AudioBuffers::accumulate_channel (AudioBuffers const * from, int from_channel, i
 	float* d = _data[to_channel];
 
 	for (int i = 0; i < N; ++i) {
-		*d++ += *s++;
+		*d++ += (*s++) * gain;
 	}
 }
 
@@ -255,3 +266,15 @@ AudioBuffers::accumulate_frames (AudioBuffers const * from, int read_offset, int
 	}
 }
 
+/** @param dB gain in dB */
+void
+AudioBuffers::apply_gain (float dB)
+{
+	float const linear = pow (10, dB / 20);
+	
+	for (int i = 0; i < _channels; ++i) {
+		for (int j = 0; j < _frames; ++j) {
+			_data[i][j] *= linear;
+		}
+	}
+}