Add gain variable to accumulate_channel.

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

diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index e80142b8e518ad2efe66f5f1c1ee4b90f6dcafa6..a1c9b81ac099259bbe86e2f9f8dcea1340bbb9ae 100644 (file)
--- a/src/lib/audio_buffers.cc
+++ b/src/lib/audio_buffers.cc
@@ -210,9 +210,11 @@ AudioBuffers::move (int from, int to, int frames)
        }
 }
 
-/** 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);
@@ -222,7 +224,7 @@ 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;
        }
 }