Add and use dB/linear conversion functions.

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

diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index 63204dd6a8684fd50897e68dff0b6b8d15ea30c5..cfe762659ebdb6d91128557b35cccb3c08c56144 100644 (file)
--- a/src/lib/audio_buffers.cc
+++ b/src/lib/audio_buffers.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012-2017 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2020 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -18,6 +18,7 @@
 
 */
 
+#include "util.h"
 #include "audio_buffers.h"
 #include "dcpomatic_assert.h"
 #include <cassert>
@@ -52,6 +53,12 @@ AudioBuffers::AudioBuffers (boost::shared_ptr<const AudioBuffers> other)
        copy_from (other.get(), other->_frames, 0, 0);
 }
 
+AudioBuffers::AudioBuffers (boost::shared_ptr<const AudioBuffers> other, int32_t frames_to_copy, int32_t read_offset)
+{
+       allocate (other->_channels, frames_to_copy);
+       copy_from (other.get(), frames_to_copy, read_offset, 0);
+}
+
 AudioBuffers &
 AudioBuffers::operator= (AudioBuffers const & other)
 {
@@ -303,7 +310,7 @@ AudioBuffers::accumulate_frames (AudioBuffers const * from, int32_t frames, int3
 void
 AudioBuffers::apply_gain (float dB)
 {
-       float const linear = pow (10, dB / 20);
+       float const linear = db_to_linear (dB);
 
        for (int i = 0; i < _channels; ++i) {
                for (int j = 0; j < _frames; ++j) {