X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Faudio_buffers.cc;h=cfe762659ebdb6d91128557b35cccb3c08c56144;hb=0877bf6d06de8e6f768534ec40c26bf629618a20;hp=63204dd6a8684fd50897e68dff0b6b8d15ea30c5;hpb=d291ce8580aabc2e4340c9887ea1733325bb1b80;p=dcpomatic.git

diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index 63204dd6a..cfe762659 100644
--- 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) {