X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Faudio_buffers.cc;h=56ca7a94b18c5860e3800f03740baa2c09480d59;hb=1c13441a19aa387ddd8ac0c972207ccbbe3114d8;hp=a15288a3b86c64b66f5567a3f93e7321e6e48279;hpb=fd970b185e9357522f5d12d62800df8769764729;p=dcpomatic.git

diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index a15288a3b..56ca7a94b 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"
 
@@ -72,6 +73,9 @@ AudioBuffers::~AudioBuffers ()
 void
 AudioBuffers::allocate (int channels, int frames)
 {
+	assert (frames >= 0);
+	assert (channels >= 0);
+
 	_channels = channels;
 	_frames = frames;
 	_allocated_frames = frames;
@@ -171,6 +175,11 @@ AudioBuffers::make_silent (int from, int frames)
 void
 AudioBuffers::copy_from (AudioBuffers const * from, int frames_to_copy, int read_offset, int write_offset)
 {
+	if (frames_to_copy == 0) {
+		/* Prevent the asserts from firing if there is nothing to do */
+		return;
+	}
+	
 	assert (from->channels() == channels());
 
 	assert (from);
@@ -209,9 +218,11 @@ 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);
@@ -221,7 +232,7 @@ 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;
 	}
 }
 
@@ -252,6 +263,8 @@ void
 AudioBuffers::accumulate_frames (AudioBuffers const * from, int read_offset, int write_offset, int frames)
 {
 	assert (_channels == from->channels ());
+	assert (read_offset >= 0);
+	assert (write_offset >= 0);
 
 	for (int i = 0; i < _channels; ++i) {
 		for (int j = 0; j < frames; ++j) {
@@ -260,3 +273,41 @@ 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;
+		}
+	}
+}
+
+/** @param c Channel index.
+ *  @return AudioBuffers object containing only channel `c' from this AudioBuffers.
+ */
+shared_ptr<AudioBuffers>
+AudioBuffers::channel (int c) const
+{
+	shared_ptr<AudioBuffers> o (new AudioBuffers (1, frames ()));
+	o->copy_channel_from (this, c, 0);
+	return o;
+}
+
+void
+AudioBuffers::copy_channel_from (AudioBuffers const * from, int from_channel, int to_channel)
+{
+	assert (from->frames() == frames());
+	memcpy (data(to_channel), from->data(from_channel), frames() * sizeof (float));
+}
+
+shared_ptr<AudioBuffers>
+AudioBuffers::clone () const
+{
+	shared_ptr<AudioBuffers> b (new AudioBuffers (channels (), frames ()));
+	b->copy_from (this, frames (), 0, 0);
+	return b;
+}