X-Git-Url: https://main.carlh.net/gitweb/?p=dcpomatic.git;a=blobdiff_plain;f=src%2Flib%2Faudio_buffers.cc;h=63204dd6a8684fd50897e68dff0b6b8d15ea30c5;hp=2ab8e187e3a32f9c3566a669990899cb2caf5649;hb=d291ce8580aabc2e4340c9887ea1733325bb1b80;hpb=a8a0dfd1b21de6c0facf965ab119833ff6f790bf

diff --git a/src/lib/audio_buffers.cc b/src/lib/audio_buffers.cc
index 2ab8e187e..63204dd6a 100644
--- a/src/lib/audio_buffers.cc
+++ b/src/lib/audio_buffers.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012-2013 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2017 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -125,16 +125,13 @@ AudioBuffers::set_frames (int32_t f)
 {
 	DCPOMATIC_ASSERT (f <= _allocated_frames);
 
-	for (int c = 0; c < _channels; ++c) {
-		for (int i = f; i < _frames; ++i) {
-			_data[c][i] = 0;
-		}
+	if (f < _frames) {
+		make_silent (f, _frames - f);
 	}
-
 	_frames = f;
 }
 
-/** Make all samples on all channels silent */
+/** Make all frames silent */
 void
 AudioBuffers::make_silent ()
 {
@@ -151,20 +148,26 @@ AudioBuffers::make_silent (int c)
 {
 	DCPOMATIC_ASSERT (c >= 0 && c < _channels);
 
-	for (int i = 0; i < _frames; ++i) {
-		_data[c][i] = 0;
-	}
+	/* This isn't really allowed, as all-bits-0 is not guaranteed to mean a 0 float,
+	   but it seems that we can get away with it.
+	*/
+	memset (_data[c], 0, _frames * sizeof(float));
 }
 
+/** Make some frames.
+ *  @param from Start frame.
+ *  @param frames Number of frames to silence.
+ */
 void
 AudioBuffers::make_silent (int32_t from, int32_t frames)
 {
 	DCPOMATIC_ASSERT ((from + frames) <= _allocated_frames);
 
 	for (int c = 0; c < _channels; ++c) {
-		for (int i = from; i < (from + frames); ++i) {
-			_data[c][i] = 0;
-		}
+		/* This isn't really allowed, as all-bits-0 is not guaranteed to mean a 0 float,
+		   but it seems that we can get away with it.
+		*/
+		memset (_data[c] + from, 0, frames * sizeof(float));
 	}
 }
 
@@ -198,9 +201,8 @@ AudioBuffers::copy_from (AudioBuffers const * from, int32_t frames_to_copy, int3
  *  @param to Offset to move to.
  *  @param frames Number of frames to move.
  */
-
 void
-AudioBuffers::move (int32_t from, int32_t to, int32_t frames)
+AudioBuffers::move (int32_t frames, int32_t from, int32_t to)
 {
 	if (frames == 0) {
 		return;
@@ -221,6 +223,9 @@ AudioBuffers::move (int32_t from, int32_t to, int32_t frames)
 }
 
 /** Add data from from `from', `from_channel' to our channel `to_channel'.
+ *  @param from Buffers to copy data from.
+ *  @param from_channel Channel index to read in \p from.
+ *  @param to_channel Channel index to accumulate into.
  *  @param gain Linear gain to apply to the data before it is added.
  */
 void
@@ -264,24 +269,32 @@ AudioBuffers::ensure_size (int32_t frames)
 		if (!_data[i]) {
 			throw bad_alloc ();
 		}
-		for (int j = _allocated_frames; j < frames; ++j) {
-			_data[i][j] = 0;
-		}
 	}
 
+	int32_t const old_allocated = _allocated_frames;
 	_allocated_frames = frames;
+	if (old_allocated < _allocated_frames) {
+		make_silent (old_allocated, _allocated_frames - old_allocated);
+	}
 }
 
+/** Mix some other buffers with these ones.  The AudioBuffers must have the same number of channels.
+ *  @param from Audio buffers to get data from.
+ *  @param frames Number of frames to mix.
+ *  @param read_offset Offset within `from' to read from.
+ *  @param write_offset Offset within this to mix into.
+ */
 void
-AudioBuffers::accumulate_frames (AudioBuffers const * from, int32_t read_offset, int32_t write_offset, int32_t frames)
+AudioBuffers::accumulate_frames (AudioBuffers const * from, int32_t frames, int32_t read_offset, int32_t write_offset)
 {
 	DCPOMATIC_ASSERT (_channels == from->channels ());
 	DCPOMATIC_ASSERT (read_offset >= 0);
 	DCPOMATIC_ASSERT (write_offset >= 0);
 
+	float** from_data = from->data ();
 	for (int i = 0; i < _channels; ++i) {
 		for (int j = 0; j < frames; ++j) {
-			_data[i][j + write_offset] += from->data()[i][j + read_offset];
+			_data[i][j + write_offset] += from_data[i][j + read_offset];
 		}
 	}
 }
@@ -310,6 +323,11 @@ AudioBuffers::channel (int c) const
 	return o;
 }
 
+/** Copy all the samples from a channel on another AudioBuffers to a channel on this one.
+ *  @param from AudioBuffers to copy from.
+ *  @param from_channel Channel index in `from' to copy from.
+ *  @param to_channel Channel index in this to copy into, overwriting what's already there.
+ */
 void
 AudioBuffers::copy_channel_from (AudioBuffers const * from, int from_channel, int to_channel)
 {
@@ -317,6 +335,7 @@ AudioBuffers::copy_channel_from (AudioBuffers const * from, int from_channel, in
 	memcpy (data(to_channel), from->data(from_channel), frames() * sizeof (float));
 }
 
+/** Make a copy of these AudioBuffers */
 shared_ptr<AudioBuffers>
 AudioBuffers::clone () const
 {
@@ -324,3 +343,22 @@ AudioBuffers::clone () const
 	b->copy_from (this, frames (), 0, 0);
 	return b;
 }
+
+/** Extend these buffers with the data from another.  The AudioBuffers must have the same number of channels. */
+void
+AudioBuffers::append (shared_ptr<const AudioBuffers> other)
+{
+	DCPOMATIC_ASSERT (channels() == other->channels());
+	ensure_size (_frames + other->frames());
+	copy_from (other.get(), other->frames(), 0, _frames);
+	_frames += other->frames();
+}
+
+/** Remove some frames from the start of these AudioBuffers */
+void
+AudioBuffers::trim_start (int32_t frames)
+{
+	DCPOMATIC_ASSERT (frames <= _frames);
+	move (_frames - frames, frames, 0);
+	set_frames (_frames - frames);
+}