pcm/SoxrResampler: new resampler option using libsoxr

1 files changed, 95 insertions, 0 deletions

diff --git a/src/pcm/SoxrResampler.cxx b/src/pcm/SoxrResampler.cxx
new file mode 100644
index 000000000..e82ae1481
--- /dev/null
+++ b/src/pcm/SoxrResampler.cxx
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "SoxrResampler.hxx"
+#include "AudioFormat.hxx"
+#include "util/ASCII.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+#include "Log.hxx"
+
+#include <soxr.h>
+
+#include <assert.h>
+
+static constexpr Domain soxr_domain("soxr");
+
+AudioFormat
+SoxrPcmResampler::Open(AudioFormat &af, unsigned new_sample_rate,
+		       Error &error)
+{
+	assert(af.IsValid());
+	assert(audio_valid_sample_rate(new_sample_rate));
+
+	soxr_error_t e;
+	soxr = soxr_create(af.sample_rate, new_sample_rate,
+			   af.channels, &e,
+			   nullptr, nullptr, nullptr);
+	if (soxr == nullptr) {
+		error.Format(soxr_domain,
+			     "soxr initialization has failed: %s", e);
+		return AudioFormat::Undefined();
+	}
+
+	FormatDebug(soxr_domain, "soxr engine '%s'", soxr_engine(soxr));
+
+	channels = af.channels;
+
+	ratio = float(new_sample_rate) / float(af.sample_rate);
+	FormatDebug(soxr_domain,
+		    "samplerate conversion ratio to %.2lf",
+		    ratio);
+
+	/* libsoxr works with floating point samples */
+	af.format = SampleFormat::FLOAT;
+
+	AudioFormat result = af;
+	result.sample_rate = new_sample_rate;
+	return result;
+}
+
+void
+SoxrPcmResampler::Close()
+{
+	soxr_delete(soxr);
+}
+
+ConstBuffer<void>
+SoxrPcmResampler::Resample(ConstBuffer<void> src, Error &error)
+{
+	const size_t frame_size = channels * sizeof(float);
+	assert(src.size % frame_size == 0);
+
+	const size_t n_frames = src.size / frame_size;
+
+	const size_t o_frames = size_t(n_frames * ratio + 0.5);
+
+	float *output_buffer = (float *)buffer.Get(o_frames * frame_size);
+
+	size_t i_done, o_done;
+	soxr_error_t e = soxr_process(soxr, src.data, n_frames, &i_done,
+				      output_buffer, o_frames, &o_done);
+	if (e != nullptr) {
+		error.Format(soxr_domain, "soxr error: %s", e);
+		return nullptr;
+	}
+
+	return { output_buffer, o_done * frame_size };
+}