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-rw-r--r--src/pcm/FallbackResampler.cxx147
1 files changed, 147 insertions, 0 deletions
diff --git a/src/pcm/FallbackResampler.cxx b/src/pcm/FallbackResampler.cxx
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+++ b/src/pcm/FallbackResampler.cxx
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+/*
+ * Copyright (C) 2003-2014 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 "FallbackResampler.hxx"
+
+#include <assert.h>
+
+AudioFormat
+FallbackPcmResampler::Open(AudioFormat &af, unsigned new_sample_rate,
+ gcc_unused Error &error)
+{
+ assert(af.IsValid());
+ assert(audio_valid_sample_rate(new_sample_rate));
+
+ switch (af.format) {
+ case SampleFormat::UNDEFINED:
+ assert(false);
+ gcc_unreachable();
+
+ case SampleFormat::S8:
+ af.format = SampleFormat::S16;
+ break;
+
+ case SampleFormat::S16:
+ case SampleFormat::FLOAT:
+ case SampleFormat::S24_P32:
+ case SampleFormat::S32:
+ break;
+
+ case SampleFormat::DSD:
+ af.format = SampleFormat::FLOAT;
+ break;
+ }
+
+ format = af;
+ out_rate = new_sample_rate;
+
+ AudioFormat result = af;
+ result.sample_rate = new_sample_rate;
+ return result;
+}
+
+void
+FallbackPcmResampler::Close()
+{
+}
+
+template<typename T>
+static ConstBuffer<T>
+pcm_resample_fallback(PcmBuffer &buffer,
+ unsigned channels,
+ unsigned src_rate,
+ ConstBuffer<T> src,
+ unsigned dest_rate)
+{
+ unsigned dest_pos = 0;
+ unsigned src_frames = src.size / channels;
+ unsigned dest_frames =
+ (src_frames * dest_rate + src_rate - 1) / src_rate;
+ unsigned dest_samples = dest_frames * channels;
+ size_t dest_size = dest_samples * sizeof(*src.data);
+ T *dest_buffer = (T *)buffer.Get(dest_size);
+
+ assert((src.size % channels) == 0);
+
+ switch (channels) {
+ case 1:
+ while (dest_pos < dest_samples) {
+ unsigned src_pos = dest_pos * src_rate / dest_rate;
+
+ dest_buffer[dest_pos++] = src[src_pos];
+ }
+ break;
+ case 2:
+ while (dest_pos < dest_samples) {
+ unsigned src_pos = dest_pos * src_rate / dest_rate;
+ src_pos &= ~1;
+
+ dest_buffer[dest_pos++] = src[src_pos];
+ dest_buffer[dest_pos++] = src[src_pos + 1];
+ }
+ break;
+ }
+
+ return { dest_buffer, dest_samples };
+}
+
+template<typename T>
+static ConstBuffer<void>
+pcm_resample_fallback_void(PcmBuffer &buffer,
+ unsigned channels,
+ unsigned src_rate,
+ ConstBuffer<void> src,
+ unsigned dest_rate)
+{
+ const auto typed_src = ConstBuffer<T>::FromVoid(src);
+ return pcm_resample_fallback(buffer, channels, src_rate, typed_src,
+ dest_rate).ToVoid();
+}
+
+ConstBuffer<void>
+FallbackPcmResampler::Resample(ConstBuffer<void> src, gcc_unused Error &error)
+{
+ switch (format.format) {
+ case SampleFormat::UNDEFINED:
+ case SampleFormat::S8:
+ case SampleFormat::DSD:
+ assert(false);
+ gcc_unreachable();
+
+ case SampleFormat::S16:
+ return pcm_resample_fallback_void<int16_t>(buffer,
+ format.channels,
+ format.sample_rate,
+ src,
+ out_rate);
+
+ case SampleFormat::FLOAT:
+ case SampleFormat::S24_P32:
+ case SampleFormat::S32:
+ return pcm_resample_fallback_void<int32_t>(buffer,
+ format.channels,
+ format.sample_rate,
+ src,
+ out_rate);
+ }
+
+ assert(false);
+ gcc_unreachable();
+}