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/*
* Copyright 2003-2021 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 "FallbackResampler.hxx"
#include <cassert>
AudioFormat
FallbackPcmResampler::Open(AudioFormat &af, unsigned new_sample_rate)
{
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() noexcept
{
}
template<typename T>
static ConstBuffer<T>
pcm_resample_fallback(PcmBuffer &buffer,
unsigned channels,
unsigned src_rate,
ConstBuffer<T> src,
unsigned dest_rate) noexcept
{
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) noexcept
{
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)
{
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();
}
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