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136 lines
3.1 KiB
C++

// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright The Music Player Daemon Project
#include "LibsamplerateResampler.hxx"
#include "config/Block.hxx"
#include "lib/fmt/RuntimeError.hxx"
#include "util/ASCII.hxx"
#include "util/Domain.hxx"
#include "util/SpanCast.hxx"
#include "Log.hxx"
#include <cassert>
#include <stdlib.h>
#include <string.h>
static constexpr Domain libsamplerate_domain("libsamplerate");
static int lsr_converter = SRC_SINC_FASTEST;
static bool
lsr_parse_converter(const char *s)
{
assert(s != nullptr);
if (*s == 0)
return true;
char *endptr;
long l = strtol(s, &endptr, 10);
if (*endptr == 0 && src_get_name(l) != nullptr) {
lsr_converter = l;
return true;
}
size_t length = strlen(s);
for (int i = 0;; ++i) {
const char *name = src_get_name(i);
if (name == nullptr)
break;
if (StringEqualsCaseASCII(s, name, length)) {
lsr_converter = i;
return true;
}
}
return false;
}
void
pcm_resample_lsr_global_init(const ConfigBlock &block)
{
const char *converter = block.GetBlockValue("type", "2");
if (!lsr_parse_converter(converter))
throw FmtRuntimeError("unknown samplerate converter {:?}",
converter);
FmtDebug(libsamplerate_domain,
"libsamplerate converter {:?}",
src_get_name(lsr_converter));
}
AudioFormat
LibsampleratePcmResampler::Open(AudioFormat &af, unsigned new_sample_rate)
{
assert(af.IsValid());
assert(audio_valid_sample_rate(new_sample_rate));
src_rate = af.sample_rate;
dest_rate = new_sample_rate;
channels = af.channels;
/* libsamplerate works with floating point samples */
af.format = SampleFormat::FLOAT;
int src_error;
state = src_new(lsr_converter, channels, &src_error);
if (!state)
throw FmtRuntimeError("libsamplerate initialization has failed: {}",
src_strerror(src_error));
memset(&data, 0, sizeof(data));
data.src_ratio = double(new_sample_rate) / double(af.sample_rate);
FmtDebug(libsamplerate_domain,
"setting samplerate conversion ratio to {:.2}",
data.src_ratio);
src_set_ratio(state, data.src_ratio);
AudioFormat result = af;
result.sample_rate = new_sample_rate;
return result;
}
void
LibsampleratePcmResampler::Close() noexcept
{
state = src_delete(state);
}
void
LibsampleratePcmResampler::Reset() noexcept
{
src_reset(state);
}
inline std::span<const float>
LibsampleratePcmResampler::Resample2(std::span<const float> src)
{
assert(src.size() % channels == 0);
const unsigned src_frames = src.size() / channels;
const unsigned dest_frames =
(src_frames * dest_rate + src_rate - 1) / src_rate;
size_t data_out_size = dest_frames * sizeof(float) * channels;
data.data_in = const_cast<float *>(src.data());
data.data_out = (float *)buffer.Get(data_out_size);
data.input_frames = src_frames;
data.output_frames = dest_frames;
int result = src_process(state, &data);
if (result != 0)
throw FmtRuntimeError("libsamplerate has failed: {}",
src_strerror(result));
return {data.data_out, size_t(data.output_frames_gen * channels)};
}
std::span<const std::byte>
LibsampleratePcmResampler::Resample(std::span<const std::byte> src)
{
return std::as_bytes(Resample2(FromBytesStrict<const float>(src)));
}