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#include "resampler.h"
namespace audiere {
Resampler::Resampler(SampleSource* source, int rate) {
m_source = source;
m_rate = rate;
m_source->getFormat(
m_native_channel_count,
m_native_sample_rate,
m_native_sample_format);
m_shift = 1;
fillBuffers();
resetState();
}
void
Resampler::getFormat(
int& channel_count,
int& sample_rate,
SampleFormat& sample_format)
{
channel_count = 2;
sample_rate = m_rate;
sample_format = SF_S16;
}
int
Resampler::read(const int frame_count, void* buffer) {
s16* out = (s16*)buffer;
int left = frame_count;
sample_t tmp_l[BUFFER_SIZE];
sample_t tmp_r[BUFFER_SIZE];
float delta = m_shift * m_native_sample_rate / m_rate;
if (m_shift == 0) { // If shift is zero, which shouldn't be the case, use a shift of 1.
delta = float(m_native_sample_rate) / m_rate;
}
while (left > 0) {
int transfer = std::min(left, int(BUFFER_SIZE));
memset(tmp_l, 0, transfer * sizeof(sample_t));
int rv = dumb_resample(&m_resampler_l, tmp_l, transfer, delta);
if (rv == 0) {
fillBuffers();
if (m_buffer_length == 0) {
return frame_count - left;
} else {
m_resampler_l.pos = m_resampler_l.subpos = m_resampler_l.start = 0;
m_resampler_l.end = m_buffer_length;
m_resampler_l.dir = 1;
m_resampler_r.pos = m_resampler_r.subpos = m_resampler_r.start = 0;
m_resampler_r.end = m_buffer_length;
m_resampler_r.dir = 1;
continue;
}
}
if (m_native_channel_count == 2) {
memset(tmp_r, 0, transfer * sizeof(sample_t));
int rv2 = dumb_resample(&m_resampler_r, tmp_r, transfer, delta);
ADR_ASSERT(rv == rv2, "resamplers returned different sample counts");
for (int i = 0; i < rv; i++) {
*out++ = clamp(-32768, tmp_l[i], 32767);
*out++ = clamp(-32768, tmp_r[i], 32767);
}
} else {
for (int i = 0; i < rv; i++) {
s16 sample = clamp(-32768, tmp_l[i], 32767);
*out++ = sample;
*out++ = sample;
}
}
left -= rv;
}
return frame_count;
}
void
Resampler::reset() {
m_source->reset();
fillBuffers();
resetState();
}
inline s16 u8tos16(u8 u) {
return (s16(u) - 128) * 256;
}
void
Resampler::fillBuffers() {
// we only support channels in [1, 2] and bits in [8, 16] now
u8 initial_buffer[BUFFER_SIZE * 4];
unsigned read = m_source->read(BUFFER_SIZE, initial_buffer);
sample_t* out_l = m_native_buffer_l;
sample_t* out_r = m_native_buffer_r;
if (m_native_channel_count == 1) {
if (m_native_sample_format == SF_U8) {
// channels = 1, bits = 8
u8* in = initial_buffer;
for (unsigned i = 0; i < read; ++i) {
s16 sample = u8tos16(*in++);
*out_l++ = sample;
}
} else {
// channels = 1, bits = 16
s16* in = (s16*)initial_buffer;
for (unsigned i = 0; i < read; ++i) {
s16 sample = *in++;
*out_l++ = sample;
}
}
} else {
if (m_native_sample_format == SF_U8) {
// channels = 2, bits = 8
u8* in = initial_buffer;
for (unsigned i = 0; i < read; ++i) {
*out_l++ = u8tos16(*in++);
*out_r++ = u8tos16(*in++);
}
} else {
// channels = 2, bits = 16
s16* in = (s16*)initial_buffer;
for (unsigned i = 0; i < read; ++i) {
*out_l++ = *in++;
*out_r++ = *in++;
}
}
}
m_buffer_length = read;
}
void
Resampler::resetState() {
dumb_reset_resampler(&m_resampler_l, m_native_buffer_l, 0, 0,
m_buffer_length);
if (m_native_channel_count == 2) {
dumb_reset_resampler(&m_resampler_r, m_native_buffer_r, 0, 0,
m_buffer_length);
}
}
bool
Resampler::isSeekable() {
return m_source->isSeekable();
}
int
Resampler::getLength() {
return m_source->getLength();
}
void
Resampler::setPosition(int position) {
m_source->setPosition(position);
fillBuffers();
resetState();
}
int
Resampler::getPosition() {
int position = m_source->getPosition() - m_buffer_length +
m_resampler_l.pos;
while (position < 0) {
position += m_source->getLength();
}
return position;
}
bool
Resampler::getRepeat() {
return m_source->getRepeat();
}
void
Resampler::setRepeat(bool repeat) {
/// @todo if we've already read to the end, do we try to read more?
m_source->setRepeat(repeat);
}
int Resampler::getTagCount() { return m_source->getTagCount(); }
const char* Resampler::getTagKey(int i) { return m_source->getTagKey(i); }
const char* Resampler::getTagValue(int i) { return m_source->getTagValue(i); }
const char* Resampler::getTagType(int i) { return m_source->getTagType(i); }
void
Resampler::setPitchShift(float shift) {
m_shift = shift;
}
float
Resampler::getPitchShift() {
return m_shift;
}
}
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