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#include <QtDebug>
#include <QObject>
#include <limits.h>
#include "encoder/encodermp3.h"
#include "encoder/encodermp3settings.h"
#include "encoder/encodercallback.h"
// Automatic thresholds for switching the encoder to mono
// They have been chosen by testing and to keep the same number
// of values for the slider.
// The threshold of bitrate (CBR/ABR) at which the encoder
// with switch to mono encoding
const int EncoderMp3::MONO_BITRATE_THRESHOLD = 100;
// The threshold of quality (VBR) at which the encoder
// with switch to mono encoding. Values from 0 to 6 encode at 44Khz
const int EncoderMp3::MONO_VBR_THRESHOLD = 8;
// Quality offset to subtract to the quality value when
// switching to mono encoding.
const int EncoderMp3::MONO_VBR_OFFSET = 4;
EncoderMp3::EncoderMp3(EncoderCallback* pCallback)
: m_lameFlags(nullptr),
m_bitrate(128),
m_bufferOut(nullptr),
m_bufferOutSize(0),
m_bufferIn{nullptr, nullptr},
m_bufferInSize(0),
m_pCallback(pCallback) {
}
EncoderMp3::~EncoderMp3() {
flush();
if (m_lameFlags != nullptr) {
lame_close(m_lameFlags);
}
// free requested buffers
if (m_bufferIn[0] != nullptr)
free(m_bufferIn[0]);
if (m_bufferIn[1] != nullptr)
free(m_bufferIn[1]);
if (m_bufferOut != nullptr)
free(m_bufferOut);
}
void EncoderMp3::setEncoderSettings(const EncoderSettings& settings) {
m_bitrate = settings.getQuality();
int modeoption = settings.getSelectedOption(EncoderMp3Settings::ENCODING_MODE_GROUP);
m_encoding_mode = (modeoption==0) ? vbr_off : (modeoption==1) ? vbr_abr : vbr_default;
if (m_encoding_mode == vbr_off) {
if (m_bitrate > MONO_BITRATE_THRESHOLD ) {
m_stereo_mode = JOINT_STEREO;
} else {
m_stereo_mode = MONO;
}
} else {
// Inverting range: vbr 0 best, 9 worst. slider 0 min to max.
int val = settings.getQualityValues().size() - 1 - settings.getQualityIndex();
if (val < MONO_VBR_THRESHOLD) {
m_stereo_mode = JOINT_STEREO;
m_vbr_index = val;
} else {
m_vbr_index = val-4;
m_stereo_mode = MONO;
}
}
// Check if the user has forced a stereo mode.
switch (settings.getChannelMode()) {
case EncoderSettings::ChannelMode::MONO: m_stereo_mode = MONO; break;
case EncoderSettings::ChannelMode::STEREO: m_stereo_mode = JOINT_STEREO; break;
default: break;
}
}
int EncoderMp3::bufferOutGrow(int size) {
if (m_bufferOutSize >= size) {
return 0;
}
m_bufferOut = (unsigned char *)realloc(m_bufferOut, size);
if (m_bufferOut == nullptr) {
return -1;
}
m_bufferOutSize = size;
return 0;
}
int EncoderMp3::bufferInGrow(int size) {
if (m_bufferInSize >= size) {
return 0;
}
m_bufferIn[0] = (float *)realloc(m_bufferIn[0], size * sizeof(float));
m_bufferIn[1] = (float *)realloc(m_bufferIn[1], size * sizeof(float));
if ((m_bufferIn[0] == nullptr) || (m_bufferIn[1] == nullptr)) {
return -1;
}
m_bufferInSize = size;
return 0;
}
// Using this method requires to call method 'write()' or 'sendPackages()'
// depending on which context you use the class (broadcast or recording to HDD)
void EncoderMp3::flush() {
if (m_lameFlags == nullptr) {
return;
}
// Flush also writes ID3 tags.
int rc = lame_encode_flush(m_lameFlags, m_bufferOut, m_bufferOutSize);
if (rc < 0) {
return;
}
// end encoded audio to broadcast or file
m_pCallback->write(nullptr, m_bufferOut, 0, rc);
// Write the lame/xing header.
rc = lame_get_lametag_frame(m_lameFlags, m_bufferOut, m_bufferOutSize);
if (rc != m_bufferOutSize) {
bufferOutGrow(rc);
rc = lame_get_lametag_frame(m_lameFlags, m_bufferOut, m_bufferOutSize);
}
m_pCallback->seek(0);
m_pCallback->write(nullptr, m_bufferOut, 0, rc);
}
void EncoderMp3::encodeBuffer(const CSAMPLE *samples, const int size) {
if (m_lameFlags == nullptr) {
return;
}
int outsize = 0;
int rc = 0;
outsize = (int)((1.25 * size + 7200) + 1);
bufferOutGrow(outsize);
bufferInGrow(size);
// Deinterleave samples. We use normalized floats in the engine [-1.0, 1.0]
// but LAME expects samples in the range [SHRT_MIN, SHRT_MAX].
for (int i = 0; i < size/2; ++i) {
m_bufferIn[0][i] = samples[i*2] * SHRT_MAX;
m_bufferIn[1][i] = samples[i*2+1] * SHRT_MAX;
}
rc = lame_encode_buffer_float(m_lameFlags, m_bufferIn[0], m_bufferIn[1],
size/2, m_bufferOut, m_bufferOutSize);
if (rc < 0) {
return;
}
//write encoded audio to broadcast stream or file
m_pCallback->write(nullptr, m_bufferOut, 0, rc);
}
void EncoderMp3::initStream() {
m_bufferOutSize = (int)((1.25 * 20000 + 7200) + 1);
m_bufferOut = (unsigned char *)malloc(m_bufferOutSize);
m_bufferIn[0] = (float *)malloc(m_bufferOutSize * sizeof(float));
m_bufferIn[1] = (float *)malloc(m_bufferOutSize * sizeof(float));
}
int EncoderMp3::initEncoder(int samplerate, QString errorMessage) {
unsigned long samplerate_in = samplerate;
// samplerate_out 0 means "let LAME pick the appropriate one"
unsigned long samplerate_out = (samplerate_in > 48000 ? 48000 : 0);
m_lameFlags = lame_init();
if (m_lameFlags == nullptr) {
qDebug() << "Unable to initialize lame";
errorMessage = "MP3 recording is not supported. Lame could not be initialized";
return -1;
}
lame_set_in_samplerate(m_lameFlags, samplerate_in);
lame_set_out_samplerate(m_lameFlags, samplerate_out);
// Input channels into the encoder
lame_set_num_channels(m_lameFlags, 2);
// Output channels (on the mp3 file)
// mode = 0,1,2,3 = stereo, jstereo, dual channel (not supported), mono
// Note: JOINT_STEREO is not "forced joint stereo" (That is lame_set_force_ms )
lame_set_mode(m_lameFlags, m_stereo_mode);
if (m_encoding_mode == vbr_off) {
qDebug() << " CBR mode with bitrate: " << m_bitrate;
lame_set_brate(m_lameFlags, m_bitrate);
} else if (m_encoding_mode == vbr_abr) {
qDebug() << " ABR mode with bitrate: " << m_bitrate;
lame_set_VBR(m_lameFlags, vbr_abr);
lame_set_VBR_mean_bitrate_kbps(m_lameFlags, m_bitrate);
} else {
qDebug() << " VBR mode with value: " << m_vbr_index;
lame_set_VBR(m_lameFlags, vbr_default);
lame_set_VBR_q(m_lameFlags, m_vbr_index);
}
lame_set_quality(m_lameFlags, 2);
//ID3 Tag if fields are not NULL
id3tag_init(m_lameFlags);
if (!m_metaDataTitle.isEmpty()) {
id3tag_set_title(m_lameFlags, m_metaDataTitle.toLatin1().constData());
}
if (!m_metaDataArtist.isEmpty()) {
id3tag_set_artist(m_lameFlags, m_metaDataArtist.toLatin1().constData());
}
if (!m_metaDataAlbum.isEmpty()) {
id3tag_set_album(m_lameFlags,m_metaDataAlbum.toLatin1().constData());
}
int ret = lame_init_params(m_lameFlags);
if (ret < 0) {
qDebug() << "Unable to initialize MP3 parameters. return code:" << ret;
errorMessage = "MP3 recording is not supported. Lame could not be initialized.";
return -1;
}
initStream();
return 0;
}
void EncoderMp3::updateMetaData(const QString& artist, const QString& title, const QString& album) {
m_metaDataTitle = title;
m_metaDataArtist = artist;
m_metaDataAlbum = album;
}
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