void SaveAudioClip(AudioProvider const& provider, fs::path const& path, int start_time, int end_time) {
const auto max_samples = provider.GetNumSamples();
const auto start_sample = std::min(max_samples, ((int64_t)start_time * provider.GetSampleRate() + 999) / 1000);
const auto end_sample = util::mid(start_sample, ((int64_t)end_time * provider.GetSampleRate() + 999) / 1000, max_samples);
const size_t bytes_per_sample = provider.GetBytesPerSample() * provider.GetChannels();
const size_t bufsize = (end_sample - start_sample) * bytes_per_sample;
writer out{path};
out.write("RIFF");
out.write<int32_t>(bufsize + 36);
out.write("WAVEfmt ");
out.write<int32_t>(16); // Size of chunk
out.write<int16_t>(1); // compression format (PCM)
out.write<int16_t>(provider.GetChannels());
out.write<int32_t>(provider.GetSampleRate());
out.write<int32_t>(provider.GetSampleRate() * provider.GetChannels() * provider.GetBytesPerSample());
out.write<int16_t>(provider.GetChannels() * provider.GetBytesPerSample());
out.write<int16_t>(provider.GetBytesPerSample() * 8);
out.write("data");
out.write<int32_t>(bufsize);
// samples per read
size_t spr = 65536 / bytes_per_sample;
std::vector<char> buf;
for (int64_t i = start_sample; i < end_sample; i += spr) {
spr = std::min<size_t>(spr, end_sample - i);
buf.resize(spr * bytes_per_sample);
provider.GetAudio(&buf[0], i, spr);
out.write(buf);
}
}
//////////////////////
// PortAudio callback
int PortAudioPlayer::paCallback(void *inputBuffer, void *outputBuffer, unsigned long framesPerBuffer, PaTimestamp outTime, void *userData) {
// Get provider
PortAudioPlayer *player = (PortAudioPlayer *) userData;
AudioProvider *provider = player->GetProvider();
int end = 0;
// Calculate how much left
__int64 lenAvailable = player->endPos - player->playPos;
uint64_t avail = 0;
if (lenAvailable > 0) {
avail = lenAvailable;
if (avail > framesPerBuffer) {
lenAvailable = framesPerBuffer;
avail = lenAvailable;
}
}
else {
lenAvailable = 0;
avail = 0;
}
// Play something
if (lenAvailable > 0) {
provider->GetAudio(outputBuffer,player->playPos,lenAvailable);
}
// Pad end with blank
if (avail < (uint64_t) framesPerBuffer) {
//provider->softStop = true;
}
// Set volume
short *output = (short*) outputBuffer;
for (unsigned int i=0;i<avail;i++) output[i] = MID(-(1<<15),int(output[i] * player->GetVolume()),(1<<15)-1);
// Fill rest with blank
for (unsigned int i=avail;i<framesPerBuffer;i++) output[i]=0;
// Set play position (and real one)
player->playPos += framesPerBuffer;
player->realPlayPos = (__int64)(Pa_StreamTime(player->stream) - player->paStart) + player->startPos;
// Cap to start if lower
return end;
}