Aegisub/libaegisub/audio/provider.cpp

138 lines
4.4 KiB
C++

// Copyright (c) 2014, Thomas Goyne <plorkyeran@aegisub.org>
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
// Aegisub Project http://www.aegisub.org/
#include "libaegisub/audio/provider.h"
#include "libaegisub/fs.h"
#include "libaegisub/io.h"
#include "libaegisub/log.h"
#include "libaegisub/util.h"
namespace agi {
void AudioProvider::GetAudioWithVolume(void *buf, int64_t start, int64_t count, double volume) const {
GetAudio(buf, start, count);
if (volume == 1.0) return;
if (bytes_per_sample != 2)
throw agi::InternalError("GetAudioWithVolume called on unconverted audio stream");
auto buffer = static_cast<int16_t *>(buf);
for (size_t i = 0; i < (size_t)count; ++i)
buffer[i] = util::mid(-0x8000, static_cast<int>(buffer[i] * volume + 0.5), 0x7FFF);
}
void AudioProvider::ZeroFill(void *buf, int64_t count) const {
if (bytes_per_sample == 1)
// 8 bit formats are usually unsigned with bias 128
memset(buf, 128, count * channels);
else // While everything else is signed
memset(buf, 0, count * bytes_per_sample * channels);
}
void AudioProvider::GetAudio(void *buf, int64_t start, int64_t count) const {
if (start < 0) {
ZeroFill(buf, std::min(-start, count));
buf = static_cast<char *>(buf) + -start * bytes_per_sample * channels;
count += start;
start = 0;
}
if (start + count > num_samples) {
int64_t zero_count = std::min(count, start + count - num_samples);
count -= zero_count;
ZeroFill(static_cast<char *>(buf) + count * bytes_per_sample * channels, zero_count);
}
if (count <= 0) return;
try {
FillBuffer(buf, start, count);
}
catch (AudioDecodeError const& e) {
// We don't have any good way to report errors here, so just log the
// failure and return silence
LOG_E("audio_provider") << e.GetMessage();
ZeroFill(buf, count);
return;
}
catch (...) {
LOG_E("audio_provider") << "Unknown audio decoding error";
ZeroFill(buf, count);
return;
}
}
namespace {
class writer {
io::Save outfile;
std::ostream& out;
public:
writer(agi::fs::path const& filename) : outfile(filename, true), out(outfile.Get()) { }
template<int N>
void write(const char(&str)[N]) {
out.write(str, N - 1);
}
void write(std::vector<char> const& data) {
out.write(data.data(), data.size());
}
template<typename Dest, typename Src>
void write(Src v) {
auto converted = static_cast<Dest>(v);
out.write(reinterpret_cast<char *>(&converted), sizeof(Dest));
}
};
}
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);
}
}
}