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OpenTTD/src/soundloader_opus.cpp

96 lines
3.4 KiB
C++

/*
* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file sound_opus.cpp Loading of opus sounds. */
#include "stdafx.h"
#include "random_access_file_type.h"
#include "sound_type.h"
#include "soundloader_type.h"
#include <opusfile.h>
#include "safeguards.h"
/** Opus sound loader. */
class SoundLoader_Opus : public SoundLoader {
public:
SoundLoader_Opus() : SoundLoader("opus", "Opus sound loader", 10) {}
static constexpr uint16_t OPUS_SAMPLE_RATE = 48000; ///< OpusFile always decodes at 48kHz.
static constexpr uint8_t OPUS_SAMPLE_BITS = 16; ///< OpusFile op_read() uses 16 bits per sample.
/* For good results, you will need at least 57 bytes (for a pure Opus-only stream). */
static constexpr size_t MIN_OPUS_FILE_SIZE = 57U;
/* It is recommended that this be large enough for at least 120 ms of data at 48 kHz per channel (5760 values per channel).
* Smaller buffers will simply return less data, possibly consuming more memory to buffer the data internally. */
static constexpr size_t DECODE_BUFFER_SAMPLES = 5760 * 2;
static constexpr size_t DECODE_BUFFER_BYTES = DECODE_BUFFER_SAMPLES * sizeof(opus_int16);
bool Load(SoundEntry &sound, bool new_format, std::vector<uint8_t> &data) override
{
if (!new_format) return false;
/* At least 57 bytes are needed for an Opus-only file. */
if (sound.file_size < MIN_OPUS_FILE_SIZE) return false;
/* Test if data is an Ogg Opus stream, as identified by the initial file header. */
auto filepos = sound.file->GetPos();
std::vector<uint8_t> tmp(MIN_OPUS_FILE_SIZE);
sound.file->ReadBlock(tmp.data(), tmp.size());
if (op_test(nullptr, tmp.data(), tmp.size()) != 0) return false;
/* Read the whole file into memory. */
tmp.resize(sound.file_size);
sound.file->SeekTo(filepos, SEEK_SET);
sound.file->ReadBlock(tmp.data(), tmp.size());
int error = 0;
auto of = std::unique_ptr<OggOpusFile, OggOpusFileDeleter>(op_open_memory(tmp.data(), tmp.size(), &error));
if (error != 0) return false;
size_t datapos = 0;
for (;;) {
data.resize(datapos + DECODE_BUFFER_BYTES);
int link_index;
int read = op_read(of.get(), reinterpret_cast<opus_int16 *>(&data[datapos]), DECODE_BUFFER_BYTES, &link_index);
if (read == 0) break;
if (read < 0 || op_channel_count(of.get(), link_index) != 1) {
/* Error reading, or incorrect channel count. */
data.clear();
return false;
}
datapos += read * sizeof(opus_int16);
}
/* OpusFile always decodes at 48kHz. */
sound.channels = 1;
sound.bits_per_sample = OPUS_SAMPLE_BITS;
sound.rate = OPUS_SAMPLE_RATE;
/* We resized by DECODE_BUFFER_BYTES just before finally reading zero bytes, undo this. */
data.resize(data.size() - DECODE_BUFFER_BYTES);
return true;
}
private:
/** Helper class to RAII release an OggOpusFile. */
struct OggOpusFileDeleter {
void operator()(OggOpusFile *of)
{
if (of != nullptr) op_free(of);
}
};
};
static SoundLoader_Opus s_sound_loader_opus;