Method open

src/SFML/Audio/SoundFileReaderMp3.cpp:134–166

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std::optional<SoundFileReader::Info> SoundFileReaderMp3::open(InputStream& stream)
{
    // Init mp3 decoder
    if (drmp3_init(&m_decoder, readCallback, seekCallback, tellCallback, nullptr, &stream, nullptr) != 1)
        return std::nullopt;

    // Retrieve the music attributes
    Info info;
    info.channelCount = static_cast<unsigned int>(m_decoder.channels);
    info.sampleRate   = static_cast<unsigned int>(m_decoder.sampleRate);
    info.sampleCount  = drmp3_get_pcm_frame_count(&m_decoder) * m_decoder.channels;

    // MP3 only supports mono/stereo channels
    switch (info.channelCount)
    {
        case 0:
            err() << "No channels in MP3 file" << std::endl;
            break;
        case 1:
            info.channelMap = {SoundChannel::Mono};
            break;
        case 2:
            info.channelMap = {SoundChannel::SideLeft, SoundChannel::SideRight};
            break;
        default:
            err() << "MP3 files with more than 2 channels not supported" << std::endl;
            assert(false);
            break;
    }

    m_numSamples = info.sampleCount;
    return info;
}


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