JUCE/modules/juce_audio_formats/codecs/juce_LAMEEncoderAudioFormat.cpp

/*
  ==============================================================================

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2020 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For this technical preview, this file is not subject to commercial licensing.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

#if JUCE_USE_LAME_AUDIO_FORMAT

class LAMEEncoderAudioFormat::Writer   : public AudioFormatWriter
{
public:
    Writer (OutputStream* destStream, const String& formatName,
            const File& appFile, int vbr, int cbr,
            double sampleRateIn, unsigned int numberOfChannels,
            int bitsPerSampleIn, const StringPairArray& metadata)
        : AudioFormatWriter (destStream, formatName, sampleRateIn,
                             numberOfChannels, (unsigned int) bitsPerSampleIn),
          vbrLevel (vbr), cbrBitrate (cbr)
    {
        WavAudioFormat wavFormat;

        if (auto out = tempWav.getFile().createOutputStream())
        {
            writer.reset (wavFormat.createWriterFor (out.release(), sampleRateIn, numChannels,
                                                     bitsPerSampleIn, metadata, 0));

            args.add (appFile.getFullPathName());

            args.add ("--quiet");

            if (cbrBitrate == 0)
            {
                args.add ("--vbr-new");
                args.add ("-V");
                args.add (String (vbrLevel));
            }
            else
            {
                args.add ("--cbr");
                args.add ("-b");
                args.add (String (cbrBitrate));
            }

            addMetadataArg (metadata, "id3title",       "--tt");
            addMetadataArg (metadata, "id3artist",      "--ta");
            addMetadataArg (metadata, "id3album",       "--tl");
            addMetadataArg (metadata, "id3comment",     "--tc");
            addMetadataArg (metadata, "id3date",        "--ty");
            addMetadataArg (metadata, "id3genre",       "--tg");
            addMetadataArg (metadata, "id3trackNumber", "--tn");
        }
    }

    void addMetadataArg (const StringPairArray& metadata, const char* key, const char* lameFlag)
    {
        auto value = metadata.getValue (key, {});

        if (value.isNotEmpty())
        {
            args.add (lameFlag);
            args.add (value);
        }
    }

    ~Writer()
    {
        if (writer != nullptr)
        {
            writer = nullptr;

            if (! convertToMP3())
                convertToMP3(); // try again
        }
    }

    bool write (const int** samplesToWrite, int numSamples)
    {
        return writer != nullptr && writer->write (samplesToWrite, numSamples);
    }

private:
    int vbrLevel, cbrBitrate;
    TemporaryFile tempWav { ".wav" };
    std::unique_ptr<AudioFormatWriter> writer;
    StringArray args;

    bool runLameChildProcess (const TemporaryFile& tempMP3, const StringArray& processArgs) const
    {
        ChildProcess cp;

        if (cp.start (processArgs))
        {
            auto childOutput = cp.readAllProcessOutput();
            DBG (childOutput); ignoreUnused (childOutput);

            cp.waitForProcessToFinish (10000);
            return tempMP3.getFile().getSize() > 0;
        }

        return false;
    }

    bool convertToMP3() const
    {
        TemporaryFile tempMP3 (".mp3");

        StringArray args2 (args);
        args2.add (tempWav.getFile().getFullPathName());
        args2.add (tempMP3.getFile().getFullPathName());

        DBG (args2.joinIntoString (" "));

        if (runLameChildProcess (tempMP3, args2))
        {
            FileInputStream fis (tempMP3.getFile());

            if (fis.openedOk() && output->writeFromInputStream (fis, -1) > 0)
            {
                output->flush();
                return true;
            }
        }

        return false;
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Writer)
};

//==============================================================================
LAMEEncoderAudioFormat::LAMEEncoderAudioFormat (const File& lameApplication)
    : AudioFormat ("MP3 file", ".mp3"),
      lameApp (lameApplication)
{
}

LAMEEncoderAudioFormat::~LAMEEncoderAudioFormat()
{
}

bool LAMEEncoderAudioFormat::canHandleFile (const File&)
{
    return false;
}

Array<int> LAMEEncoderAudioFormat::getPossibleSampleRates()
{
    return { 32000, 44100, 48000 };
}

Array<int> LAMEEncoderAudioFormat::getPossibleBitDepths()
{
    return { 16 };
}

bool LAMEEncoderAudioFormat::canDoStereo()      { return true; }
bool LAMEEncoderAudioFormat::canDoMono()        { return true; }
bool LAMEEncoderAudioFormat::isCompressed()     { return true; }

StringArray LAMEEncoderAudioFormat::getQualityOptions()
{
    static const char* vbrOptions[] = { "VBR quality 0 (best)", "VBR quality 1", "VBR quality 2", "VBR quality 3",
                                        "VBR quality 4 (normal)", "VBR quality 5", "VBR quality 6", "VBR quality 7",
                                        "VBR quality 8", "VBR quality 9 (smallest)", nullptr };
    StringArray opts (vbrOptions);

    const int cbrRates[] = { 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320 };

    for (int i = 0; i < numElementsInArray (cbrRates); ++i)
        opts.add (String (cbrRates[i]) + " Kb/s CBR");

    return opts;
}

AudioFormatReader* LAMEEncoderAudioFormat::createReaderFor (InputStream*, const bool)
{
    return nullptr;
}

AudioFormatWriter* LAMEEncoderAudioFormat::createWriterFor (OutputStream* streamToWriteTo,
                                                            double sampleRateToUse,
                                                            unsigned int numberOfChannels,
                                                            int bitsPerSample,
                                                            const StringPairArray& metadataValues,
                                                            int qualityOptionIndex)
{
    if (streamToWriteTo == nullptr)
        return nullptr;

    int vbr = 4;
    int cbr = 0;

    const String qual (getQualityOptions() [qualityOptionIndex]);

    if (qual.contains ("VBR"))
        vbr = qual.retainCharacters ("0123456789").getIntValue();
    else
        cbr = qual.getIntValue();

    return new Writer (streamToWriteTo, getFormatName(), lameApp, vbr, cbr,
                       sampleRateToUse, numberOfChannels, bitsPerSample, metadataValues);
}

#endif

} // namespace juce