如何从 byte[] 中的音频文件创建 AudioClip

Question

我有存储在另一个数据文件中的音频文件（WAV 和 OGG）（[一些杂项数据...][指示 ogg 和长度的标志][OGG 文件数据][更多杂项数据...]）。我可以很容易地将 OGG 和 WAV 文件数据提取到字节数组中。如何将字节数组转换为 AudioClip 对象？我不想自己解码所有音频或添加扩展。我还需要做这个跨平台。速度并不是很关键，所以像将数据写入临时文件然后使用 WWW 加载它这样的解决方案似乎是可行的，但我不知道如何创建一个跨平台、沙盒安全的临时文件，我希望有一种在内存中完成这一切的方法，所以我不需要破坏磁盘（但如果我必须这样做）。

Answer 1

在将文件数据提取到浮点数组后 - 或在您的情况下将字节数组转换为浮点数组，您可以使用静态 Create 函数创建一个 AudioClip 实例，并分别通过 SetData 函数填充该实例。

这是一个示例代码，与您所指的完全相同： create AudioClip from byte[]

Answer 2

这可能是多余的，但您可以使用我发布的实现 here 从 WAV PCM byte[] 创建一个 AudioClip：

PcmHeader

private readonly struct PcmHeader
{
    #region Public types & data

    public int    BitDepth         { get; }
    public int    AudioSampleSize  { get; }
    public int    AudioSampleCount { get; }
    public ushort Channels         { get; }
    public int    SampleRate       { get; }
    public int    AudioStartIndex  { get; }
    public int    ByteRate         { get; }
    public ushort BlockAlign       { get; }

    #endregion

    #region Constructors & Finalizer

    private PcmHeader(int bitDepth,
        int               audioSize,
        int               audioStartIndex,
        ushort            channels,
        int               sampleRate,
        int               byteRate,
        ushort            blockAlign)
    {
        BitDepth       = bitDepth;
        _negativeDepth = Mathf.Pow(2f, BitDepth - 1f);
        _positiveDepth = _negativeDepth - 1f;

        AudioSampleSize  = bitDepth / 8;
        AudioSampleCount = Mathf.FloorToInt(audioSize / (float)AudioSampleSize);
        AudioStartIndex  = audioStartIndex;

        Channels   = channels;
        SampleRate = sampleRate;
        ByteRate   = byteRate;
        BlockAlign = blockAlign;
    }

    #endregion

    #region Public Methods

    public static PcmHeader FromBytes(byte[] pcmBytes)
    {
        using var memoryStream = new MemoryStream(pcmBytes);
        return FromStream(memoryStream);
    }

    public static PcmHeader FromStream(Stream pcmStream)
    {
        pcmStream.Position = SizeIndex;
        using BinaryReader reader = new BinaryReader(pcmStream);

        int    headerSize      = reader.ReadInt32();  // 16
        ushort audioFormatCode = reader.ReadUInt16(); // 20

        string audioFormat = GetAudioFormatFromCode(audioFormatCode);
        if (audioFormatCode != 1 && audioFormatCode == 65534)
        {
            // Only uncompressed PCM wav files are supported.
            throw new ArgumentOutOfRangeException(nameof(pcmStream),
                                                  $"Detected format code '{audioFormatCode}' {audioFormat}, but only PCM and WaveFormatExtensible uncompressed formats are currently supported.");
        }

        ushort channelCount = reader.ReadUInt16(); // 22
        int    sampleRate   = reader.ReadInt32();  // 24
        int    byteRate     = reader.ReadInt32();  // 28
        ushort blockAlign   = reader.ReadUInt16(); // 32
        ushort bitDepth     = reader.ReadUInt16(); //34

        pcmStream.Position = SizeIndex + headerSize + 2 * sizeof(int); // Header end index
        int audioSize = reader.ReadInt32();                            // Audio size index

        return new PcmHeader(bitDepth, audioSize, (int)pcmStream.Position, channelCount, sampleRate, byteRate, blockAlign); // audio start index
    }

    public float NormalizeSample(float rawSample)
    {
        float sampleDepth = rawSample < 0 ? _negativeDepth : _positiveDepth;
        return rawSample / sampleDepth;
    }

    #endregion

    #region Private Methods

    private static string GetAudioFormatFromCode(ushort code)
    {
        switch (code)
        {
            case 1:     return "PCM";
            case 2:     return "ADPCM";
            case 3:     return "IEEE";
            case 7:     return "?-law";
            case 65534: return "WaveFormatExtensible";
            default:    throw new ArgumentOutOfRangeException(nameof(code), code, "Unknown wav code format.");
        }
    }

    #endregion

    #region Private types & Data

    private const int SizeIndex = 16;

    private readonly float _positiveDepth;
    private readonly float _negativeDepth;

    #endregion
}

PcmData

private readonly struct PcmData
{
    #region Public types & data

    public float[] Value      { get; }
    public int     Length     { get; }
    public int     Channels   { get; }
    public int     SampleRate { get; }

    #endregion

    #region Constructors & Finalizer

    private PcmData(float[] value, int channels, int sampleRate)
    {
        Value      = value;
        Length     = value.Length;
        Channels   = channels;
        SampleRate = sampleRate;
    }

    #endregion

    #region Public Methods

    public static PcmData FromBytes(byte[] bytes)
    {
        if (bytes == null)
        {
            throw new ArgumentNullException(nameof(bytes));
        }

        PcmHeader pcmHeader = PcmHeader.FromBytes(bytes);
        if (pcmHeader.BitDepth != 16 && pcmHeader.BitDepth != 32 && pcmHeader.BitDepth != 8)
        {
            throw new ArgumentOutOfRangeException(nameof(pcmHeader.BitDepth), pcmHeader.BitDepth, "Supported values are: 8, 16, 32");
        }

        float[] samples = new float[pcmHeader.AudioSampleCount];
        for (int i = 0; i < samples.Length; ++i)
        {
            int   byteIndex = pcmHeader.AudioStartIndex + i * pcmHeader.AudioSampleSize;
            float rawSample;
            switch (pcmHeader.BitDepth)
            {
                case 8:
                    rawSample = bytes[byteIndex];
                    break;

                case 16:
                    rawSample = BitConverter.ToInt16(bytes, byteIndex);
                    break;

                case 32:
                    rawSample = BitConverter.ToInt32(bytes, byteIndex);
                    break;

                default: throw new ArgumentOutOfRangeException(nameof(pcmHeader.BitDepth), pcmHeader.BitDepth, "Supported values are: 8, 16, 32");
            }

            samples[i] = pcmHeader.NormalizeSample(rawSample); // normalize sample between [-1f, 1f]
        }

        return new PcmData(samples, pcmHeader.Channels, pcmHeader.SampleRate);
    }

    #endregion
}

用法

public static AudioClip FromPcmBytes(byte[] bytes, string clipName = "pcm")
{
    clipName.ThrowIfNullOrWhitespace(nameof(clipName));
    var pcmData   = PcmData.FromBytes(bytes);
    var audioClip = AudioClip.Create(clipName, pcmData.Length, pcmData.Channels, pcmData.SampleRate, false);
    audioClip.SetData(pcmData.Value, 0);
    return audioClip;
}

请注意，AudioClip.Create 提供了带有 Read 和 SetPosition 回调的重载，以防您需要使用源 Stream 而不是字节块。