How to convert 16Bit byte array to audio clip data correctly?

问题

I work with Media Foundataion and what I need to do is convert sound sample frame from byte to audio float data. In order to do it I use such method (that I found somewhere at google):

    private static float[] Convert16BitByteArrayToAudioClipData(byte[] source, int headerOffset, int dataSize)
    {
        int wavSize = BitConverter.ToInt32(source, headerOffset);
        headerOffset += sizeof(int);
        Debug.AssertFormat(wavSize > 0 && wavSize == dataSize, "Failed to get valid 16-bit wav size: {0} from data bytes: {1} at offset: {2}", wavSize, dataSize, headerOffset);

        int x = sizeof(Int16); // block size = 2
        int convertedSize = wavSize / x;

        float[] data = new float[convertedSize];

        Int16 maxValue = Int16.MaxValue;
        int i = 0;

        while (i < convertedSize)
        {
            int offset = i * x + headerOffset;
            data[i] = (float)BitConverter.ToInt16(source, offset) / maxValue;
            ++i;
        }

        Debug.AssertFormat(data.Length == convertedSize, "AudioClip .wav data is wrong size: {0} == {1}", data.Length, convertedSize);

        return data;
    }

I use it like this :

...
byte[] source = ...; // lenght 43776

... = Convert16BitByteArrayToAudioClipData(source , 0, 0);
...

Looks like this method works wrong, because if I pass an array with size 43776 as a result in while loop at index i = 21886 offset value will be offset = 43776 it lead to exception at this next method

data[i] = (float)BitConverter.ToInt16(source /*43776*/, offset /*43776*/) / maxValue;

because this values could not be the same.

Question is - how to fix this method? Or maybe someone can advice what to use instead?

EDIT

    private static float[] Convert16BitByteArrayToAudioClipData(byte[] source)
    {
        float[] data = new float[source.Length];

        for (int i = 0; i < source.Length; i++)
        {
            data[i] = (float) source[i];
        }

        return data;
    }

回答1:

Integers need to become -1..+1 floating point values

    private static float[] Convert16BitByteArrayToAudioClipData(byte[] source)
    {
        float[] data = new float[source.Length];

        for (int i = 0; i < source.Length; i++)
        {
            data[i] = ((float) source[i] / Int16.MaxValue); // <<---
        }

        return data;
    }

回答2:

Eventually I did it this way:

    public static float[] Convert16BitByteArrayToAudioClipData(byte[] source)
    {
        int x = sizeof(Int16); 
        int convertedSize = source.Length / x;
        float[] data = new float[convertedSize];
        Int16 maxValue = Int16.MaxValue;

        for (int i = 0; i < convertedSize; i++)
        {
            int offset = i * x;
            data[i] = (float)BitConverter.ToInt16(source, offset) / maxValue;
            ++i;
        }

        return data;
    }

来源：https://stackoverflow.com/questions/65023000/how-to-convert-16bit-byte-array-to-audio-clip-data-correctly

标签

audio

ms-media-foundation