android - 如何将 float 缓冲区写入到wav文件android？

Question

我在Android中使用AudioRecord在PCM float 32中进行录制，需要将其保存到wave文件中，如何将音频的float数组转换为wave文件？

这是我的录音设置:

private AudioRecord audioRecord;
private static final int RECORDER_CHANNELS = AudioFormat.CHANNEL_IN_MONO;
private static final int RECORDER_AUDIO_ENCODING = AudioFormat.ENCODING_PCM_FLOAT;
private int bufferSize;

public CoughAudioRecord(int samplingRate, String MODEL_FILE){
    //load and configure audio recorder
    bufferSize = 2 * AudioRecord.getMinBufferSize(samplingRate, RECORDER_CHANNELS, RECORDER_AUDIO_ENCODING);
    audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, samplingRate,
           RECORDER_CHANNELS, RECORDER_AUDIO_ENCODING, bufferSize);
}

以及当前我如何阅读音频:

final int readSize = audioRecord.read(audioData, 0, audioData.length, AudioRecord.READ_BLOCKING);

Answer 1

没有内置的解决方案/库，这太奇怪了。如果某人有空余时间来创造一天，那应该很棒。此解决方案是Internet上某些方面的组合。

Create 32bit float wav file in python?

https://android.googlesource.com/platform/frameworks/base/+/android-4.4_r1/core/java/android/speech/srec/WaveHeader.java

http://soundfile.sapp.org/doc/WaveFormat/

编码:

import java.io.OutputStream

class WaveFileWriter(
    private val out: OutputStream,
    private val sampleRate: Int,
    private val numChannels: Short,
) {

    fun write(waveform: FloatArray) {
        val mNumBytes = 4 * waveform.size
        val audioFormat: Short = 3
        val bitPerSample: Short = 32

        writeHeader(mNumBytes, audioFormat, bitPerSample)
        waveform.map(Float::toRawBits).forEach(this::writeInt)

        out.flush()
        out.close()
    }


    private fun writeHeader(numBytes: Int, audioFormat: Short, bitPerSample: Short) {
        val bytePerSample = bitPerSample / 8
        val byteRate = numChannels * sampleRate * bytePerSample
        val blockAlign = (numChannels * bytePerSample).toShort()

        /* RIFF header */
        writeId("RIFF")
        writeInt(36 + numBytes)
        writeId("WAVE")
        /* fmt chunk */
        writeId("fmt ")
        writeInt(16)
        writeShort(audioFormat)
        writeShort(numChannels)
        writeInt(sampleRate)
        writeInt(byteRate)
        writeShort(blockAlign)
        writeShort(bitPerSample)
        /* data chunk */
        writeId("data")
        writeInt(numBytes)
    }

    private fun writeId(id: String) = id.map(Char::toInt).forEach(out::write)

    private fun writeInt(i: Int) {
        out.write(i shr 0)
        out.write(i shr 8)
        out.write(i shr 16)
        out.write(i shr 24)
    }


    private fun writeShort(i: Short) {
        out.write(i.toInt() shr 0)
        out.write(i.toInt() shr 8)
    }
}