[英]How play .WAV backwards?
我有.WAV文件。 我需要倒退。 我該怎么做? 我從文件讀取InputStream的數據,然后將其轉換為字節數組。 反轉此數組,然后將此數組寫入另一個文件? 錯誤的邏輯在哪里?
public void copyWaveFile(String inFilename,String outFilename){
FileInputStream in = null;
FileOutputStream out = null;
long totalAudioLen = 0;`enter code here`
long totalDataLen = totalAudioLen + 36;
long longSampleRate = frequency;
int channels = 1;
long byteRate = RECORDER_BPP * frequency * channels/8;
byte[] data = new byte[recBufSize];
try {
in = new FileInputStream(inFilename);
out = new FileOutputStream(outFilename);
totalAudioLen = in.getChannel().size();
totalDataLen = totalAudioLen + 36;
// Why this is don't work?
data = convertStreamToByteArray(in,recBufSize);
byte[] reverseData = reverseByteArray(data);
out.write(reverseData);
WriteWaveFileHeader(out, totalAudioLen, totalDataLen, longSampleRate, channels, byteRate);
in.close();
out.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
// convert InputStream to byte array
public static byte[] convertStreamToByteArray(InputStream is,int size) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[size];
byte[] result = null;
int b;
try {
while ((b = is.read(buffer, 0, buffer.length)) != -1) {
baos.write(buffer, 0, b);
}
result = baos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
baos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return result;
}
// reverse byte array
private byte[] reverseByteArray(byte[] arr) {
int i = 0, j = arr.length-1;
byte tmp;
while(i<j) {
tmp = arr[i];
arr[i] = arr[j];
arr[j] = tmp;
i++;
j--;
}
return arr;
}
// header for wav file`enter code here
private void WriteWaveFileHeader(
FileOutputStream out, long totalAudioLen,
long totalDataLen, long longSampleRate, int channels,
long byteRate) throws IOException {
byte[] header = new byte[44];
header[0] = 'R'; // RIFF/WAVE header
header[1] = 'I';
header[2] = 'F';
header[3] = 'F';
header[4] = (byte) (totalDataLen & 0xff);
header[5] = (byte) ((totalDataLen >> 8) & 0xff);
header[6] = (byte) ((totalDataLen >> 16) & 0xff);
header[7] = (byte) ((totalDataLen >> 24) & 0xff);
header[8] = 'W';
header[9] = 'A';
header[10] = 'V';
header[11] = 'E';
header[12] = 'f'; // 'fmt ' chunk
header[13] = 'm';
header[14] = 't';
header[15] = ' ';
header[16] = 16; // 4 bytes: size of 'fmt ' chunk
header[17] = 0;
header[18] = 0;
header[19] = 0;
header[20] = 1; // format = 1
header[21] = 0;`enter code here`
header[22] = (byte) channels;
header[23] = 0;
header[24] = (byte) (longSampleRate & 0xff);
header[25] = (byte) ((longSampleRate >> 8) & 0xff);
header[26] = (byte) ((longSampleRate >> 16) & 0xff);
header[27] = (byte) ((longSampleRate >> 24) & 0xff);
header[28] = (byte) (byteRate & 0xff);
header[29] = (byte) ((byteRate >> 8) & 0xff);
header[30] = (byte) ((byteRate >> 16) & 0xff);
header[31] = (byte) ((byteRate >> 24) & 0xff);
header[32] = (byte) (1 * 16 / 8); // block align
header[33] = 0;
header[34] = RECORDER_BPP; // bits per sample
header[35] = 0;
header[36] = 'd';
header[37] = 'a';
header[38] = 't';
header[39] = 'a';
header[40] = (byte) (totalAudioLen & 0xff);
header[41] = (byte) ((totalAudioLen >> 8) & 0xff);
header[42] = (byte) ((totalAudioLen >> 16) & 0xff);
header[43] = (byte) ((totalAudioLen >> 24) & 0xff);
out.write(header, 0, 44);
}
這取決於比特率。 但是總的來說,您不能只對字節重新排序。 wave文件具有其邏輯格式,必須保留該邏輯格式才能再次播放該文件。 例如,對於具有16位的PCM編碼的wave文件,我將嘗試反轉16位的塊。 因此,最后16位塊在不重新排列字節的情況下排在最前面。 考慮一下,我懷疑這是否行得通。 必須有一種標頭,必須在開頭保留或重寫該標頭,也許還有一些字節表示音頻數據的結尾。
這應該會有所幫助,但這並不是您想的那么簡單。 波紋波
也許有一個Java庫?
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