使用Javazoom修剪wav文件的方法有時可以運行

Question

我正在研究一種將wav文件修剪成由用戶進行的選擇的方法。基本思想是使用Javazoom的WaveFile類來編寫一個wav文件，該文件僅包含用戶所做選擇中的聲音數據。問題是，我編寫的代碼完美地工作大約一半的時間，另一半時間它產生靜態。它似乎工作，並不在相同的情況下工作。 wav文件在另一個時間被MediaPlayer加載，並作爲其他方法的輸入流。這是問題的可能來源嗎？我試圖小心關閉流並釋放MediaPlayer，但仍然存在相同的問題。

public void TrimToSelection(double startTime, double endTime){ // Time in seconds 
    InputStream wavStream = null; // InputStream to stream the wav to trim 
    File trimmedSample = null; // File to contain the trimmed down sample 
    File sampleFile = new File(samplePath); // File pointer to the current wav sample 

    // If the sample file exists, try to trim it 
    if (sampleFile.isFile()){ 
     trimmedSample = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC), "trimmedSample.wav"); 
     if (trimmedSample.isFile()) trimmedSample.delete(); // Delete if already exists 

     // Trim the sample down and write it to file 
     try { 
      wavStream = new BufferedInputStream(new FileInputStream(sampleFile)); 
      // Javazoom class WaveFile is used to write the wav 
      WaveFile waveFile = new WaveFile(); 
      waveFile.OpenForWrite(trimmedSample.getAbsolutePath(), (int)audioFormat.getSampleRate(), (short)audioFormat.getSampleSizeInBits(), (short)audioFormat.getChannels()); 
      // The number of bytes of wav data to trim off the beginning 
      long startOffset = (long)(startTime * audioFormat.getSampleSizeInBits() * audioFormat.getSampleRate()/4); 
      // The number of bytes to copy 
      long length = (long)(endTime * audioFormat.getSampleSizeInBits() * audioFormat.getSampleRate()/4) - startOffset; 
      wavStream.skip(44); // Skip the header 
      wavStream.skip(startOffset); 
      byte[] buffer = new byte[1024 * 16]; 
      int bufferLength; 
      for (long i = startOffset; i < length + startOffset; i += buffer.length){ 
       bufferLength = wavStream.read(buffer); 
       short[] shorts = new short[buffer.length/2]; 
       ByteBuffer.wrap(buffer).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shorts); 
       waveFile.WriteData(shorts, shorts.length); 
      } 
      waveFile.Close(); // Complete writing the wave file 
      wavStream.close(); // Close the input stream 
     } catch (IOException e) {e.printStackTrace();} 
     finally { 
      try {if (wavStream != null) wavStream.close();} catch (IOException e){} 
     } 
    } 
    // Delete the original wav sample 
    sampleFile.delete(); 
    // Copy the trimmed wav over to replace the sample 
    trimmedSample.renameTo(sampleFile); 
} 

更新：我改變long startOffset = (long)(startTime * audioFormat.getSampleSizeInBits() * audioFormat.getSampleRate()/4);到long startOffset = ((long)startTime * audioFormat.getSampleSizeInBits() * (long)audioFormat.getSampleRate()/4);同樣地，對於length。出於某種原因改變演員陣容似乎已經解決了靜態問題（我認爲），儘管我不知道爲什麼。現在，我認爲我需要調整緩衝區循環，因爲樣本的末端被切斷。

Answer 1

我不確定問題的根源，但這可能會幫助您弄清楚：RingDroid是一個開源的鈴聲創作者。它有一個內置的波形編輯器。我曾經下載過它，並使用波形編輯器（並對其進行了定製）以獲得有趣的項目。這可能會幫助你到達需要去的地方。請享用。

Answer 2

我的更新中的問題是，startTime長時間拋棄到最近的秒鐘。下面的代碼工作，但我仍然不確定爲什麼我原來的投射方法不起作用。

public void TrimToSelection(double startTime, double endTime){ 
    InputStream wavStream = null; // InputStream to stream the wav to trim 
    File trimmedSample = null; // File to contain the trimmed down sample 
    File sampleFile = new File(samplePath); // File pointer to the current wav sample 

    // If the sample file exists, try to trim it 
    if (sampleFile.isFile()){ 
     trimmedSample = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC), "trimmedSample.wav"); 
     if (trimmedSample.isFile()) trimmedSample.delete(); 

     // Trim the sample down and write it to file 
     try { 
      wavStream = new BufferedInputStream(new FileInputStream(sampleFile)); 
      // Javazoom WaveFile class is used to write the wav 
      WaveFile waveFile = new WaveFile(); 
      waveFile.OpenForWrite(trimmedSample.getAbsolutePath(), (int)audioFormat.getSampleRate(), (short)audioFormat.getSampleSizeInBits(), (short)audioFormat.getChannels()); 
      // The number of bytes of wav data to trim off the beginning 
      long startOffset = (long)(startTime * audioFormat.getSampleRate()) * audioFormat.getSampleSizeInBits()/4; 
      // The number of bytes to copy 
      long length = ((long)(endTime * audioFormat.getSampleRate()) * audioFormat.getSampleSizeInBits()/4) - startOffset; 
      wavStream.skip(44); // Skip the header 
      wavStream.skip(startOffset); 
      byte[] buffer = new byte[1024]; 
      int i = 0; 
      while (i < length){ 
       if (length - i >= buffer.length) { 
        wavStream.read(buffer); 
       } 
       else { // Write the remaining number of bytes 
        buffer = new byte[(int)length - i]; 
        wavStream.read(buffer); 
       } 
       short[] shorts = new short[buffer.length/2]; 
       ByteBuffer.wrap(buffer).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shorts); 
       waveFile.WriteData(shorts, shorts.length); 
       i += buffer.length; 
      } 
      waveFile.Close(); // Complete writing the wave file 
      wavStream.close(); // Close the input stream 
     } catch (IOException e) {e.printStackTrace();} 
     finally { 
      try {if (wavStream != null) wavStream.close();} catch (IOException e){} 
     } 
    } 
}