我有一個Active wave錄制wave-file.wav發(fā)生在Source文件夾中.
我需要使用新名稱wave-file-copy.wav將此文件復(fù)制到Destination文件夾.

錄制和復(fù)制應(yīng)該并行進(jìn)行.
我已經(jīng)實現(xiàn)了一個預(yù)定的作業(yè),它將每10分鐘運(yùn)行一次,并將源文件復(fù)制到目標(biāo).

private static void CopyWaveFile(string destinationFile, string sourceFile){
        using (var fs = File.Open(sourceFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)){
            using (var reader = new WaveFileReader(fs)){
                using (var writer = new WaveFileWriter(destinationFile, reader.WaveFormat)){
                    reader.Position = 0;
                    var endPos = (int)reader.Length;
                    var buffer = new byte[1024];
                    while (reader.Position < endPos){
                        var bytesRequired = (int)(endPos - reader.Position);
                        if (bytesRequired <= 0) continue;
                        var bytesToRead = Math.Min(bytesRequired, buffer.Length);
                        var bytesRead = reader.Read(buffer, 0, bytesToRead);
                        if (bytesRead > 0){
                            writer.Write(buffer, 0, bytesRead);
                        }
                    }
                }
            }
        }
    }

即使源文件正在不斷更新,復(fù)制操作也能正常工作.

復(fù)制操作所花費的時間在線性時間內(nèi)增加,因為我每次都復(fù)制整個文件.

我正在嘗試實現(xiàn)一個新函數(shù)ConcatenateWavFiles(),它應(yīng)該使用最新的源記錄字節(jié)來更新目標(biāo)文件的內(nèi)容.

我嘗試過幾個示例代碼 – 我使用的方法是：

>讀取目標(biāo)文件元信息,并獲取長度.
>將目標(biāo)文件的長度設(shè)置為reader.源文件waveReader的位置
>從位置開始讀取源文件直到結(jié)束.

public static void ConcatenateWavFiles(string destinationFile, string sourceFile){  

    WaveFileWriter waveFileWriter = null;
    var sourceReadOffset = GetWaveFileSize(destinationFile);

    try{
        using (var fs = File.Open(sourceFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
        {
            using (var reader = new WaveFileReader(fs))
            {
                waveFileWriter = new WaveFileWriter(destinationFile, reader.WaveFormat);
                if (!reader.WaveFormat.Equals(waveFileWriter.WaveFormat)){
                    throw new InvalidOperationException(
                        "Can't append WAV Files that don't share the same format");
                }

                var startPos = sourceReadOffset - sourceReadOffset % reader.WaveFormat.BlockAlign;
                var endPos = (int) reader.Length;
                reader.Position = startPos;
                var bytesRequired = (int)(endPos - reader.Position);
                var buffer = new byte[bytesRequired];
                if (bytesRequired > 0)
                {
                    var bytesToRead = Math.Min(bytesRequired, buffer.Length);
                    var bytesRead = reader.Read(buffer, 0, bytesToRead);

                    if (bytesRead > 0)
                    {
                        waveFileWriter.Write(buffer, startPos, bytesRead);
                    }
                }
            }
        }
    }
    finally{
        if (waveFileWriter != null){
            waveFileWriter.Dispose();
        }
    }
}

我能夠獲得新內(nèi)容.

是否可以將最新內(nèi)容附加到現(xiàn)有目標(biāo)文件？

如果可能,我在代碼中做錯了什么？

我的代碼拋出以下異常 – 偏移量和長度超出數(shù)組的范圍或計數(shù)大于從索引到源集合末尾的元素數(shù).

解決方法:

我找不到使用NAudio Library進(jìn)行波形音頻文件復(fù)制的解決方案.

但我已經(jīng)使用C#MemoryStreams和FileStreams實現(xiàn)了一個解決方案.

>如果目標(biāo)文件不存在,則將源文件復(fù)制到目標(biāo).
>將所有最新字節(jié)(在上次操作后記錄)附加到目標(biāo)文件.
>修改Wave File Header以反映最后添加的字節(jié). (否則文件的持續(xù)時間不會更新,只會增加文件大小.
>定期重復(fù)此追加操作.

public void ReplicateFile(string destinationFile, string sourceFile){

    if (!Directory.Exists(GetRoutePathFromFile(sourceFile)))
        return;           

    if (!File.Exists(sourceFile))                
        return;           

    if (Directory.Exists(GetRoutePathFromFile(destinationFile))){
        if (File.Exists(destinationFile)){                                         
            UpdateLatestWaveFileContent(destinationFile, sourceFile);
        }else{                 
            CopyWaveFile(destinationFile, sourceFile);
        }
    }else{                        
        Directory.CreateDirectory(GetRoutePathFromFile(destinationFile));
        CopyWaveFile(destinationFile, sourceFile);
    }
}




private static string GetRoutePathFromFile(string file){
    var rootPath = Directory.GetParent(file);
    return rootPath.FullName;
}





private static void CopyWaveFile(string destination, string source){
    var sourceMemoryStream = new MemoryStream();
    using (var fs = File.Open(source, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)){
        fs.CopyTo(sourceMemoryStream);
    }            
    using (var fs = new FileStream(destination, FileMode.CreateNew, FileAccess.ReadWrite, FileShare.ReadWrite)){
        sourceMemoryStream.WriteTo(fs);               
    }
}




private static void UpdateLatestWaveFileContent(string destinationFile, string sourceFile){
    var sourceMemoryStream = new MemoryStream();
    long offset = 0;

    using (var fs = File.Open(destinationFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)){
        offset = fs.Length;
    }

    using (var fs = File.Open(sourceFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)){
        fs.CopyTo(sourceMemoryStream);
    }

    var length = sourceMemoryStream.Length - offset;            

    var buffer = sourceMemoryStream.GetBuffer();
    using (var fs = new FileStream(destinationFile, FileMode.Append, FileAccess.Write, FileShare.ReadWrite)){                
        fs.Write(buffer, (int)offset, (int)length);
    }


    var bytes = new byte[45];

    for (var i = 0; i < 45; i  ){
        bytes[i] = buffer[i];
    }

    ModifyHeaderDataLength(destinationFile, 0, bytes);
}



private static void ModifyHeaderDataLength(string filename, int position, byte[] data){
    using (Stream stream = File.Open(filename, FileMode.OpenOrCreate, FileAccess.Write, FileShare.ReadWrite))
    {
        stream.Position = position;
        stream.Write(data, 0, data.Length);
    }
}