與n音訊

Question

我一直在使用n音訊過去數天混合兩種波形文件用這種格式混合的WaveStream第二：8000

我發現從https://naudio.codeplex.com/discussions/251475，首先我應該將它們轉換成32位ieeefloatingpoint編碼，然後將轉換後的流添加到WaveMixerStream32。之後，我應該使用Wave32To16Stream將混合數據轉換爲16位/採樣流，將獲得的流轉換爲單聲道並最終將單聲道16位/採樣轉換爲單聲道8位/採樣。

我按照我解釋寫這些代碼行：

WaveFileReader r1 = new WaveFileReader(...); 
    WaveFileReader r2 = new WaveFileReader(...); 

    WaveFormat OutputWaveFormat = WaveFormat.CreateCustomFormat(WaveFormatEncoding.Pcm, 8000, 1, 16000, 2, 16); 
    WaveFormat InputWaveFormat = WaveFormat.CreateALawFormat(8000, 1); 

    WaveFormatConversionStream ConversionStream1 = new WaveFormatConversionStream(OutputWaveFormat, r1); 
    WaveFormatConversionStream ConversionStream2 = new WaveFormatConversionStream(OutputWaveFormat, r2); 

    WaveChannel32 WaveChannel32_1 = new WaveChannel32(ConversionStream1); 
    WaveChannel32 WaveChannel32_2 = new WaveChannel32(ConversionStream2); 

    WaveMixerStream32 mixer32 = new WaveMixerStream32(); 
    mixer32.AddInputStream(WaveChannel32_1); 

    mixer32.AddInputStream(WaveChannel32_2);//(*) 

    Wave32To16Stream stereo16 = new Wave32To16Stream(mixer32); 
    StereoToMonoProvider16 mono16 = new StereoToMonoProvider16(m_Wave32To16Stream); 

線（*）後我有一個流，例如：0 0 32 60 0 0 32 60 0 0 59 126 0 0 59 126 ... 但應用Wave32To16Stream後，我有一個在立體聲16只有一個序列，因此在mono16！ 這一步應該怎麼做？

Answer 1

答案是非常簡單的比我想象的。我只需要將ALaw轉換爲PCM，然後添加兩個波形流，我使用G711 codeproject文章中的ALawDecoder完成。

r1 = new WaveFileReader(...); 
r2 = new WaveFileReader(...); 
r1.Read(arr1, 0, arr1.Length);  
r2.Read(arr2, 0, arr2.Length); 
short[] firstPCM16 = ALawDecoder.ALawDecode(arr1); 
short[] secondPCM16 = ALawDecoder.ALawDecode(arr2); 
byte[] result1 = new byte[firstPCM16.Length * sizeof(short)]; 
byte[] result1 = new byte[secondPCM16.Length * sizeof(short)]; 
Buffer.BlockCopy(firstPCM16, 0, result1, 0, result1.Length); 
Buffer.BlockCopy(secondPCM16, 0, result2, 0, result2.Length); 
for (...) 
{       
    mixed[i] = (byte)(result1[i] + result2[i]);//No need to dividing by 2 because r1 and r2 are 8 bit ALaw and return value of ALawDecoder is 16 bit pcm 
}