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I have installed Speex Voice ACM Codec 1.0.1.1 codec and they seem to have DIFFERENT .wav header then one described in C# code in this NSpeex(C#) package.

I can read .wav files created with “Speex Voice ACM Codec 1.0.1.1”, and decode them successfully, but when I create .wav files, “Speex Voice ACM Codec 1.0.1.1” does not recognize my header. I checked with Hex editor, and there are some bytes in .wav header that “Speex Voice ACM Codec 1.0.1.1” creates, and I do not create, and they are different then what is in NSpeex.PcmWaveWriter class.

So, I agree with this part: 

raf.Write(WAVE_FORMAT_SPEEX); // Format tag: Speex   
raf.Write((short)channels); // Number of channels    
raf.Write(sampleRate); // Sampling frequency    
raf.Write((CalculateEffectiveBitrate(mode, channels, quality) + 7) >> 3); // Average bytes per second       
raf.Write((short)CalculateBlockSize(mode, channels, quality)); // Blocksize of data    
raf.Write((short)quality); // Bits per sample

But, not with the rest what is in the code of NSpeex.PcmWaveWriter class.

In Hex editor I see (after above mentioned part) this in .wav file created by “Speex Voice ACM Codec 1.0.1.1”: 

//byte[] speexSpecific ={   
//   0x00, 0x01, 0x02, 0x00,0x0a, 0x00,   
//   0x00, 0x00, 0xf4, 0x01,    
//   0x03, 0x00, 0x00, 0x00};

But I do not know what is that and how to create .wav header to be compatible with “Speex Voice ACM Codec 1.0.1.1”. Again, I can decode their .wav files, and create my .wav files that I can decode, but that codec seems to not recognize my .wav header.

Speex is supposed to be “Open source”, can someone reveal the secret bytes in .wav (speex) header?

Mark_55
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1 Answers1

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I found it! This explains exactly 14 bytes I was missing (check SPEEX_WFX_EXTRA_BYTES=14)

//typedef struct tWAVEFORMATEX
//{
//    WORD        wFormatTag;         /* format type */
//    WORD        nChannels;          /* number of channels (i.e. mono, stereo...) */
//    DWORD       nSamplesPerSec;     /* sample rate */
//    DWORD       nAvgBytesPerSec;    /* for buffer estimation */
//    WORD        nBlockAlign;        /* block size of data */
//    WORD        wBitsPerSample;     /* number of bits per sample of mono data */
//    WORD        cbSize;             /* the count in bytes of the size of */
//                                    /* extra information (after cbSize) */
//} WAVEFORMATEX, *PWAVEFORMATEX, NEAR *NPWAVEFORMATEX, FAR *LPWAVEFORMATEX;

//#define WAVE_FORMAT_SPEEX                           0xa109  
//#define SPEEXWAVEFORMAT_VERSION 0x0100    // 1.0 
//#define SPEEX_WFX_EXTRA_BYTES   14 

///* 
//    wfx.wFormatTag = WAVE_FORMAT_SPEEX 
//    wfx.nChannels = 1,2 
//    wfx.nSamplesPerSec = 8000,16000,32000 
//    wfx.nAvgBytesPerSec = ... 
//    wfx.nBlockAlign = CBR? ... : 1 
//    wfx.wBitsPerSample = 16 
//    wfx.cbSize = SPEEX_WFX_EXTRA_BYTES 

//    For VBR: 
//    wfx.nAvgBytesPerSec = SPEEX_BITRATE_24600; 
//*/ 

//typedef struct speexwaveformat_tag 
//{ 
//    WAVEFORMATEX    wfx; 

//    WORD nVersion;        // SPEEXWAVEFORMAT_VERSION 
//    WORD nFramesPerBlock;// 1.. 
//    WORD nQuality;        // 0..10 
//    WORD nMode;           // SPEEX_MODE_... 
//    WORD nVbrQuality; // 0..1000 ,float [0.00 , 10.00] 
//    WORD nComplexity; // 1..10 
//    WORD nFlags;      // SPEEX_FLAG_... 
//} SPEEXWAVEFORMAT;            
// CBR,ABR,VBR 

//#define SPEEX_MODE_CBR            0 
//#define SPEEX_MODE_ABR            1 
//#define SPEEX_MODE_VBR            2 

//// flags 
//#define SPEEX_FLAG_VAD            0x0001 
//#define SPEEX_FLAG_DTX            0x0002 

//#define SPEEX_DEF_QUALITY 3 
//#define SPEEX_DEF_COMPLEXITY 3 
//#define SPEEX_DEF_VBR_QUALITY 500
Mark_55
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