PCM encapsulation in WAV format

From: http://blog.csdn.net/dahan_wangtao/archive/2010/03/10/5365014.aspx

Recently, we have to re-integrate the IPTV framework. There is a section in the middle that needs to package PCM into a WAV file. Let's take a look at the wav encapsulation instructions and record the key points, hope to help others:

The WAV format mainly includes the following frameworks:

Unsigned char ucwavheader [] =

{

// Riff wave chunk

0x52, 0x49, 0x46, 0x46, // "Riff"

0x30, 0x00, 0x00, 0x00, // = Total file length-8

0x57, 0x41, 0x56, 0x45, // "Wave"

// Format chunk

0x66, 0x6d, 0x74, 0x20, // "FMT"

0x10, 0x00, 0x00, 0x00, // Chunk length, value unchanged

0x01, 0x00, // The encoding method is generally 1 (PCM)

0x01, 0x00, // Number of audio channels

0x80, 0x3e, 0x00, 0x00, // Sampling frequency

0x00, 0x7d, 0x00, 0x00, // Required bytes per second = sampling frequency * block alignment bytes

0x02, 0x00, // Data Alignment bytes = number of bytes (byte) at each sampling point * Number of Audio Channels

0x10, 0x00, // Bit occupied by each sampling point

// Fact chunk

0x66, 0x61, 0x63, 0x74, // The chunk "fact" does not move

0x04, 0x00, 0x00, 0x00, // Block Length

0x00, 0xbe, 0x00, 0x00,

 

// Data chunk

0x64, 0x61, 0x74, 0x61, // "Data"

0x00, 0x00, 0x00, 0x00, // Block length = actual PCM Data Length

}

After reading the above structure, it is not difficult to understand the WAV format! When PCM is encapsulated into WAV, you need to understand the following points:

1: channels. How many channels does PCM data have?

2: sampling frequency. What is the sampling frequency of PCM Data? Generally 44.1 K 16000 8000, etc.

3: How many places each sampling point occupies

With the above data, it can be encapsulated into WAV format.

1: First, write the ucwavheaderdata into the .wav file header,

2: Enter PCM Data

3: Move the file pointer to the position of File Header + 4 and modify the value of the current size again.

After completing the above steps, the PCM data is encapsulated in WAV format!