Go WAVE PCM sound file format

The wave file format is part of Microsoft's riff specification for storing multimedia. A riff file starts with a file header and then a series of data blocks. A wave file is often made up of only one wave block, which contains a format-formatted FMT block and a data block that stores the sampled information.

Standard wave file format

Offset	Length (bytes)	Variable name	Describe	Note
0	4	Chunkid	ASCII character "RIFF", big-endian form	Riff Head
4	4	ChunkSize	36+subchunk2size, i.e.: 4 + (8 + subchunk1size) + (8 + subchunk2size), refers to the number of bytes after the first 8 bytes of the file	Riff Head
8	4	Format	ASCII character "WAVE", big-endian form	Riff Head
12	4	Subchunk1id	ASCII character "FMT", big-endian form	FMT Sub-block
16	4	Subchunk1size	For PCM files is 16. Refers to the FMT block size except the first 8 bytes	FMT Sub-block
20	2	Audioformat	Pcm=1, other values are compressed in some way (see table 2)	FMT Sub-block
22	2	Numchannels	Mono = 1, stereo =2	FMT Sub-block
24	4	Samplerate	Sampling rate, take 16000	FMT Sub-block
28	4	Byterate	Samplerate * Numchannels * BITSPERSAMPLE/8	FMT Sub-block
32	2	Blockalign	Numchannels * bitspersample/8, Total bytes of one sample data in all channels	FMT Sub-block
34	2	BitsPerSample	8 or 16	FMT Sub-block
36	4	Subchunk2id	ASCII string "Data"	Data sub-block
40	4	Subchunk2size	NumSamples * Numchannels * BITSPERSAMPLE/8, refers to the number of bytes in the data	Data sub-block
44	*	Data	The actual sound data

Table 2 Format Code encoding

Format encoding	preprocessing symbols	Data
0x0001	Wave_format_pcm	Pcm
0x0003	Wave_format_ieee_float	Ieee float
0x0006	Wave_format_alaw	8bits ITU-T G.711 A-law
0x0007	Wave_format_mulaw	8-bit ITU-T G.711 U-law
0xFFFE	Wave_format_extensible

Attention:

1) wave file default byte order is the small end order, if the big-endian order with RIFX instead of riff logo

2) The sampled data must be even bytes

3) 8-bit sampling data is stored as an unsigned number, from 0 to 255.16 bits of sampled data is stored as a complement, from 32768 to 32767

4) There may be additional sub-blocks in the wave data stream. Each sub-block has char subchunkid[4],unsigned long subchunksize and subchunksize bytes of data

5) Riff represents resource interchange File Format

Transferred from: http://blog.csdn.net/foxwit/article/details/5802389

Go WAVE PCM sound file format