RIFF文件由一个简单的表头（header）跟随着多个”chunks”所组。其格式完全跟IFF一样，除整数的存储方式不一样以外。
- 表头（Header）
- 4位组（bytes）：固定为”RIFF”.
- 4位组：little-endian 32-bit正整数，整个文件的大小，扣掉识别字符和长度，共8个字节。
- 4位组：这个文件的类型字符，例如：”AVI “或”WAVE”.
- 接下来是区块（Chunks），每个区块包含：
- 4位组：此区块的ASCII识别字，例如：”fmt “或”data”.
- 4位组：little-endian 32-bit正整数，表示本区块的长度（这个正整数本身和区块识别字的长度不算在内）。
- 不固定长度字段：此区块的资料，大小等同前一栏之正整数。
- 假如区块的长度不为偶数，则填入一个byte。
关于此格式的更多信息，请见互换文件格式（Interchange File Format）条目。
Offset Size Name Description
The canonical WAVE format starts with the RIFF header:
0 4 ChunkID Contains the letters "RIFF" in ASCII form
(0x52494646 big-endian form).
4 4 ChunkSize 36 + SubChunk2Size, or more precisely:
4 + (8 + SubChunk1Size) + (8 + SubChunk2Size)
This is the size of the rest of the chunk
following this number. This is the size of the
entire file in bytes minus 8 bytes for the
two fields not included in this count:
ChunkID and ChunkSize.
8 4 Format Contains the letters "WAVE"
(0x57415645 big-endian form).
The "WAVE" format consists of two subchunks: "fmt " and "data":
The "fmt " subchunk describes the sound data's format:
12 4 Subchunk1ID Contains the letters "fmt "
(0x666d7420 big-endian form).
16 4 Subchunk1Size 16 for PCM. This is the size of the
rest of the Subchunk which follows this number.
20 2 AudioFormat PCM = 1 (i.e. Linear quantization)
Values other than 1 indicate some
form of compression.
22 2 NumChannels Mono = 1, Stereo = 2, etc.
24 4 SampleRate 8000, 44100, etc.
28 4 ByteRate == SampleRate * NumChannels * BitsPerSample/8
32 2 BlockAlign == NumChannels * BitsPerSample/8
The number of bytes for one sample including
all channels. I wonder what happens when
this number isn't an integer?
34 2 BitsPerSample 8 bits = 8, 16 bits = 16, etc.
2 ExtraParamSize if PCM, then doesn't exist
X ExtraParams space for extra parameters
The "data" subchunk contains the size of the data and the actual sound:
36 4 Subchunk2ID Contains the letters "data"
(0x64617461 big-endian form).
40 4 Subchunk2Size == NumSamples * NumChannels * BitsPerSample/8
This is the number of bytes in the data.
You can also think of this as the size
of the read of the subchunk following this
number.
44 * Data The actual sound data.
As an example, here are the opening 72 bytes of a WAVE file with bytes shown as hexadecimal numbers:
52 49 46 46 24 08 00 00 57 41 56 45 66 6d 74 20 10 00 00 00 01 00 02 00
22 56 00 00 88 58 01 00 04 00 10 00 64 61 74 61 00 08 00 00 00 00 00 00
24 17 1e f3 3c 13 3c 14 16 f9 18 f9 34 e7 23 a6 3c f2 24 f2 11 ce 1a 0d
Wave资源
wav音频样本可以从维基百科上(https://en.wikipedia.org/wiki/WAV)下载。
注:少数wav格式不支持
| Format | Bitrate (kbit/s) | 1 minute (KiB) | Sample |
|---|---|---|---|
| 11,025 Hz 16 bit PCM | 176.4 | 1292 | 11k16bitpcm.wav |
| 8,000 Hz 16 bit PCM | 128 | 938 | 8k16bitpcm.wav |
| 11,025 Hz 8 bit PCM | 88.2 | 646 | 11k8bitpcm.wav |
| 11,025 Hz µ-Law | 88.2 | 646 | 11kulaw.wav |
| 8,000 Hz 8 bit PCM | 64 | 469 | 8k8bitpcm.wav |
| 8,000 Hz µ-Law | 64 | 469 | 8kulaw.wav |
| 11,025 Hz 4 bit ADPCM | 44.1 | 323 | 11kadpcm.wav |
| 8,000 Hz 4 bit ADPCM | 32 | 234 | 8kadpcm.wav |
| 11,025 Hz GSM 06.10 | 18 | 132 | 11kgsm.wav |
| 8,000 Hz MP3 16 kbit/s | 16 | 117 | 8kmp316.wav |
| 8,000 Hz GSM 06.10 | 13 | 103 | 8kgsm.wav |
| 8,000 Hz Lernout & Hauspie SBC 12 kbit/s | 12 | 88 | 8ksbc12.wav |
| 8,000 Hz DSP Group Truespeech | 9 | 66 | 8ktruespeech.wav |
| 8,000 Hz MP3 8 kbit/s | 8 | 60 | 8kmp38.wav |
| 8,000 Hz Lernout & Hauspie CELP | 4.8 | 35 | 8kcelp.wav |
DR lib for wav
https://github.com/mackron/dr_libs/blob/master/dr_wav.h
文档信息
- 本文作者：Kiah Zhao
- 本文链接：/2022/03/16/wave/
- 版权声明：自由转载-非商用-非衍生-保持署名（创意共享3.0许可证）
