|
1
|
|
|
/* |
|
2
|
|
|
* riff |
|
3
|
|
|
* Get the chunks of a RIFF file. |
|
4
|
|
|
* TODO: This should be a npm package on its own. |
|
5
|
|
|
* Copyright (c) 2017 Rafael da Silva Rocha. MIT License. |
|
6
|
|
|
* https://github.com/rochars/wavefile |
|
7
|
|
|
* |
|
8
|
|
|
*/ |
|
9
|
|
|
|
|
10
|
|
|
const byteData = require("byte-data"); |
|
11
|
|
|
|
|
12
|
|
|
/** |
|
13
|
|
|
* Get the chunks of a RIFF file. |
|
14
|
|
|
* @param {Uint8Array|!Array<number>} buffer the RIFF file bytes. |
|
15
|
|
|
* @param {boolean} bigEndian true if its RIFX. |
|
16
|
|
|
* @return {Object} |
|
17
|
|
|
*/ |
|
18
|
|
|
function getChunks(buffer, bigEndian) { |
|
19
|
|
|
return { |
|
20
|
|
|
"chunkId": byteData.fromBytes( |
|
21
|
|
|
buffer.slice(0, 4), 8, {"char": true} |
|
22
|
|
|
), |
|
23
|
|
|
"chunkSize": byteData.fromBytes( |
|
24
|
|
|
buffer.slice(4, 8), 32, {'be': bigEndian} |
|
25
|
|
|
)[0], |
|
26
|
|
|
"format": byteData.fromBytes( |
|
27
|
|
|
buffer.slice(8, 12), 8, {"char": true} |
|
28
|
|
|
), |
|
29
|
|
|
"subChunks": getSubChunks(buffer, bigEndian) |
|
30
|
|
|
} |
|
31
|
|
|
} |
|
32
|
|
|
|
|
33
|
|
|
/** |
|
34
|
|
|
* List the sub chunks of a RIFF file. |
|
35
|
|
|
* @param {Uint8Array|!Array<number>} buffer the RIFF file bytes. |
|
36
|
|
|
* @param {boolean} bigEndian true if its RIFX. |
|
37
|
|
|
* @return {Object} |
|
38
|
|
|
*/ |
|
39
|
|
|
function getSubChunks(buffer, bigEndian) { |
|
40
|
|
|
let chunks = []; |
|
41
|
|
|
let len = buffer.length; |
|
42
|
|
|
let i = 12; |
|
43
|
|
|
let subChunkSize; |
|
44
|
|
|
while(i < len) { |
|
45
|
|
|
subChunkSize = byteData.fromBytes( |
|
46
|
|
|
buffer.slice(i + 4, i + 8), 32, {'be': bigEndian})[0]; |
|
47
|
|
|
chunks.push({ |
|
48
|
|
|
"subChunkId": byteData.fromBytes(buffer.slice(i, i + 4), 8, {"char": true}), |
|
49
|
|
|
"subChunkSize": subChunkSize, |
|
50
|
|
|
"subChunkData": buffer.slice(i + 8, i + 8 + subChunkSize) |
|
51
|
|
|
}); |
|
52
|
|
|
i = i + 8 + subChunkSize; |
|
53
|
|
|
} |
|
54
|
|
|
return chunks; |
|
55
|
|
|
} |
|
56
|
|
|
|
|
57
|
|
|
module.exports.getChunks = getChunks; |
|
58
|
|
|
|
rochars /
wavefile
