smpte.js


Easily deal with Timecode SMPTE format in js. If you need a PHP lib, check out fireworkweb/smpte.php.

Installation

Using npm or yarn:
``
npm install smpte.js

yarn add smpte.js
`

Usage

$3


Using ES6 sintax:
`javascript
import SMPTE from 'smpte.js';

SMPTE.defaults.frameRate = 29.97;
SMPTE.defaults.dropFrame = true;

let timecode = new SMPTE(1);
let timecodeToAdd = new SMPTE('00;00;00;02');
let anotherTimecodeToAdd = SMPTE.fromSeconds(1);

console.log(
timecode
.add(timecodeToAdd)
.add(anotherTimecodeToAdd)
.toString('00:00:00;00')
);
// 00:00:01;03

let invalidTm = new SMPTE('00:01:00:23', 24, true);
// Error: Only 29.97 frame rate has drop frame support

let invalidTm = new SMPTE('00:01:00:59', 60, false);
// Error: Frame rate not supported

let invalidTm = new SMPTE(-1440, 24, false);
// Error: Negative frames not supported

let invalidTm = new SMPTE('00:00:00:24', 24, false);
// Error: Invalid timecode
`

$3

SMPTE objects can be instatianted from frame count, date object, seconds, timecode integer parts or directly from timecode string.

`javascript
// Frame count
let tm = SMPTE.fromFrames(1440, 24, false);

// Date object
let tm = SMPTE.fromDate(Date.now(), 24, false);

// Seconds
let tm = SMPTE.fromSeconds(60, 24, false);

// Timecode integer parts
let tm = SMPTE.fromParts(0, 1, 0, 0, 24, false);

// Timecode string
let tm = SMPTE.fromTimecode('00:01:00:00', 24, false);

// or using the constructor
let tm = new SMPTE('00:01:00:00', 24, false);
`

$3

SMPTE objects provide the following properties once an object is instantiated:

| Property | Type | get | set | Description |
| ---------------------- | --------- | ------------------ | ------------------ | ---------------------------- |
| frameCount | Number | :white_check_mark: | :white_check_mark: | Total number of frames |
| hours | Number | :white_check_mark: | :white_check_mark: | Hours number |
| minutes | Number | :white_check_mark: | :white_check_mark: | Minutes number |
| seconds | Number | :white_check_mark: | :white_check_mark: | Seconds number |
| frames | Number | :white_check_mark: | :white_check_mark: | Frames number |
| durationInSeconds | Number | :white_check_mark: | :x: | Timecode duration in seconds |
| attributes.df | Boolean | :white_check_mark: | :white_check_mark: | Global drop frame indicator |
| attributes.frameRate | Number | :white_check_mark: | :white_check_mark: | Global Frame rate in FPS |

$3

Each SMPTE object provides the following methods:

#### addFromSeconds(seconds)
Adds a number of seconds to the current timecode object.
* seconds: Number indicating the seconds to be added.
* return: Reference to the changed SMPTE object

##### Example:
`javascript
let tc = SMPTE.fromSeconds(2, 24, false);
console.log(tc.addFromSeconds(2).toString())
// 00:00:04:00
`

#### subtractFromSeconds(seconds)
Substracts a timecode or a frame count from the current SMPTE object.
* seconds: Number indicating the seconds to be subtracted.
* return: Reference to the changed SMPTE object

##### Example:
`javascript
let tc = SMPTE.fromSeconds(2, 24, false);
console.log(tc.subtractFromSeconds(2).toString())
// 00:00:00:00
`

#### add(time, operation = 1)
Adds a timecode or a frame count to the current SMPTE object.
* time: Number|String|SMPTE indicating the value to be added.
* operation: Number used to get the sign of the time.
* return: Reference to the changed SMPTE object

##### Example:
`javascript
let tc = SMPTE.fromTimecode('00:01:00:00', 24, false);
console.log(tc.add('00:00:30:00').toString())
// 00:01:30:00
`

#### subtract(time)
Substracts a timecode or a frame count from the current SMPTE object.
* time: Number|String|SMPTE indicating the value to be subtracted.
* return: Reference to the altered SMPTE object

##### Example:
`javascript
let tc = SMPTE.fromTimecode('00:00:01:00', 24, false);
console.log(tc.subtract(4).toString())
// 00:00:00:20
`

#### toString(format = undefined)
Returns a string with the SMPTE timecode representation.
* format: String mask to form the string.
* return: Timecode string.

##### Example:
`javascript
console.log(new SMPTE(48, 24, false).toString())
// 00:00:02:00
`

#### toDate()
Converts a SMPTE object to a date object.
* return: Respective Date object.
`javascript
console.log(new SMPTE(48, 24, false).toDate().getSeconds())
// 2
`

#### isTimecodeFormatValid(timecode, df) - static
Checks if a timecode string is in a valid format.
* timecode: String to be evaluated.
* df: Boolean indicating if is drop frame representation.
* return: Boolean.
`javascript
console.log(SMPTE.isTimecodeFormatValid('24:59:59:29', false));
// false
console.log(SMPTE.isTimecodeFormatValid('23:59:59:29', false));
// true

console.log(SMPTE.isTimecodeFormatValid('24:59:59:29', true));
// false
console.log(SMPTE.isTimecodeFormatValid('24:59:59;29', true));
// true
`

#### isValidTimecode(timecode, fr = defaults.frameRate, df = defaults.dropFrame) - static
Checks if a timecode is valid according to SMPTE standard.
* timecode: String to be evaluated.
* fr: Number indicating the frame rate.
* df: Boolean indicating if is drop frame representation.
* return: Boolean.
`javascript
console.log(SMPTE.isValidTimecode('23:59:59:24', 24, false));
// false
console.log(SMPTE.isValidTimecode('23:59:59:23', 24, false));
// true
`

#### frameCountFromTimecode(timecode, fr = defaults.frameRate, df = defaults.dropFrame) - static
Gets the frame count given a timecode string.
* timecode: String timecode.
* fr: Number indicating the frame rate.
* df: Boolean indicating if is drop frame representation.
* return: Number.
`javascript
console.log(SMPTE.frameCountFromTimecode('00:01:00;02', 29.97, true))
// 1800
console.log(SMPTE.frameCountFromTimecode('00:01:00:00', 29.97, false))
// 1800
`

#### isFramerateSupported(framerate) - static
Checks if a frame rate is supported.
* framerate: Number indicating the frame rate.
* return: Boolean.
`javascript
console.log(SMPTE.isFramerateSupported(59.94))
// false
console.log(SMPTE.isFramerateSupported(25))
// true
`

$3


You can easily change the default value accessing the static default object from the SMPTE class and change the frameRate or the dropFrame property.

`javascript
import SMPTE from 'smpte.js';

SMPTE.defaults.frameRate = 29.97;
SMPTE.defaults.dropFrame = true;
``

Contributing

All contribution is welcome, please feel free to open tickets and pull requests.

License

MIT.