JavaScript implementation of SMPTE timecode type
npm install smpte-timecodesmpte-timecode is a JavaScript library for operations with SMPTE timecodes.
- usable in browser and Node environments;
- supports drop-frame and non-drop-frame codes;
- instantiate timecodes from frame count, string time code or JavaScript Date() objects;
- timecode arithmetics: adding frame counts and other timecodes;
- support of implicit conversiont to string (toString()) and number (valueOf());
``javascript`
const Timecode = require('smpte-timecode')
var t = Timecode('00:15:10;03');
t.add('00:02:30;00');
console.log(t.frameCount);
t.subtract(100); //frames
console.log(t.toString());
javascript
Timecode = function (timecode, frameRate, dropFrame) {...};
`-
: number, string or Date
- Numbers are interpreted as frame count.
- Strings are expected as "HH:MM:SS:FF" (non-drop-frame) or
"HH:MM:SS;FF" (drop-frame). The constructor will throw if the string contains invalid timecode, for example frame count above framerate or 0 frames in a drop-frame second.
- If Date() is passed, it is converted to the timecode a master
clock would have with a given framerate. Month, date and
year discarded.-
frameRate: number (frames per second) or Array ([numerator,denominator]), optional
- if a non-integer number is passed that is near 24, 30 or 60, (i.e. 23.97 or 29.97 for example) the fractional 24000/1001, 30000/1001 or 60000/1001 rates will be assumed.
- If an array is passed, the framerate is assumed to be a natural fraction, with first element the numerator and second the denominator (for example, [60000,1001]).
- 30000/1001 (29.97) is assumed if the parameter is omitted.-
dropFrame: boolean, optional
whether the timecode is using drop-frame or non-drop-frame mode.
If omitted, and timecode is a string, the drop-frame mode is determined based on
the ":" or ";" characters separating the frames in the timecode parameter.
If timecode parameter is not a string, drop-frame assumed for 29.97 and 59.94 framerates, non-drop-frame for all others.Examples:
`javascript
var minute = new Timecode('00:01:00:00');
var eightHundredFrames = new Timecode(800,29.97,true);
var nineHundredFrames = new Timecode(900,[60000,1001],true);
var wallClock = new Timecode(new Date());
`Note: a direct call to
returns a Timecode object too, so both direct
calls and instantiating with new return the same result:
`javascript
console.log((new Timecode('00:15:00;00')).toString());
// is the same as
console.log(Timecode('00:15:00;00').toString());
`Using Timecode() Objects
Once a
object is created, the following member variables are available:-
frameCount: number, total number of frames
- frameRate: number, framerate in FPS
- hours: number
- minutes: number
- seconds: number
- frames: number
- dropFrame: boolean, whether timecode is drop-frame or notThe
Timecode object also provides the following member functions:-
add(x): Timecode, adds x to timecode, x can be a number, Date or Timecode
- : Timecode, subtracts x from timecode, x can be a number, Date
or Timecode
- : string, returns the timecode in "HH:MM:SS:FF" or "HH:MM:SS;FF" format
- toString('field'): string, returns the timecode in VITC format, where timecodes above 30fps are represented as frame.field, i.e. HH:MM:SS:FF.f
- toDate(): date, returns a Date object using today's date and timecode as wall clock
- valueOf(): number, returns this.frameCountFor more usage examples, see the unit tests.
Running Tests
To run tests, make sure you run npm ci
The tests can be run in Node using:
npm test
npm run coverage
To run the tests in a browser environment, open the
file
in a browser.Update History
- 1.3.6
- fix for #42 - 59.94 and 29.97 non-drop-frame timecodes would not initialize properly
- 1.3.5
- packaging fix
- 1.3.4
- fix for #37 - support for framerates above 100
- 1.3.3
- fix for #36 - 23.976 is never a drop frame timecode.
- 1.3.2
- fixed to browser-based tests, documentation.
- 1.3.1
- Coverage tests changed to nyc
- Support for fractional framerates and framerates above 60fps
- 1.2.3
- Fix for adding a string-based timecode to already initialized timecode with original framerate (@tommilburn)
- A couple of other date conversion issues (@nkurdybakha & @74ls04)
- 1.2.1
- Added support for 23.976 fps framerate (@funkelodeon)
- 1.2.0
- Added support for 59.94 fps drop-frame expressed without fields - i.e. 00:00:00;59 is 1 frame short of a second;
- Added .ToString('field')` output in HH:MM:SS;FF.f format;Copyright © 2023 LTN Global Communications, Inc. http://www.ltnglobal.com
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