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https://github.com/gka/canvid
tiny js library for playing video on canvas elements (without audio)
https://github.com/gka/canvid
Last synced: 4 days ago
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tiny js library for playing video on canvas elements (without audio)
- Host: GitHub
- URL: https://github.com/gka/canvid
- Owner: gka
- License: isc
- Created: 2015-08-06T14:45:48.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2018-09-20T09:33:22.000Z (over 6 years ago)
- Last Synced: 2024-12-22T18:03:10.412Z (11 days ago)
- Language: JavaScript
- Homepage: https://gka.github.io/canvid
- Size: 5.25 MB
- Stars: 1,056
- Watchers: 30
- Forks: 69
- Open Issues: 11
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-canvas - canvid - tiny js library for playing video on canvas elements (without audio)   (Libraries / Audio Video)
README
# canvid.js
[](https://cdnjs.com/libraries/canvid)
**canvid** is a tiny dependency free library for playback of relatively short videos on canvas elements.
* **Why not just use HTML5 video?**
Because ~~you can't~~ until [Oct 2016](https://webkit.org/blog/6784/new-video-policies-for-ios/) you could not embed and autoplay HTML5 videos on iOS! Yeah, [that sucked](https://developer.apple.com/library/safari/documentation/AudioVideo/Conceptual/Using_HTML5_Audio_Video/Device-SpecificConsiderations/Device-SpecificConsiderations.html#//apple_ref/doc/uid/TP40009523-CH5-SW4).
* **Why is this better than using an animated GIF?**
Videos look kind of gross when converted to animated GIFs because of the colors sampling. Also the file size of video GIFs can get pretty huge. GIF is just not made for videos. JPG does a much better job of compressing video frames. Also, animated GIFs don't give you any playback controls. You can't pause a GIF or delay it's playback. With canvid you can do that.
* **Why only "relatively short" videos?**
As you see further down, the container format for canvid is a big image sprite of all the frames of each clip. Sadly, iOS limits the maximum image size (bigger image get sampled down), so that puts a limit on the maximum frames you can store.
* **Why is there no audio?**
canvid doesn't support audio for the same reason animated GIF doesn't support audio either: because that's not what it was built for. (if you need audio, try [iphone-inline-video](https://github.com/bfred-it/iphone-inline-video))
## Installation
**npm**
```
$ npm install --save canvid
```
**git clone**
```
$ git clone [email protected]:gka/canvid.git
```
## Usage
You can use canvid.js with AMD, CommonJS and browser globals.
```js
var canvidControl = canvid({
selector : '.video',
videos: {
clip1: { src: 'clip1.jpg', frames: 38, cols: 6, loops: 1, onEnd: function(){
console.log('clip1 ended.');
canvidControl.play('clip2');
}},
clip2: { src: 'clip2.jpg', frames: 43, cols: 6, fps: 24 }
},
width: 500,
height: 400,
loaded: function() {
canvidControl.play('clip1');
// reverse playback
// canvidControl.play('clip1', true);
}
});
```
If you want to use canvid with [React](https://facebook.github.io/react/) you can check this simple [react + canvid demo](http://codepen.io/moklick/pen/eJgbaL) to see how it works.
## Options
* **videos** required
Video/Sprite objects (videoKey : videoOptions).
* **src** required
Path of the sprite image.
* **frames** required
Number of frames.
* **cols** required
Number of columns.
* **loops** optional
Number of loops.
* **fps** optional (default: 15)
Frames per second.
* **onEnd** optional
Function that gets called when the clip ended.
* **selector** optional
The selector of the element where the video gets displayed. You can also pass a DOM element as a selector.
`default: '.canvid-wrapper'`
* **width** optional
Width of the element where the video gets displayed.
`default: 800`
* **height** optional
Height of the element where the video gets displayed.
`default: 450`
* **loaded** optional
Function that gets called when all videos are loaded.
* **srcGif** optional
Path of the fallback gif, if canvas is not supported.
## Methods
The canvid function returns an object to control the video:
```js
var canvidControl = canvid(canvidOptions);
```
**play**
Plays video of the passed videoKey. The parameters isReverse (default: false) and fps (default: 15) are optional.
```js
canvidControl.play(videoKey [,isReverse, fps]);
```
**pause**
Pause current video.
```js
canvidControl.pause();
```
**resume**
Resume current video.
```js
canvidControl.resume();
```
**destroy**
Stops video and removes the canvas of the current canvid element from the DOM.
```js
canvidControl.destroy();
```
**isPlaying**
Returns true or false whether the video is playing or not.
```js
canvidControl.isPlaying();
```
**getCurrentFrame**
Returns the current frame number.
```js
canvidControl.getCurrentFrame();
```
**setCurrentFrame**
Sets the current frame number.
```js
canvidControl.setCurrentFrame(0);
```
## How to convert your video to a JPG sprite
First, convert you video into single frames using [ffmpeg](https://www.ffmpeg.org/):
```
mkdir frames
ffmpeg -i myvideo.mp4 -vf scale=375:-1 -r 5 frames/%04d.png
```
Then, use ImageMagicks [montage](http://www.imagemagick.org/script/montage.php) to stich all the frames into one big image:
```
montage -border 0 -geometry 375x -tile 6x -quality 60% frames/*.png myvideo.jpg
```
## Is canvid responsive?
Yes it is, thanks to a nice little trick. Regardless of what `width` and `height` parameters you set in the canvid constructor, you can use `style="width:100%"` on the canvas element and it will get scaled to the outer container and preserve its original aspect ratio.
```css
canvas.canvid {
width: 100%;
}
```
## Known Issues
Some users encountered problems on mobile devices with large sprites. A workaround is to split the sprite into multiple sprites.
If you're experiencing problems with `montage` (e.g. "unable to read font") try updating `imagemagick` to the latest version.
## Contributors
* [Gregor Aisch](http://driven-by-data.net)
* [Moritz Klack](http://moritzklack.com)