libqrv is a node module that is used to encode data into video streams. Specifically it does this by transforming data into QR codes, and stitching the multiple frames together into a single video file.
Example
By running the yarn.lock file in the examples directory through convertFile, the video below is produced.
$ yarn install libqrv
convertFile( existingFile [, newFilePath] , cb )
Converts a file into a mp4 video stream of QR codes that contain the base64 encoded data. If newFilePath is not specified .mp4 is added to the file path passed in.
const { convertFile } = require( "libqrv" );
convertFile( "./some/file.txt", "./another/location/output.mp4", ( err ) => {
// err is null unless there is an error
if( err ){
return console.log( "Couldn't convert the file.. " + err );
}
// "./another/location/output.mp4" exists
} );const { convertFile } = require( "libqrv" );
convertFile( "./some/file.txt", ( err ) => {
if( err ){
return console.log( "Couldn't convert the file.. " + err );
}
// if err is not null, and no newFIlePath has been specified
// existingFile + ".mp4" is assumed.
// "./some/file.txt.mp4" exists
} );The LibQRV library itself provides some customization. There are a lot of opportunities that exist to expose more configuration, and functionality.
Usage
const { LibQRV } = require( "libqrv" );
const config = {
debug: true
};
new LibQRV( config, ( err, libqrv ) => {
// libqrv can be used here
libqrv.on( "readableStreamComplete", ( details ) => {
/*
details = {
filename: "yarn.lock",
outputPath: "/var/folders/qr/z123...../T/tmp-..../yarn.lock.mp4"
}
*/
// Let's ensure that we clean up any resources
libqrv.destroy( ( err ) => {
if( err ){
console.log( "Couldn't clean up resources: " + err );
return;
}
console.log( "Cleaned up resources. Goodbye." );
} );
} );
libqrv.queueReadableStream( fs.createReadStream( "./yarn.lock" ), ( err ) => {
if( err ){
console.log( "Couldn't queue readable stream: " + err );
return;
}
// Readable stream has been queued.
// When complete "readableStreamComplete" will be emitted.
} );
} );Default Options
{
"debug": false,
"outputDirectory": "/tmp/tmp-34.........", // geneated by tmp
"qr": {
"width": 240,
"scale": 1,
"margin": 0,
"errorCorrectionLevel": "low"
},
"video": {
"output": {
"framerate": 25
},
"input": {
"framerate": 1
}
}
}
Options to constructor
| Option Name | Default Value | Description |
|---|---|---|
outputDirectory |
Dynamically Generated ( uses tmp ) |
The directory where the output .mp4 will be placed. |
debug |
false |
Whether or not to emit debug events |
qr |
See QR Options | Configuration that relates to QR Code generation |
video |
See Video Options | Configuration that relates to the video generation |
QR Options
| Option Name | Default Value | Description |
|---|---|---|
width |
240 |
The width of the QR code frame that is generated |
scale |
1 |
The number of pixels that are used per "block" to make up the QR code |
margin |
0 |
The amount of blank space that is kept around the QR code. Synonymous with HTML padding |
errorCorrectionLevel |
"low" |
How much error correction is used in the QR code. |
Video Options
| Option Name | Default Value | Description |
|---|---|---|
input.framerate |
1 |
The framerate relating to the QR code images. Per second |
output.framerate |
25 |
The output .mp4 video framerate. Per second |
Constructor
LibQRV uses a configuration object that is passed into the constructor. Additionally, the constructor takes a callback that is called with cb( err, instance ) where err should be null, and instance is the newly created instance of LibQRV.
If you find this module or repository useful, please consider making a pull request to it.
$ yarn run test
yarn run v1.3.2
$ ./node_modules/mocha/bin/mocha -t 60000
Base
✓ LibQRV is a function
Validations
✓ Fails if an invalid config is passed in
Basic operation
✓ Constructor returns sane object in callback
✓ Emits a 'readableStreamComplete' event when finished encoding a readable stream. (8492ms)
convertFile operation
✓ Works when we specify a filename (10250ms)
✓ Works when we don't specify a filename (8534ms)
6 passing (27s)
✨ Done in 28.27s.
MIT