yuv-rx

JavaScript library for reading videos as Rx Observables of decoded frames

Example usage: reading a frame at 0:42, converting to RGB, and encoding it as a base64 encoded PNG image with sharp

``typescript
import {Observable, from, take, map, concatMap} from 'rxjs';
import {toRGBInterleaved, YuvParser} from 'yuv-rx';
const sharp = require('sharp');

const yuvParser = new YuvParser({
ffmpeg: '/usr/local/bin/ffmpeg', // optional path, defaults to 'ffmpeg'
verbose: true
});
yuvParser.read('input.mp4', {
videoStream: 1, // select second video stream of input file
seekSeconds: 42, // skip 42 seconds without decoding
vframes: 1 // only decode 1 frame
}).pipe(
take(1),
map(toRGBInterleaved),
concatMap(frame => {
return from(sharp(frame.colorPlanes.rgb.data, {
raw: {
width: frame.header.width,
height: frame.header.height,
channels: 3,
premultiplied: false
}
}).png().toBuffer().then(b => b.toString('base64')));
})
).subscribe({
next: base64frame => console.log(base64frame)
});
`
Example of usage with custom ffmpeg command line options to find frames with difference at pixel (42,42)
`typescript
import {Observable, from, take, map, concatMap} from 'rxjs';

const yuvParser = new YuvParser({
ffmpeg: '/usr/local/bin/ffmpeg', // optional path, defaults to 'ffmpeg'
verbose: false
});

yuvParser.readCustom([
'-i',
'input1.mp4',
'-i',
'input2.mp4',
'-filter_complex',
'[0:v]format=gray[2];[1:v]format=gray[3];[2][3]blend=all_mode=difference[d];[d]format=yuv420p[v]',
'-map',
'[v]',
]).pipe(
filter(diffFrame => diffFrame.colorPlanes.y.data[42*diffFrame.header.width + 42] > 10),
map(diffFrame => diffFrame.header.fn),
toArray()
).subscribe({
next: frameNumbers => console.log(Frames with difference at pixel (42,42): ${frameNumbers})
});
``

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