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/* eslint-disable no-bitwise */
const ffmpeg = require('fluent-ffmpeg');
const probe = require('ffmpeg-probe');
const noop = () => {};
const getRandomInt = (min, max) => {
const minInt = Math.ceil(min);
const maxInt = Math.floor(max);
// eslint-disable-next-line no-mixed-operators
return Math.floor(Math.random() * (maxInt - minInt + 1) + minInt);
};
const getStartTime = (vDuration, fDuration, ignoreBeforePercent, ignoreAfterPercent) => {
// by subtracting the fragment duration we can be sure that the resulting
// start time + fragment duration will be less than the video duration
const safeVDuration = vDuration - fDuration;
// if the fragment duration is longer than the video duration
if (safeVDuration <= 0) {
return 0;
}
return getRandomInt(ignoreBeforePercent * safeVDuration, ignoreAfterPercent * safeVDuration);
};
module.exports = async opts => {
const {
log = noop,
// general output options
quality = 2,
width,
height,
input,
output,
fragmentDurationSecond = 3,
ignoreBeforePercent = 0.25,
ignoreAfterPercent = 0.75
} = opts;
const info = await probe(input);
let { duration } = info.format;
duration = parseInt(duration, 10);
const startTime = getStartTime(duration, fragmentDurationSecond, ignoreBeforePercent, ignoreAfterPercent);
const result = { startTime, duration };
await new Promise((resolve, reject) => {
let scale = null;
if (width && height) {
result.width = width | 0;
result.height = height | 0;
scale = `scale=${width}:${height}`;
} else if (width) {
result.width = width | 0;
result.height = ((info.height * width) / info.width) | 0;
scale = `scale=${width}:-1`;
} else if (height) {
result.height = height | 0;
result.width = ((info.width * height) / info.height) | 0;
scale = `scale=-1:${height}`;
} else {
result.width = info.width;
result.height = info.height;
}
return ffmpeg()
.input(input)
.inputOptions([`-ss ${startTime}`])
.outputOptions(['-vsync', 'vfr'])
.outputOptions(['-q:v', quality, '-vf', scale])
.outputOptions([`-t ${fragmentDurationSecond}`])
.noAudio()
.output(output)
.on('start', cmd => log && log({ cmd }))
.on('end', resolve)
.on('error', reject)
.run();
});
return result;
};
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