PeerTube/server/core/helpers/ffmpeg/framerate.ts

44 lines
1.3 KiB
TypeScript

import { VIDEO_TRANSCODING_FPS } from '@server/initializers/constants.js'
export function computeOutputFPS (options: {
inputFPS: number
resolution: number
}) {
const { resolution } = options
let fps = options.inputFPS
if (
// On small/medium resolutions, limit FPS
resolution !== undefined &&
resolution < VIDEO_TRANSCODING_FPS.KEEP_ORIGIN_FPS_RESOLUTION_MIN &&
fps > VIDEO_TRANSCODING_FPS.AVERAGE
) {
// Get closest standard framerate by modulo: downsampling has to be done to a divisor of the nominal fps value
fps = getClosestFramerateStandard({ fps, type: 'STANDARD' })
}
// Hard FPS limits
if (fps > VIDEO_TRANSCODING_FPS.MAX) fps = getClosestFramerateStandard({ fps, type: 'HD_STANDARD' })
if (fps < VIDEO_TRANSCODING_FPS.MIN) {
throw new Error(`Cannot compute FPS because ${fps} is lower than our minimum value ${VIDEO_TRANSCODING_FPS.MIN}`)
}
return fps
}
// ---------------------------------------------------------------------------
// Private
// ---------------------------------------------------------------------------
function getClosestFramerateStandard (options: {
fps: number
type: 'HD_STANDARD' | 'STANDARD'
}) {
const { fps, type } = options
return VIDEO_TRANSCODING_FPS[type].slice(0)
.sort((a, b) => fps % a - fps % b)[0]
}