mirror of https://github.com/Chocobozzz/PeerTube
91 lines
2.5 KiB
TypeScript
91 lines
2.5 KiB
TypeScript
import { CONFIG } from '@server/initializers/config.js'
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import { logger } from '../logger.js'
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export function computeOutputFPS (options: {
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inputFPS: number
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isOriginResolution: boolean
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resolution: number
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type: 'vod' | 'live'
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}) {
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const { resolution, isOriginResolution, type } = options
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const settings = type === 'vod'
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? buildTranscodingFPSOptions(CONFIG.TRANSCODING.FPS.MAX)
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: buildTranscodingFPSOptions(CONFIG.LIVE.TRANSCODING.FPS.MAX)
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let fps = options.inputFPS
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if (
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// On small/medium transcoded resolutions, limit FPS
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!isOriginResolution &&
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resolution !== undefined &&
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resolution < settings.KEEP_ORIGIN_FPS_RESOLUTION_MIN &&
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fps > settings.AVERAGE
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) {
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// Get closest standard framerate by modulo: downsampling has to be done to a divisor of the nominal fps value
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fps = getClosestFramerate({ fps, settings, type: 'STANDARD' })
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}
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if (fps < settings.HARD_MIN) {
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throw new Error(`Cannot compute FPS because ${fps} is lower than our minimum value ${settings.HARD_MIN}`)
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}
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// Cap min FPS
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fps = Math.max(fps, settings.TRANSCODED_MIN)
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// Cap max FPS
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if (fps > settings.TRANSCODED_MAX) {
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fps = getClosestFramerate({ fps, settings, type: 'HD_STANDARD' })
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}
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logger.debug(`Computed output FPS ${fps} for resolution ${resolution}p`, { options, settings })
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return fps
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}
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// ---------------------------------------------------------------------------
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// Private
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// ---------------------------------------------------------------------------
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function buildTranscodingFPSOptions (maxFPS: number) {
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const STANDARD = [ 24, 25, 30 ].filter(v => v <= maxFPS)
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if (STANDARD.length === 0) STANDARD.push(maxFPS)
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const HD_STANDARD = [ 50, 60, maxFPS ].filter(v => v <= maxFPS)
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return {
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HARD_MIN: 0.1,
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TRANSCODED_MIN: 1,
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TRANSCODED_MAX: maxFPS,
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STANDARD,
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HD_STANDARD,
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AVERAGE: Math.min(30, maxFPS),
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KEEP_ORIGIN_FPS_RESOLUTION_MIN: 720 // We keep the original FPS on high resolutions (720 minimum)
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}
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}
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function getClosestFramerate (options: {
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fps: number
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settings: ReturnType<typeof buildTranscodingFPSOptions>
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type: Extract<keyof ReturnType<typeof buildTranscodingFPSOptions>, 'HD_STANDARD' | 'STANDARD'>
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}) {
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const { fps, settings, type } = options
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const copy = [ ...settings[type] ]
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// Biggest FPS first
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const descSorted = copy.sort((a, b) => b - a)
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// Find biggest FPS that can be divided by input FPS
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const found = descSorted.find(e => fps % e === 0)
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if (found) return found
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// Approximation to the best result
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return copy.sort((a, b) => fps % a - fps % b)[0]
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}
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