45 lines
1.4 KiB
TypeScript
45 lines
1.4 KiB
TypeScript
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import { VIDEO_TRANSCODING_FPS } from '@server/initializers/constants'
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import { VideoResolution } from '@shared/models'
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export function computeOutputFPS (options: {
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inputFPS: number
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resolution: VideoResolution
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}) {
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const { resolution } = options
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let fps = options.inputFPS
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if (
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// On small/medium resolutions, limit FPS
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resolution !== undefined &&
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resolution < VIDEO_TRANSCODING_FPS.KEEP_ORIGIN_FPS_RESOLUTION_MIN &&
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fps > VIDEO_TRANSCODING_FPS.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 = getClosestFramerateStandard({ fps, type: 'STANDARD' })
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}
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// Hard FPS limits
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if (fps > VIDEO_TRANSCODING_FPS.MAX) fps = getClosestFramerateStandard({ fps, type: 'HD_STANDARD' })
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if (fps < VIDEO_TRANSCODING_FPS.MIN) {
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throw new Error(`Cannot compute FPS because ${fps} is lower than our minimum value ${VIDEO_TRANSCODING_FPS.MIN}`)
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}
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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 getClosestFramerateStandard (options: {
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fps: number
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type: 'HD_STANDARD' | 'STANDARD'
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}) {
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const { fps, type } = options
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return VIDEO_TRANSCODING_FPS[type].slice(0)
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.sort((a, b) => fps % a - fps % b)[0]
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}
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