114 lines
2.9 KiB
TypeScript
114 lines
2.9 KiB
TypeScript
import { VideoResolution } from '@shared/models'
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type BitPerPixel = { [ id in VideoResolution ]: number }
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// https://bitmovin.com/video-bitrate-streaming-hls-dash/
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const minLimitBitPerPixel: BitPerPixel = {
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[VideoResolution.H_NOVIDEO]: 0,
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[VideoResolution.H_144P]: 0.02,
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[VideoResolution.H_240P]: 0.02,
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[VideoResolution.H_360P]: 0.02,
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[VideoResolution.H_480P]: 0.02,
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[VideoResolution.H_720P]: 0.02,
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[VideoResolution.H_1080P]: 0.02,
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[VideoResolution.H_1440P]: 0.02,
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[VideoResolution.H_4K]: 0.02
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}
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const averageBitPerPixel: BitPerPixel = {
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[VideoResolution.H_NOVIDEO]: 0,
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[VideoResolution.H_144P]: 0.19,
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[VideoResolution.H_240P]: 0.17,
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[VideoResolution.H_360P]: 0.15,
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[VideoResolution.H_480P]: 0.12,
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[VideoResolution.H_720P]: 0.11,
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[VideoResolution.H_1080P]: 0.10,
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[VideoResolution.H_1440P]: 0.09,
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[VideoResolution.H_4K]: 0.08
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}
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const maxBitPerPixel: BitPerPixel = {
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[VideoResolution.H_NOVIDEO]: 0,
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[VideoResolution.H_144P]: 0.32,
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[VideoResolution.H_240P]: 0.29,
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[VideoResolution.H_360P]: 0.26,
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[VideoResolution.H_480P]: 0.22,
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[VideoResolution.H_720P]: 0.19,
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[VideoResolution.H_1080P]: 0.17,
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[VideoResolution.H_1440P]: 0.16,
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[VideoResolution.H_4K]: 0.14
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}
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function getAverageTheoreticalBitrate (options: {
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resolution: VideoResolution
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ratio: number
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fps: number
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}) {
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const targetBitrate = calculateBitrate({ ...options, bitPerPixel: averageBitPerPixel })
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if (!targetBitrate) return 192 * 1000
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return targetBitrate
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}
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function getMaxTheoreticalBitrate (options: {
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resolution: VideoResolution
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ratio: number
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fps: number
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}) {
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const targetBitrate = calculateBitrate({ ...options, bitPerPixel: maxBitPerPixel })
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if (!targetBitrate) return 256 * 1000
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return targetBitrate
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}
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function getMinTheoreticalBitrate (options: {
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resolution: VideoResolution
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ratio: number
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fps: number
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}) {
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const minLimitBitrate = calculateBitrate({ ...options, bitPerPixel: minLimitBitPerPixel })
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if (!minLimitBitrate) return 10 * 1000
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return minLimitBitrate
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}
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// ---------------------------------------------------------------------------
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export {
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getAverageTheoreticalBitrate,
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getMaxTheoreticalBitrate,
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getMinTheoreticalBitrate
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}
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// ---------------------------------------------------------------------------
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function calculateBitrate (options: {
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bitPerPixel: BitPerPixel
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resolution: VideoResolution
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ratio: number
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fps: number
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}) {
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const { bitPerPixel, resolution, ratio, fps } = options
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const resolutionsOrder = [
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VideoResolution.H_4K,
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VideoResolution.H_1440P,
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VideoResolution.H_1080P,
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VideoResolution.H_720P,
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VideoResolution.H_480P,
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VideoResolution.H_360P,
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VideoResolution.H_240P,
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VideoResolution.H_144P,
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VideoResolution.H_NOVIDEO
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]
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for (const toTestResolution of resolutionsOrder) {
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if (toTestResolution <= resolution) {
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return Math.floor(resolution * resolution * ratio * fps * bitPerPixel[toTestResolution])
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}
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}
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throw new Error('Unknown resolution ' + resolution)
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}
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