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