PeerTube/server/helpers/ffmpeg-utils.ts

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import * as ffmpeg from 'fluent-ffmpeg'
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import { readFile, remove, writeFile } from 'fs-extra'
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import { dirname, join } from 'path'
import { VideoFileMetadata } from '@shared/models/videos/video-file-metadata'
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import { getMaxBitrate, getTargetBitrate, VideoResolution } from '../../shared/models/videos'
import { checkFFmpegEncoders } from '../initializers/checker-before-init'
import { CONFIG } from '../initializers/config'
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import { FFMPEG_NICE, VIDEO_LIVE, VIDEO_TRANSCODING_FPS } from '../initializers/constants'
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import { processImage } from './image-utils'
import { logger } from './logger'
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/**
* A toolbox to play with audio
*/
namespace audio {
export const get = (videoPath: string) => {
// without position, ffprobe considers the last input only
// we make it consider the first input only
// if you pass a file path to pos, then ffprobe acts on that file directly
return new Promise<{ absolutePath: string, audioStream?: any }>((res, rej) => {
function parseFfprobe (err: any, data: ffmpeg.FfprobeData) {
if (err) return rej(err)
if ('streams' in data) {
const audioStream = data.streams.find(stream => stream['codec_type'] === 'audio')
if (audioStream) {
return res({
absolutePath: data.format.filename,
audioStream
})
}
}
return res({ absolutePath: data.format.filename })
}
return ffmpeg.ffprobe(videoPath, parseFfprobe)
})
}
export namespace bitrate {
const baseKbitrate = 384
const toBits = (kbits: number) => kbits * 8000
export const aac = (bitrate: number): number => {
switch (true) {
case bitrate > toBits(baseKbitrate):
return baseKbitrate
default:
return -1 // we interpret it as a signal to copy the audio stream as is
}
}
export const mp3 = (bitrate: number): number => {
/*
a 192kbit/sec mp3 doesn't hold as much information as a 192kbit/sec aac.
That's why, when using aac, we can go to lower kbit/sec. The equivalences
made here are not made to be accurate, especially with good mp3 encoders.
*/
switch (true) {
case bitrate <= toBits(192):
return 128
case bitrate <= toBits(384):
return 256
default:
return baseKbitrate
}
}
}
}
function computeResolutionsToTranscode (videoFileResolution: number, type: 'vod' | 'live') {
const configResolutions = type === 'vod'
? CONFIG.TRANSCODING.RESOLUTIONS
: CONFIG.LIVE.TRANSCODING.RESOLUTIONS
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const resolutionsEnabled: number[] = []
// Put in the order we want to proceed jobs
const resolutions = [
VideoResolution.H_NOVIDEO,
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VideoResolution.H_480P,
VideoResolution.H_360P,
VideoResolution.H_720P,
VideoResolution.H_240P,
VideoResolution.H_1080P,
VideoResolution.H_4K
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]
for (const resolution of resolutions) {
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if (configResolutions[resolution + 'p'] === true && videoFileResolution > resolution) {
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resolutionsEnabled.push(resolution)
}
}
return resolutionsEnabled
}
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async function getVideoStreamSize (path: string) {
const videoStream = await getVideoStreamFromFile(path)
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return videoStream === null
? { width: 0, height: 0 }
: { width: videoStream.width, height: videoStream.height }
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}
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async function getVideoStreamCodec (path: string) {
const videoStream = await getVideoStreamFromFile(path)
if (!videoStream) return ''
const videoCodec = videoStream.codec_tag_string
const baseProfileMatrix = {
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High: '6400',
Main: '4D40',
Baseline: '42E0'
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}
let baseProfile = baseProfileMatrix[videoStream.profile]
if (!baseProfile) {
logger.warn('Cannot get video profile codec of %s.', path, { videoStream })
baseProfile = baseProfileMatrix['High'] // Fallback
}
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let level = videoStream.level.toString(16)
if (level.length === 1) level = `0${level}`
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return `${videoCodec}.${baseProfile}${level}`
}
async function getAudioStreamCodec (path: string) {
const { audioStream } = await audio.get(path)
if (!audioStream) return ''
const audioCodec = audioStream.codec_name
if (audioCodec === 'aac') return 'mp4a.40.2'
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logger.warn('Cannot get audio codec of %s.', path, { audioStream })
return 'mp4a.40.2' // Fallback
}
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async function getVideoFileResolution (path: string) {
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const size = await getVideoStreamSize(path)
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return {
videoFileResolution: Math.min(size.height, size.width),
isPortraitMode: size.height > size.width
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}
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}
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async function getVideoFileFPS (path: string) {
const videoStream = await getVideoStreamFromFile(path)
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if (videoStream === null) return 0
for (const key of [ 'avg_frame_rate', 'r_frame_rate' ]) {
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const valuesText: string = videoStream[key]
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if (!valuesText) continue
const [ frames, seconds ] = valuesText.split('/')
if (!frames || !seconds) continue
const result = parseInt(frames, 10) / parseInt(seconds, 10)
if (result > 0) return Math.round(result)
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}
return 0
}
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async function getMetadataFromFile <T> (path: string, cb = metadata => metadata) {
return new Promise<T>((res, rej) => {
ffmpeg.ffprobe(path, (err, metadata) => {
if (err) return rej(err)
return res(cb(new VideoFileMetadata(metadata)))
})
})
}
async function getVideoFileBitrate (path: string) {
return getMetadataFromFile<number>(path, metadata => metadata.format.bit_rate)
}
function getDurationFromVideoFile (path: string) {
return getMetadataFromFile<number>(path, metadata => Math.floor(metadata.format.duration))
}
function getVideoStreamFromFile (path: string) {
return getMetadataFromFile<any>(path, metadata => metadata.streams.find(s => s.codec_type === 'video') || null)
}
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async function generateImageFromVideoFile (fromPath: string, folder: string, imageName: string, size: { width: number, height: number }) {
const pendingImageName = 'pending-' + imageName
const options = {
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filename: pendingImageName,
count: 1,
folder
}
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const pendingImagePath = join(folder, pendingImageName)
try {
await new Promise<string>((res, rej) => {
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ffmpeg(fromPath, { niceness: FFMPEG_NICE.THUMBNAIL })
.on('error', rej)
.on('end', () => res(imageName))
.thumbnail(options)
})
const destination = join(folder, imageName)
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await processImage(pendingImagePath, destination, size)
} catch (err) {
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logger.error('Cannot generate image from video %s.', fromPath, { err })
try {
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await remove(pendingImagePath)
} catch (err) {
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logger.debug('Cannot remove pending image path after generation error.', { err })
}
}
}
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type TranscodeOptionsType = 'hls' | 'quick-transcode' | 'video' | 'merge-audio' | 'only-audio'
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interface BaseTranscodeOptions {
type: TranscodeOptionsType
inputPath: string
outputPath: string
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resolution: VideoResolution
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isPortraitMode?: boolean
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}
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interface HLSTranscodeOptions extends BaseTranscodeOptions {
type: 'hls'
copyCodecs: boolean
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hlsPlaylist: {
videoFilename: string
}
}
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interface QuickTranscodeOptions extends BaseTranscodeOptions {
type: 'quick-transcode'
}
interface VideoTranscodeOptions extends BaseTranscodeOptions {
type: 'video'
}
interface MergeAudioTranscodeOptions extends BaseTranscodeOptions {
type: 'merge-audio'
audioPath: string
}
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interface OnlyAudioTranscodeOptions extends BaseTranscodeOptions {
type: 'only-audio'
}
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type TranscodeOptions =
HLSTranscodeOptions
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| VideoTranscodeOptions
| MergeAudioTranscodeOptions
| OnlyAudioTranscodeOptions
| QuickTranscodeOptions
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function transcode (options: TranscodeOptions) {
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return new Promise<void>(async (res, rej) => {
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try {
let command = getFFmpeg(options.inputPath)
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.output(options.outputPath)
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if (options.type === 'quick-transcode') {
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command = buildQuickTranscodeCommand(command)
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} else if (options.type === 'hls') {
command = await buildHLSVODCommand(command, options)
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} else if (options.type === 'merge-audio') {
command = await buildAudioMergeCommand(command, options)
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} else if (options.type === 'only-audio') {
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command = buildOnlyAudioCommand(command, options)
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} else {
command = await buildx264Command(command, options)
}
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command
.on('error', (err, stdout, stderr) => {
logger.error('Error in transcoding job.', { stdout, stderr })
return rej(err)
})
.on('end', () => {
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return fixHLSPlaylistIfNeeded(options)
.then(() => res())
.catch(err => rej(err))
})
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.run()
} catch (err) {
return rej(err)
}
})
}
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async function canDoQuickTranscode (path: string): Promise<boolean> {
// NOTE: This could be optimized by running ffprobe only once (but it runs fast anyway)
const videoStream = await getVideoStreamFromFile(path)
const parsedAudio = await audio.get(path)
const fps = await getVideoFileFPS(path)
const bitRate = await getVideoFileBitrate(path)
const resolution = await getVideoFileResolution(path)
// check video params
if (videoStream == null) return false
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if (videoStream['codec_name'] !== 'h264') return false
if (videoStream['pix_fmt'] !== 'yuv420p') return false
if (fps < VIDEO_TRANSCODING_FPS.MIN || fps > VIDEO_TRANSCODING_FPS.MAX) return false
if (bitRate > getMaxBitrate(resolution.videoFileResolution, fps, VIDEO_TRANSCODING_FPS)) return false
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// check audio params (if audio stream exists)
if (parsedAudio.audioStream) {
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if (parsedAudio.audioStream['codec_name'] !== 'aac') return false
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const maxAudioBitrate = audio.bitrate['aac'](parsedAudio.audioStream['bit_rate'])
if (maxAudioBitrate !== -1 && parsedAudio.audioStream['bit_rate'] > maxAudioBitrate) return false
}
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return true
}
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function getClosestFramerateStandard (fps: number, type: 'HD_STANDARD' | 'STANDARD'): number {
return VIDEO_TRANSCODING_FPS[type].slice(0)
.sort((a, b) => fps % a - fps % b)[0]
}
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function convertWebPToJPG (path: string, destination: string): Promise<void> {
return new Promise<void>(async (res, rej) => {
try {
const command = ffmpeg(path).output(destination)
command.on('error', (err, stdout, stderr) => {
logger.error('Error in ffmpeg webp convert process.', { stdout, stderr })
return rej(err)
})
.on('end', () => res())
.run()
} catch (err) {
return rej(err)
}
})
}
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function runLiveTranscoding (rtmpUrl: string, outPath: string, resolutions: number[], fps, deleteSegments: boolean) {
const command = getFFmpeg(rtmpUrl)
command.inputOption('-fflags nobuffer')
const varStreamMap: string[] = []
command.complexFilter([
{
inputs: '[v:0]',
filter: 'split',
options: resolutions.length,
outputs: resolutions.map(r => `vtemp${r}`)
},
...resolutions.map(r => ({
inputs: `vtemp${r}`,
filter: 'scale',
options: `w=-2:h=${r}`,
outputs: `vout${r}`
}))
])
command.outputOption('-b_strategy 1')
command.outputOption('-bf 16')
command.outputOption('-preset superfast')
command.outputOption('-level 3.1')
command.outputOption('-map_metadata -1')
command.outputOption('-pix_fmt yuv420p')
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command.outputOption('-max_muxing_queue_size 1024')
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command.outputOption('-g ' + (fps * 2))
for (let i = 0; i < resolutions.length; i++) {
const resolution = resolutions[i]
command.outputOption(`-map [vout${resolution}]`)
command.outputOption(`-c:v:${i} libx264`)
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command.outputOption(`-b:v:${i} ${getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS)}`)
command.outputOption(`-map a:0`)
command.outputOption(`-c:a:${i} aac`)
varStreamMap.push(`v:${i},a:${i}`)
}
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addDefaultLiveHLSParams(command, outPath, deleteSegments)
command.outputOption('-var_stream_map', varStreamMap.join(' '))
command.run()
return command
}
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function runLiveMuxing (rtmpUrl: string, outPath: string, deleteSegments: boolean) {
const command = getFFmpeg(rtmpUrl)
command.inputOption('-fflags nobuffer')
command.outputOption('-c:v copy')
command.outputOption('-c:a copy')
command.outputOption('-map 0:a?')
command.outputOption('-map 0:v?')
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addDefaultLiveHLSParams(command, outPath, deleteSegments)
command.run()
return command
}
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async function hlsPlaylistToFragmentedMP4 (hlsDirectory: string, segmentFiles: string[], outputPath: string) {
const concatFilePath = join(hlsDirectory, 'concat.txt')
function cleaner () {
remove(concatFilePath)
.catch(err => logger.error('Cannot remove concat file in %s.', hlsDirectory, { err }))
}
// First concat the ts files to a mp4 file
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const content = segmentFiles.map(f => 'file ' + f)
.join('\n')
await writeFile(concatFilePath, content + '\n')
const command = getFFmpeg(concatFilePath)
command.inputOption('-safe 0')
command.inputOption('-f concat')
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command.outputOption('-c:v copy')
command.audioFilter('aresample=async=1:first_pts=0')
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command.output(outputPath)
return runCommand(command, cleaner)
}
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async function runCommand (command: ffmpeg.FfmpegCommand, onEnd?: Function) {
command.run()
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return new Promise<string>((res, rej) => {
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command.on('error', err => {
if (onEnd) onEnd()
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rej(err)
})
command.on('end', () => {
if (onEnd) onEnd()
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res()
})
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})
}
// ---------------------------------------------------------------------------
export {
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getVideoStreamCodec,
getAudioStreamCodec,
runLiveMuxing,
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convertWebPToJPG,
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getVideoStreamSize,
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getVideoFileResolution,
getMetadataFromFile,
getDurationFromVideoFile,
runLiveTranscoding,
generateImageFromVideoFile,
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TranscodeOptions,
TranscodeOptionsType,
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transcode,
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getVideoFileFPS,
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computeResolutionsToTranscode,
audio,
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hlsPlaylistToFragmentedMP4,
getVideoFileBitrate,
canDoQuickTranscode
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}
// ---------------------------------------------------------------------------
function addDefaultX264Params (command: ffmpeg.FfmpegCommand) {
command.outputOption('-level 3.1') // 3.1 is the minimal resource allocation for our highest supported resolution
.outputOption('-b_strategy 1') // NOTE: b-strategy 1 - heuristic algorithm, 16 is optimal B-frames for it
.outputOption('-bf 16') // NOTE: Why 16: https://github.com/Chocobozzz/PeerTube/pull/774. b-strategy 2 -> B-frames<16
.outputOption('-pix_fmt yuv420p') // allows import of source material with incompatible pixel formats (e.g. MJPEG video)
.outputOption('-map_metadata -1') // strip all metadata
}
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function addDefaultLiveHLSParams (command: ffmpeg.FfmpegCommand, outPath: string, deleteSegments: boolean) {
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command.outputOption('-hls_time ' + VIDEO_LIVE.SEGMENT_TIME_SECONDS)
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command.outputOption('-hls_list_size ' + VIDEO_LIVE.SEGMENTS_LIST_SIZE)
if (deleteSegments === true) {
command.outputOption('-hls_flags delete_segments')
}
command.outputOption(`-hls_segment_filename ${join(outPath, '%v-%04d.ts')}`)
command.outputOption('-master_pl_name master.m3u8')
command.outputOption(`-f hls`)
command.output(join(outPath, '%v.m3u8'))
}
async function buildx264Command (command: ffmpeg.FfmpegCommand, options: TranscodeOptions) {
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let fps = await getVideoFileFPS(options.inputPath)
if (
// On small/medium resolutions, limit FPS
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options.resolution !== undefined &&
options.resolution < VIDEO_TRANSCODING_FPS.KEEP_ORIGIN_FPS_RESOLUTION_MIN &&
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fps > VIDEO_TRANSCODING_FPS.AVERAGE
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) {
// Get closest standard framerate by modulo: downsampling has to be done to a divisor of the nominal fps value
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fps = getClosestFramerateStandard(fps, 'STANDARD')
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}
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command = await presetH264(command, options.inputPath, options.resolution, fps)
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if (options.resolution !== undefined) {
// '?x720' or '720x?' for example
const size = options.isPortraitMode === true ? `${options.resolution}x?` : `?x${options.resolution}`
command = command.size(size)
}
if (fps) {
// Hard FPS limits
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if (fps > VIDEO_TRANSCODING_FPS.MAX) fps = getClosestFramerateStandard(fps, 'HD_STANDARD')
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else if (fps < VIDEO_TRANSCODING_FPS.MIN) fps = VIDEO_TRANSCODING_FPS.MIN
command = command.withFPS(fps)
}
return command
}
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async function buildAudioMergeCommand (command: ffmpeg.FfmpegCommand, options: MergeAudioTranscodeOptions) {
command = command.loop(undefined)
command = await presetH264VeryFast(command, options.audioPath, options.resolution)
command = command.input(options.audioPath)
.videoFilter('scale=trunc(iw/2)*2:trunc(ih/2)*2') // Avoid "height not divisible by 2" error
.outputOption('-tune stillimage')
.outputOption('-shortest')
return command
}
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function buildOnlyAudioCommand (command: ffmpeg.FfmpegCommand, options: OnlyAudioTranscodeOptions) {
command = presetOnlyAudio(command)
return command
}
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function buildQuickTranscodeCommand (command: ffmpeg.FfmpegCommand) {
command = presetCopy(command)
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command = command.outputOption('-map_metadata -1') // strip all metadata
.outputOption('-movflags faststart')
return command
}
async function buildHLSVODCommand (command: ffmpeg.FfmpegCommand, options: HLSTranscodeOptions) {
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const videoPath = getHLSVideoPath(options)
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if (options.copyCodecs) command = presetCopy(command)
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else if (options.resolution === VideoResolution.H_NOVIDEO) command = presetOnlyAudio(command)
else command = await buildx264Command(command, options)
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command = command.outputOption('-hls_time 4')
.outputOption('-hls_list_size 0')
.outputOption('-hls_playlist_type vod')
.outputOption('-hls_segment_filename ' + videoPath)
.outputOption('-hls_segment_type fmp4')
.outputOption('-f hls')
.outputOption('-hls_flags single_file')
return command
}
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function getHLSVideoPath (options: HLSTranscodeOptions) {
return `${dirname(options.outputPath)}/${options.hlsPlaylist.videoFilename}`
}
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async function fixHLSPlaylistIfNeeded (options: TranscodeOptions) {
if (options.type !== 'hls') return
const fileContent = await readFile(options.outputPath)
const videoFileName = options.hlsPlaylist.videoFilename
const videoFilePath = getHLSVideoPath(options)
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// Fix wrong mapping with some ffmpeg versions
const newContent = fileContent.toString()
.replace(`#EXT-X-MAP:URI="${videoFilePath}",`, `#EXT-X-MAP:URI="${videoFileName}",`)
await writeFile(options.outputPath, newContent)
}
/**
* A slightly customised version of the 'veryfast' x264 preset
*
* The veryfast preset is right in the sweet spot of performance
* and quality. Superfast and ultrafast will give you better
* performance, but then quality is noticeably worse.
*/
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async function presetH264VeryFast (command: ffmpeg.FfmpegCommand, input: string, resolution: VideoResolution, fps?: number) {
let localCommand = await presetH264(command, input, resolution, fps)
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localCommand = localCommand.outputOption('-preset:v veryfast')
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/*
MAIN reference: https://slhck.info/video/2017/03/01/rate-control.html
Our target situation is closer to a livestream than a stream,
since we want to reduce as much a possible the encoding burden,
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although not to the point of a livestream where there is a hard
constraint on the frames per second to be encoded.
*/
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return localCommand
}
/**
* Standard profile, with variable bitrate audio and faststart.
*
* As for the audio, quality '5' is the highest and ensures 96-112kbps/channel
* See https://trac.ffmpeg.org/wiki/Encode/AAC#fdk_vbr
*/
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async function presetH264 (command: ffmpeg.FfmpegCommand, input: string, resolution: VideoResolution, fps?: number) {
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let localCommand = command
.format('mp4')
.videoCodec('libx264')
.outputOption('-movflags faststart')
addDefaultX264Params(localCommand)
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const parsedAudio = await audio.get(input)
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if (!parsedAudio.audioStream) {
localCommand = localCommand.noAudio()
} else if ((await checkFFmpegEncoders()).get('libfdk_aac')) { // we favor VBR, if a good AAC encoder is available
localCommand = localCommand
.audioCodec('libfdk_aac')
.audioQuality(5)
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} else {
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// we try to reduce the ceiling bitrate by making rough matches of bitrates
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// of course this is far from perfect, but it might save some space in the end
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localCommand = localCommand.audioCodec('aac')
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const audioCodecName = parsedAudio.audioStream['codec_name']
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if (audio.bitrate[audioCodecName]) {
const bitrate = audio.bitrate[audioCodecName](parsedAudio.audioStream['bit_rate'])
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if (bitrate !== undefined && bitrate !== -1) localCommand = localCommand.audioBitrate(bitrate)
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}
}
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if (fps) {
// Constrained Encoding (VBV)
// https://slhck.info/video/2017/03/01/rate-control.html
// https://trac.ffmpeg.org/wiki/Limiting%20the%20output%20bitrate
const targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS)
localCommand = localCommand.outputOptions([ `-maxrate ${targetBitrate}`, `-bufsize ${targetBitrate * 2}` ])
// Keyframe interval of 2 seconds for faster seeking and resolution switching.
// https://streaminglearningcenter.com/blogs/whats-the-right-keyframe-interval.html
// https://superuser.com/a/908325
localCommand = localCommand.outputOption(`-g ${fps * 2}`)
}
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return localCommand
}
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function presetCopy (command: ffmpeg.FfmpegCommand): ffmpeg.FfmpegCommand {
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return command
.format('mp4')
.videoCodec('copy')
.audioCodec('copy')
}
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function presetOnlyAudio (command: ffmpeg.FfmpegCommand): ffmpeg.FfmpegCommand {
return command
.format('mp4')
.audioCodec('copy')
.noVideo()
}
function getFFmpeg (input: string) {
// We set cwd explicitly because ffmpeg appears to create temporary files when trancoding which fails in read-only file systems
const command = ffmpeg(input, { niceness: FFMPEG_NICE.TRANSCODING, cwd: CONFIG.STORAGE.TMP_DIR })
if (CONFIG.TRANSCODING.THREADS > 0) {
// If we don't set any threads ffmpeg will chose automatically
command.outputOption('-threads ' + CONFIG.TRANSCODING.THREADS)
}
return command
}