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peertube/server/helpers/ffmpeg-utils.ts
2019-06-06 14:45:57 +02:00

478 lines
15 KiB
TypeScript

import * as ffmpeg from 'fluent-ffmpeg'
import { dirname, join } from 'path'
import { getTargetBitrate, getMaxBitrate, VideoResolution } from '../../shared/models/videos'
import { FFMPEG_NICE, VIDEO_TRANSCODING_FPS } from '../initializers/constants'
import { processImage } from './image-utils'
import { logger } from './logger'
import { checkFFmpegEncoders } from '../initializers/checker-before-init'
import { readFile, remove, writeFile } from 'fs-extra'
import { CONFIG } from '../initializers/config'
function computeResolutionsToTranscode (videoFileHeight: number) {
const resolutionsEnabled: number[] = []
const configResolutions = CONFIG.TRANSCODING.RESOLUTIONS
// Put in the order we want to proceed jobs
const resolutions = [
VideoResolution.H_480P,
VideoResolution.H_360P,
VideoResolution.H_720P,
VideoResolution.H_240P,
VideoResolution.H_1080P,
VideoResolution.H_4K
]
for (const resolution of resolutions) {
if (configResolutions[ resolution + 'p' ] === true && videoFileHeight > resolution) {
resolutionsEnabled.push(resolution)
}
}
return resolutionsEnabled
}
async function getVideoFileSize (path: string) {
const videoStream = await getVideoStreamFromFile(path)
return {
width: videoStream.width,
height: videoStream.height
}
}
async function getVideoFileResolution (path: string) {
const size = await getVideoFileSize(path)
return {
videoFileResolution: Math.min(size.height, size.width),
isPortraitMode: size.height > size.width
}
}
async function getVideoFileFPS (path: string) {
const videoStream = await getVideoStreamFromFile(path)
for (const key of [ 'avg_frame_rate', 'r_frame_rate' ]) {
const valuesText: string = videoStream[key]
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)
}
return 0
}
async function getVideoFileBitrate (path: string) {
return new Promise<number>((res, rej) => {
ffmpeg.ffprobe(path, (err, metadata) => {
if (err) return rej(err)
return res(metadata.format.bit_rate)
})
})
}
function getDurationFromVideoFile (path: string) {
return new Promise<number>((res, rej) => {
ffmpeg.ffprobe(path, (err, metadata) => {
if (err) return rej(err)
return res(Math.floor(metadata.format.duration))
})
})
}
async function generateImageFromVideoFile (fromPath: string, folder: string, imageName: string, size: { width: number, height: number }) {
const pendingImageName = 'pending-' + imageName
const options = {
filename: pendingImageName,
count: 1,
folder
}
const pendingImagePath = join(folder, pendingImageName)
try {
await new Promise<string>((res, rej) => {
ffmpeg(fromPath, { niceness: FFMPEG_NICE.THUMBNAIL })
.on('error', rej)
.on('end', () => res(imageName))
.thumbnail(options)
})
const destination = join(folder, imageName)
await processImage(pendingImagePath, destination, size)
} catch (err) {
logger.error('Cannot generate image from video %s.', fromPath, { err })
try {
await remove(pendingImagePath)
} catch (err) {
logger.debug('Cannot remove pending image path after generation error.', { err })
}
}
}
type TranscodeOptionsType = 'hls' | 'quick-transcode' | 'video' | 'merge-audio'
interface BaseTranscodeOptions {
type: TranscodeOptionsType
inputPath: string
outputPath: string
resolution: VideoResolution
isPortraitMode?: boolean
}
interface HLSTranscodeOptions extends BaseTranscodeOptions {
type: 'hls'
hlsPlaylist: {
videoFilename: string
}
}
interface QuickTranscodeOptions extends BaseTranscodeOptions {
type: 'quick-transcode'
}
interface VideoTranscodeOptions extends BaseTranscodeOptions {
type: 'video'
}
interface MergeAudioTranscodeOptions extends BaseTranscodeOptions {
type: 'merge-audio'
audioPath: string
}
type TranscodeOptions = HLSTranscodeOptions | VideoTranscodeOptions | MergeAudioTranscodeOptions | QuickTranscodeOptions
function transcode (options: TranscodeOptions) {
return new Promise<void>(async (res, rej) => {
try {
let command = ffmpeg(options.inputPath, { niceness: FFMPEG_NICE.TRANSCODING })
.output(options.outputPath)
if (options.type === 'quick-transcode') {
command = await buildQuickTranscodeCommand(command)
} else if (options.type === 'hls') {
command = await buildHLSCommand(command, options)
} else if (options.type === 'merge-audio') {
command = await buildAudioMergeCommand(command, options)
} else {
command = await buildx264Command(command, options)
}
if (CONFIG.TRANSCODING.THREADS > 0) {
// if we don't set any threads ffmpeg will chose automatically
command = command.outputOption('-threads ' + CONFIG.TRANSCODING.THREADS)
}
command
.on('error', (err, stdout, stderr) => {
logger.error('Error in transcoding job.', { stdout, stderr })
return rej(err)
})
.on('end', () => {
return fixHLSPlaylistIfNeeded(options)
.then(() => res())
.catch(err => rej(err))
})
.run()
} catch (err) {
return rej(err)
}
})
}
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[ 'codec_name' ] !== 'h264') 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
// check audio params (if audio stream exists)
if (parsedAudio.audioStream) {
if (parsedAudio.audioStream[ 'codec_name' ] !== 'aac') return false
const maxAudioBitrate = audio.bitrate[ 'aac' ](parsedAudio.audioStream[ 'bit_rate' ])
if (maxAudioBitrate !== -1 && parsedAudio.audioStream[ 'bit_rate' ] > maxAudioBitrate) return false
}
return true
}
// ---------------------------------------------------------------------------
export {
getVideoFileSize,
getVideoFileResolution,
getDurationFromVideoFile,
generateImageFromVideoFile,
TranscodeOptions,
TranscodeOptionsType,
transcode,
getVideoFileFPS,
computeResolutionsToTranscode,
audio,
getVideoFileBitrate,
canDoQuickTranscode
}
// ---------------------------------------------------------------------------
async function buildx264Command (command: ffmpeg.FfmpegCommand, options: VideoTranscodeOptions) {
let fps = await getVideoFileFPS(options.inputPath)
// On small/medium resolutions, limit FPS
if (
options.resolution !== undefined &&
options.resolution < VIDEO_TRANSCODING_FPS.KEEP_ORIGIN_FPS_RESOLUTION_MIN &&
fps > VIDEO_TRANSCODING_FPS.AVERAGE
) {
fps = VIDEO_TRANSCODING_FPS.AVERAGE
}
command = await presetH264(command, options.inputPath, options.resolution, fps)
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
if (fps > VIDEO_TRANSCODING_FPS.MAX) fps = VIDEO_TRANSCODING_FPS.MAX
else if (fps < VIDEO_TRANSCODING_FPS.MIN) fps = VIDEO_TRANSCODING_FPS.MIN
command = command.withFPS(fps)
}
return command
}
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
}
async function buildQuickTranscodeCommand (command: ffmpeg.FfmpegCommand) {
command = await presetCopy(command)
command = command.outputOption('-map_metadata -1') // strip all metadata
.outputOption('-movflags faststart')
return command
}
async function buildHLSCommand (command: ffmpeg.FfmpegCommand, options: HLSTranscodeOptions) {
const videoPath = getHLSVideoPath(options)
command = await presetCopy(command)
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
}
function getHLSVideoPath (options: HLSTranscodeOptions) {
return `${dirname(options.outputPath)}/${options.hlsPlaylist.videoFilename}`
}
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)
// 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)
}
function getVideoStreamFromFile (path: string) {
return new Promise<any>((res, rej) => {
ffmpeg.ffprobe(path, (err, metadata) => {
if (err) return rej(err)
const videoStream = metadata.streams.find(s => s.codec_type === 'video')
if (!videoStream) return rej(new Error('Cannot find video stream of ' + path))
return res(videoStream)
})
})
}
/**
* 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.
*/
async function presetH264VeryFast (command: ffmpeg.FfmpegCommand, input: string, resolution: VideoResolution, fps?: number) {
let localCommand = await presetH264(command, input, resolution, fps)
localCommand = localCommand.outputOption('-preset:v veryfast')
/*
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,
although not to the point of a livestream where there is a hard
constraint on the frames per second to be encoded.
*/
return localCommand
}
/**
* A toolbox to play with audio
*/
namespace audio {
export const get = (option: 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(option, parseFfprobe)
})
}
export namespace bitrate {
const baseKbitrate = 384
const toBits = (kbits: number): number => { return 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
}
}
}
}
/**
* 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
*/
async function presetH264 (command: ffmpeg.FfmpegCommand, input: string, resolution: VideoResolution, fps?: number) {
let localCommand = command
.format('mp4')
.videoCodec('libx264')
.outputOption('-level 3.1') // 3.1 is the minimal ressource allocation for our highest supported resolution
.outputOption('-b_strategy 1') // NOTE: b-strategy 1 - heuristic algorythm, 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
.outputOption('-movflags faststart')
const parsedAudio = await audio.get(input)
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)
} else {
// we try to reduce the ceiling bitrate by making rough matches of bitrates
// of course this is far from perfect, but it might save some space in the end
localCommand = localCommand.audioCodec('aac')
const audioCodecName = parsedAudio.audioStream[ 'codec_name' ]
if (audio.bitrate[ audioCodecName ]) {
const bitrate = audio.bitrate[ audioCodecName ](parsedAudio.audioStream[ 'bit_rate' ])
if (bitrate !== undefined && bitrate !== -1) localCommand = localCommand.audioBitrate(bitrate)
}
}
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}`)
}
return localCommand
}
async function presetCopy (command: ffmpeg.FfmpegCommand): Promise<ffmpeg.FfmpegCommand> {
return command
.format('mp4')
.videoCodec('copy')
.audioCodec('copy')
}