import { logger } from '@server/helpers/logger'
import { AvailableEncoders, EncoderOptionsBuilder, getTargetBitrate, VideoResolution } from '../../../shared/models/videos'
import { buildStreamSuffix, resetSupportedEncoders } from '../../helpers/ffmpeg-utils'
import { canDoQuickAudioTranscode, ffprobePromise, getAudioStream, getMaxAudioBitrate } from '../../helpers/ffprobe-utils'
import { VIDEO_TRANSCODING_FPS } from '../../initializers/constants'
/**
*
* Available encoders and profiles for the transcoding jobs
* These functions are used by ffmpeg-utils that will get the encoders and options depending on the chosen profile
*
*/
// Resources:
// * https://slhck.info/video/2017/03/01/rate-control.html
// * https://trac.ffmpeg.org/wiki/Limiting%20the%20output%20bitrate
const defaultX264VODOptionsBuilder: EncoderOptionsBuilder = async ({ inputBitrate, resolution, fps }) => {
const targetBitrate = buildTargetBitrate({ inputBitrate, resolution, fps })
if (!targetBitrate) return { outputOptions: [ ] }
return {
outputOptions: [
`-preset veryfast`,
`-r ${fps}`,
`-maxrate ${targetBitrate}`,
`-bufsize ${targetBitrate * 2}`
]
}
}
const defaultX264LiveOptionsBuilder: EncoderOptionsBuilder = async ({ resolution, fps, inputBitrate, streamNum }) => {
const targetBitrate = buildTargetBitrate({ inputBitrate, resolution, fps })
return {
outputOptions: [
`-preset veryfast`,
`${buildStreamSuffix('-r:v', streamNum)} ${fps}`,
`${buildStreamSuffix('-b:v', streamNum)} ${targetBitrate}`,
`-maxrate ${targetBitrate}`,
`-bufsize ${targetBitrate * 2}`
]
}
}
const defaultAACOptionsBuilder: EncoderOptionsBuilder = async ({ input, streamNum }) => {
const probe = await ffprobePromise(input)
if (await canDoQuickAudioTranscode(input, probe)) {
logger.debug('Copy audio stream %s by AAC encoder.', input)
return { copy: true, outputOptions: [ ] }
}
const parsedAudio = await getAudioStream(input, probe)
// 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
const audioCodecName = parsedAudio.audioStream['codec_name']
const bitrate = getMaxAudioBitrate(audioCodecName, parsedAudio.bitrate)
logger.debug('Calculating audio bitrate of %s by AAC encoder.', input, { bitrate: parsedAudio.bitrate, audioCodecName })
if (bitrate !== undefined && bitrate !== -1) {
return { outputOptions: [ buildStreamSuffix('-b:a', streamNum), bitrate + 'k' ] }
}
return { outputOptions: [ ] }
}
const defaultLibFDKAACVODOptionsBuilder: EncoderOptionsBuilder = ({ streamNum }) => {
return { outputOptions: [ buildStreamSuffix('-q:a', streamNum), '5' ] }
}
// Used to get and update available encoders
class VideoTranscodingProfilesManager {
private static instance: VideoTranscodingProfilesManager
// 1 === less priority
private readonly encodersPriorities = {
vod: this.buildDefaultEncodersPriorities(),
live: this.buildDefaultEncodersPriorities()
}
private readonly availableEncoders = {
vod: {
libx264: {
default: defaultX264VODOptionsBuilder
},
aac: {
default: defaultAACOptionsBuilder
},
libfdk_aac: {
default: defaultLibFDKAACVODOptionsBuilder
}
},
live: {
libx264: {
default: defaultX264LiveOptionsBuilder
},
aac: {
default: defaultAACOptionsBuilder
}
}
}
private availableProfiles = {
vod: [] as string[],
live: [] as string[]
}
private constructor () {
this.buildAvailableProfiles()
}
getAvailableEncoders (): AvailableEncoders {
return {
available: this.availableEncoders,
encodersToTry: {
vod: {
video: this.getEncodersByPriority('vod', 'video'),
audio: this.getEncodersByPriority('vod', 'audio')
},
live: {
video: this.getEncodersByPriority('live', 'video'),
audio: this.getEncodersByPriority('live', 'audio')
}
}
}
}
getAvailableProfiles (type: 'vod' | 'live') {
return this.availableProfiles[type]
}
addProfile (options: {
type: 'vod' | 'live'
encoder: string
profile: string
builder: EncoderOptionsBuilder
}) {
const { type, encoder, profile, builder } = options
const encoders = this.availableEncoders[type]
if (!encoders[encoder]) encoders[encoder] = {}
encoders[encoder][profile] = builder
this.buildAvailableProfiles()
}
removeProfile (options: {
type: 'vod' | 'live'
encoder: string
profile: string
}) {
const { type, encoder, profile } = options
delete this.availableEncoders[type][encoder][profile]
this.buildAvailableProfiles()
}
addEncoderPriority (type: 'vod' | 'live', streamType: 'audio' | 'video', encoder: string, priority: number) {
this.encodersPriorities[type][streamType].push({ name: encoder, priority })
resetSupportedEncoders()
}
removeEncoderPriority (type: 'vod' | 'live', streamType: 'audio' | 'video', encoder: string, priority: number) {
this.encodersPriorities[type][streamType] = this.encodersPriorities[type][streamType]
.filter(o => o.name !== encoder && o.priority !== priority)
resetSupportedEncoders()
}
private getEncodersByPriority (type: 'vod' | 'live', streamType: 'audio' | 'video') {
return this.encodersPriorities[type][streamType]
.sort((e1, e2) => {
if (e1.priority > e2.priority) return -1
else if (e1.priority === e2.priority) return 0
return 1
})
.map(e => e.name)
}
private buildAvailableProfiles () {
for (const type of [ 'vod', 'live' ]) {
const result = new Set()
const encoders = this.availableEncoders[type]
for (const encoderName of Object.keys(encoders)) {
for (const profile of Object.keys(encoders[encoderName])) {
result.add(profile)
}
}
this.availableProfiles[type] = Array.from(result)
}
logger.debug('Available transcoding profiles built.', { availableProfiles: this.availableProfiles })
}
private buildDefaultEncodersPriorities () {
return {
video: [
{ name: 'libx264', priority: 100 }
],
// Try the first one, if not available try the second one etc
audio: [
// we favor VBR, if a good AAC encoder is available
{ name: 'libfdk_aac', priority: 200 },
{ name: 'aac', priority: 100 }
]
}
}
static get Instance () {
return this.instance || (this.instance = new this())
}
}
// ---------------------------------------------------------------------------
export {
VideoTranscodingProfilesManager
}
// ---------------------------------------------------------------------------
function buildTargetBitrate (options: {
inputBitrate: number
resolution: VideoResolution
fps: number
}) {
const { inputBitrate, resolution, fps } = options
const targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS)
if (!inputBitrate) return targetBitrate
return Math.min(targetBitrate, inputBitrate)
}