audiobookshelf/server/objects/Stream.js

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const Ffmpeg = require('fluent-ffmpeg')
const EventEmitter = require('events')
const Path = require('path')
const fs = require('fs-extra')
const Logger = require('../Logger')
const { secondsToTimestamp } = require('../utils/fileUtils')
const { writeConcatFile } = require('../utils/ffmpegHelpers')
const hlsPlaylistGenerator = require('../utils/hlsPlaylistGenerator')
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class Stream extends EventEmitter {
constructor(streamPath, client, audiobook) {
super()
this.id = (Date.now() + Math.trunc(Math.random() * 1000)).toString(36)
this.client = client
this.audiobook = audiobook
this.segmentLength = 6
this.segmentBasename = 'output-%d.ts'
this.streamPath = Path.join(streamPath, this.id)
this.concatFilesPath = Path.join(this.streamPath, 'files.txt')
this.playlistPath = Path.join(this.streamPath, 'output.m3u8')
this.finalPlaylistPath = Path.join(this.streamPath, 'final-output.m3u8')
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this.startTime = 0
this.ffmpeg = null
this.loop = null
this.isResetting = false
this.isClientInitialized = false
this.isTranscodeComplete = false
this.segmentsCreated = new Set()
this.furthestSegmentCreated = 0
this.clientCurrentTime = 0
this.init()
}
get socket() {
return this.client.socket
}
get audiobookId() {
return this.audiobook.id
}
get audiobookTitle() {
return this.audiobook ? this.audiobook.title : null
}
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get totalDuration() {
return this.audiobook.totalDuration
}
get segmentStartNumber() {
if (!this.startTime) return 0
return Math.floor(this.startTime / this.segmentLength)
}
get numSegments() {
var numSegs = Math.floor(this.totalDuration / this.segmentLength)
if (this.totalDuration - (numSegs * this.segmentLength) > 0) {
numSegs++
}
return numSegs
}
get tracks() {
return this.audiobook.tracks
}
get clientPlaylistUri() {
return `/hls/${this.id}/output.m3u8`
}
get clientProgress() {
if (!this.clientCurrentTime) return 0
return Number((this.clientCurrentTime / this.totalDuration).toFixed(3))
}
toJSON() {
return {
id: this.id,
clientId: this.client.id,
userId: this.client.user.id,
audiobook: this.audiobook.toJSONMinified(),
segmentLength: this.segmentLength,
playlistPath: this.playlistPath,
clientPlaylistUri: this.clientPlaylistUri,
clientCurrentTime: this.clientCurrentTime,
startTime: this.startTime,
segmentStartNumber: this.segmentStartNumber,
isTranscodeComplete: this.isTranscodeComplete
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}
}
init() {
var clientUserAudiobooks = this.client.user ? this.client.user.audiobooks || {} : {}
var userAudiobook = clientUserAudiobooks[this.audiobookId] || null
if (userAudiobook) {
var timeRemaining = this.totalDuration - userAudiobook.currentTime
Logger.info('[STREAM] User has progress for audiobook', userAudiobook, `Time Remaining: ${timeRemaining}s`)
if (timeRemaining > 15) {
this.startTime = userAudiobook.currentTime
this.clientCurrentTime = this.startTime
}
}
}
async checkSegmentNumberRequest(segNum) {
var segStartTime = segNum * this.segmentLength
if (this.startTime > segStartTime) {
Logger.warn(`[STREAM] Segment #${segNum} Request @${secondsToTimestamp(segStartTime)} is before start time (${secondsToTimestamp(this.startTime)}) - Reset Transcode`)
await this.reset(segStartTime - (this.segmentLength * 2))
return segStartTime
} else if (this.isTranscodeComplete) {
return false
}
var distanceFromFurthestSegment = segNum - this.furthestSegmentCreated
if (distanceFromFurthestSegment > 10) {
Logger.info(`Segment #${segNum} requested is ${distanceFromFurthestSegment} segments from latest (${secondsToTimestamp(segStartTime)}) - Reset Transcode`)
await this.reset(segStartTime - (this.segmentLength * 2))
return segStartTime
}
return false
}
updateClientCurrentTime(currentTime) {
Logger.debug('[Stream] Updated client current time', secondsToTimestamp(currentTime))
this.clientCurrentTime = currentTime
}
async generatePlaylist() {
fs.ensureDirSync(this.streamPath)
await hlsPlaylistGenerator(this.playlistPath, 'output', this.totalDuration, this.segmentLength)
return this.clientPlaylistUri
}
async checkFiles() {
try {
var files = await fs.readdir(this.streamPath)
files.forEach((file) => {
var extname = Path.extname(file)
if (extname === '.ts') {
var basename = Path.basename(file, extname)
var num_part = basename.split('-')[1]
var part_num = Number(num_part)
this.segmentsCreated.add(part_num)
}
})
if (!this.segmentsCreated.size) {
Logger.warn('No Segments')
return
}
if (this.segmentsCreated.size > 6 && !this.isClientInitialized) {
this.isClientInitialized = true
Logger.info(`[STREAM] ${this.id} notifying client that stream is ready`)
this.socket.emit('stream_open', this.toJSON())
}
var chunks = []
var current_chunk = []
var last_seg_in_chunk = -1
var segments = Array.from(this.segmentsCreated).sort((a, b) => a - b);
var lastSegment = segments[segments.length - 1]
if (lastSegment > this.furthestSegmentCreated) {
this.furthestSegmentCreated = lastSegment
}
// console.log('SORT', [...this.segmentsCreated].slice(0, 200).join(', '), segments.slice(0, 200).join(', '))
segments.forEach((seg) => {
if (!current_chunk.length || last_seg_in_chunk + 1 === seg) {
last_seg_in_chunk = seg
current_chunk.push(seg)
} else {
// console.log('Last Seg is not equal to - 1', last_seg_in_chunk, seg)
if (current_chunk.length === 1) chunks.push(current_chunk[0])
else chunks.push(`${current_chunk[0]}-${current_chunk[current_chunk.length - 1]}`)
last_seg_in_chunk = seg
current_chunk = [seg]
}
})
if (current_chunk.length) {
if (current_chunk.length === 1) chunks.push(current_chunk[0])
else chunks.push(`${current_chunk[0]}-${current_chunk[current_chunk.length - 1]}`)
}
var perc = (this.segmentsCreated.size * 100 / this.numSegments).toFixed(2) + '%'
Logger.info('[STREAM-CHECK] Check Files', this.segmentsCreated.size, 'of', this.numSegments, perc, `Furthest Segment: ${this.furthestSegmentCreated}`)
Logger.info('[STREAM-CHECK] Chunks', chunks.join(', '))
this.socket.emit('stream_progress', {
stream: this.id,
percent: perc,
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chunks,
numSegments: this.numSegments
})
} catch (error) {
Logger.error('Failed checkign files', error)
}
}
startLoop() {
// Logger.info(`[Stream] ${this.audiobookTitle} (${this.id}) Start Loop`)
this.socket.emit('stream_progress', { stream: this.id, chunks: [], numSegments: 0, percent: '0%' })
clearInterval(this.loop)
var intervalId = setInterval(() => {
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if (!this.isTranscodeComplete) {
this.checkFiles()
} else {
Logger.info(`[Stream] ${this.audiobookTitle} sending stream_ready`)
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this.socket.emit('stream_ready')
clearInterval(intervalId)
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}
}, 2000)
this.loop = intervalId
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}
async start() {
Logger.info(`[STREAM] START STREAM - Num Segments: ${this.numSegments}`)
this.ffmpeg = Ffmpeg()
var trackStartTime = await writeConcatFile(this.tracks, this.concatFilesPath, this.startTime)
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this.ffmpeg.addInput(this.concatFilesPath)
this.ffmpeg.inputFormat('concat')
this.ffmpeg.inputOption('-safe 0')
if (this.startTime > 0) {
const shiftedStartTime = this.startTime - trackStartTime
Logger.info(`[STREAM] Starting Stream at startTime ${secondsToTimestamp(this.startTime)} and Segment #${this.segmentStartNumber}`)
this.ffmpeg.inputOption(`-ss ${shiftedStartTime}`)
this.ffmpeg.inputOption('-noaccurate_seek')
}
const logLevel = process.env.NODE_ENV === 'production' ? 'error' : 'warning'
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this.ffmpeg.addOption([
`-loglevel ${logLevel}`,
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'-map 0:a',
'-c:a copy'
])
this.ffmpeg.addOption([
'-f hls',
"-copyts",
"-avoid_negative_ts disabled",
"-max_delay 5000000",
"-max_muxing_queue_size 2048",
`-hls_time 6`,
"-hls_segment_type mpegts",
`-start_number ${this.segmentStartNumber}`,
"-hls_playlist_type vod",
"-hls_list_size 0",
"-hls_allow_cache 0"
])
var segmentFilename = Path.join(this.streamPath, this.segmentBasename)
this.ffmpeg.addOption(`-hls_segment_filename ${segmentFilename}`)
this.ffmpeg.output(this.finalPlaylistPath)
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this.ffmpeg.on('start', (command) => {
Logger.info('[INFO] FFMPEG transcoding started with command: ' + command)
Logger.info('')
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if (this.isResetting) {
setTimeout(() => {
Logger.info('[STREAM] Clearing isResetting')
this.isResetting = false
this.startLoop()
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}, 500)
} else {
this.startLoop()
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}
})
this.ffmpeg.on('stderr', (stdErrline) => {
Logger.info(stdErrline)
})
this.ffmpeg.on('error', (err, stdout, stderr) => {
if (err.message && err.message.includes('SIGKILL')) {
// This is an intentional SIGKILL
Logger.info('[FFMPEG] Transcode Killed')
this.ffmpeg = null
} else {
Logger.error('Ffmpeg Err', err.message)
}
clearInterval(this.loop)
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})
this.ffmpeg.on('end', (stdout, stderr) => {
Logger.info('[FFMPEG] Transcoding ended')
// For very small fast load
if (!this.isClientInitialized) {
this.isClientInitialized = true
Logger.info(`[STREAM] ${this.id} notifying client that stream is ready`)
this.socket.emit('stream_open', this.toJSON())
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}
this.isTranscodeComplete = true
this.ffmpeg = null
clearInterval(this.loop)
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})
this.ffmpeg.run()
}
async close() {
clearInterval(this.loop)
Logger.info('Closing Stream', this.id)
if (this.ffmpeg) {
this.ffmpeg.kill('SIGKILL')
}
await fs.remove(this.streamPath).then(() => {
Logger.info('Deleted session data', this.streamPath)
}).catch((err) => {
Logger.error('Failed to delete session data', err)
})
this.client.socket.emit('stream_closed', this.id)
this.emit('closed')
}
cancelTranscode() {
clearInterval(this.loop)
if (this.ffmpeg) {
this.ffmpeg.kill('SIGKILL')
}
}
async waitCancelTranscode() {
for (let i = 0; i < 20; i++) {
if (!this.ffmpeg) return true
await new Promise((resolve) => setTimeout(resolve, 500))
}
Logger.error('[STREAM] Transcode never closed...')
return false
}
async reset(time) {
if (this.isResetting) {
return Logger.info(`[STREAM] Stream ${this.id} already resetting`)
}
time = Math.max(0, time)
this.isResetting = true
if (this.ffmpeg) {
this.cancelTranscode()
await this.waitCancelTranscode()
}
this.isTranscodeComplete = false
this.startTime = time
this.clientCurrentTime = this.startTime
Logger.info(`Stream Reset New Start Time ${secondsToTimestamp(this.startTime)}`)
this.start()
}
}
module.exports = Stream