audiobookshelf/server/objects/Stream.js

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JavaScript
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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 { getId, secondsToTimestamp } = require('../utils/index')
const { writeConcatFile } = require('../utils/ffmpegHelpers')
const hlsPlaylistGenerator = require('../utils/hlsPlaylistGenerator')
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const UserListeningSession = require('./UserListeningSession')
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class Stream extends EventEmitter {
constructor(streamPath, client, audiobook, transcodeOptions = {}) {
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super()
this.id = getId('str')
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this.client = client
this.audiobook = audiobook
this.transcodeOptions = transcodeOptions
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this.segmentLength = 6
this.maxSeekBackTime = 30
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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.listeningSession = new UserListeningSession()
this.listeningSession.setData(audiobook, client.user)
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this.init()
}
get socket() {
return this.client ? this.client.socket || null : null
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}
get audiobookId() {
return this.audiobook.id
}
get audiobookTitle() {
return this.audiobook ? this.audiobook.title : null
}
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get totalDuration() {
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return this.audiobook.duration
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}
get tracksAudioFileType() {
if (!this.tracks.length) return null
return this.tracks[0].ext.toLowerCase().slice(1)
}
get hlsSegmentType() {
var hasFlac = this.tracks.find(t => t.ext.toLowerCase() === '.flac')
return hasFlac ? 'fmp4' : 'mpegts'
}
get segmentBasename() {
if (this.hlsSegmentType === 'fmp4') return 'output-%d.m4s'
return 'output-%d.ts'
}
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get segmentStartNumber() {
if (!this.startTime) return 0
return Math.floor(Math.max(this.startTime - this.maxSeekBackTime, 0) / this.segmentLength)
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}
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 clientUser() {
return this.client ? this.client.user || {} : null
}
get userToken() {
return this.clientUser ? this.clientUser.token : null
}
get clientUserAudiobooks() {
return this.client ? this.clientUser.audiobooks || {} : null
}
get clientUserAudiobookData() {
return this.client ? this.clientUserAudiobooks[this.audiobookId] : null
}
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get clientPlaylistUri() {
return `/hls/${this.id}/output.m3u8`
}
get clientProgress() {
if (!this.clientCurrentTime) return 0
var prog = Math.min(1, this.clientCurrentTime / this.totalDuration)
return Number(prog.toFixed(3))
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}
get isAACEncodable() {
return ['mp4', 'm4a', 'm4b'].includes(this.tracksAudioFileType)
}
get transcodeForceAAC() {
return !!this.transcodeOptions.forceAAC
}
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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,
lastUpdate: this.clientUserAudiobookData ? this.clientUserAudiobookData.lastUpdate : 0
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}
}
init() {
if (this.clientUserAudiobookData) {
var timeRemaining = this.totalDuration - this.clientUserAudiobookData.currentTime
Logger.info('[STREAM] User has progress for audiobook', this.clientUserAudiobookData.progress, `Time Remaining: ${timeRemaining}s`)
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if (timeRemaining > 15) {
this.startTime = this.clientUserAudiobookData.currentTime
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this.clientCurrentTime = this.startTime
}
}
}
async checkSegmentNumberRequest(segNum) {
var segStartTime = segNum * this.segmentLength
if (this.startTime > segStartTime) {
Logger.warn(`[STREAM] Segment #${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
}
syncStream({ timeListened, currentTime }) {
var syncLog = ''
if (currentTime !== null && !isNaN(currentTime)) {
syncLog = `Update client current time ${secondsToTimestamp(currentTime)}`
this.clientCurrentTime = currentTime
}
var saveListeningSession = false
if (timeListened && !isNaN(timeListened)) {
// Check if listening session should roll to next day
if (this.listeningSession.checkDateRollover()) {
if (!this.clientUser) {
Logger.error(`[Stream] Sync stream invalid client user`)
return null
}
this.listeningSession = new UserListeningSession()
this.listeningSession.setData(this.audiobook, this.clientUser)
Logger.debug(`[Stream] Listening session rolled to next day`)
}
this.listeningSession.addListeningTime(timeListened)
if (syncLog) syncLog += ' | '
syncLog += `Add listening time ${timeListened}s, Total time listened ${this.listeningSession.timeListening}s`
saveListeningSession = true
}
Logger.debug('[Stream]', syncLog)
return saveListeningSession ? this.listeningSession : null
}
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async generatePlaylist() {
fs.ensureDirSync(this.streamPath)
await hlsPlaylistGenerator(this.playlistPath, 'output', this.totalDuration, this.segmentLength, this.hlsSegmentType, this.userToken)
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return this.clientPlaylistUri
}
async checkFiles() {
try {
var files = await fs.readdir(this.streamPath)
files.forEach((file) => {
var extname = Path.extname(file)
if (extname === '.ts' || extname === '.m4s') {
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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
if (this.socket) {
Logger.info(`[STREAM] ${this.id} notifying client that stream is ready`)
this.socket.emit('stream_open', this.toJSON())
}
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}
var chunks = []
var current_chunk = []
var last_seg_in_chunk = -1
var segments = Array.from(this.segmentsCreated).sort((a, b) => a - b);
var lastSegment = segments[segments.length - 1]
if (lastSegment > this.furthestSegmentCreated) {
this.furthestSegmentCreated = lastSegment
}
segments.forEach((seg) => {
if (!current_chunk.length || last_seg_in_chunk + 1 === seg) {
last_seg_in_chunk = seg
current_chunk.push(seg)
} else {
if (current_chunk.length === 1) chunks.push(current_chunk[0])
else chunks.push(`${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.debug('[STREAM-CHECK] Chunks', chunks.join(', '))
if (this.socket) {
this.socket.emit('stream_progress', {
stream: this.id,
percent: perc,
chunks,
numSegments: this.numSegments
})
}
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} catch (error) {
Logger.error('Failed checking files', error)
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}
}
startLoop() {
// Logger.info(`[Stream] ${this.audiobookTitle} (${this.id}) Start Loop`)
if (this.socket) {
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 {
if (this.socket) {
Logger.info(`[Stream] ${this.audiobookTitle} sending stream_ready`)
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 adjustedStartTime = Math.max(this.startTime - this.maxSeekBackTime, 0)
var trackStartTime = await writeConcatFile(this.tracks, this.concatFilesPath, adjustedStartTime)
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this.ffmpeg.addInput(this.concatFilesPath)
// seek_timestamp : https://ffmpeg.org/ffmpeg.html
// the argument to the -ss option is considered an actual timestamp, and is not offset by the start time of the file
// fixes https://github.com/advplyr/audiobookshelf/issues/116
this.ffmpeg.inputOption('-seek_timestamp 1')
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this.ffmpeg.inputFormat('concat')
this.ffmpeg.inputOption('-safe 0')
if (adjustedStartTime > 0) {
const shiftedStartTime = adjustedStartTime - trackStartTime
// Issues using exact fractional seconds i.e. 29.49814 - changing to 29.5s
var startTimeS = Math.round(shiftedStartTime * 10) / 10 + 's'
Logger.info(`[STREAM] Starting Stream at startTime ${secondsToTimestamp(adjustedStartTime)} (User startTime ${secondsToTimestamp(this.startTime)}) and Segment #${this.segmentStartNumber}`)
this.ffmpeg.inputOption(`-ss ${startTimeS}`)
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this.ffmpeg.inputOption('-noaccurate_seek')
}
const logLevel = process.env.NODE_ENV === 'production' ? 'error' : 'warning'
const audioCodec = (this.hlsSegmentType === 'fmp4' || this.tracksAudioFileType === 'opus' || this.transcodeForceAAC) ? 'aac' : 'copy'
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this.ffmpeg.addOption([
`-loglevel ${logLevel}`,
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'-map 0:a',
`-c:a ${audioCodec}`
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])
const hlsOptions = [
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'-f hls',
"-copyts",
"-avoid_negative_ts make_non_negative",
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"-max_delay 5000000",
"-max_muxing_queue_size 2048",
`-hls_time 6`,
`-hls_segment_type ${this.hlsSegmentType}`,
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`-start_number ${this.segmentStartNumber}`,
"-hls_playlist_type vod",
"-hls_list_size 0",
"-hls_allow_cache 0"
]
if (this.hlsSegmentType === 'fmp4') {
hlsOptions.push('-strict -2')
// var fmp4InitFilename = Path.join(this.streamPath, 'init.mp4')
var fmp4InitFilename = 'init.mp4'
hlsOptions.push(`-hls_fmp4_init_filename ${fmp4InitFilename}`)
}
this.ffmpeg.addOption(hlsOptions)
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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) {
// AAC encode is much slower
const clearIsResettingTime = this.transcodeForceAAC ? 3000 : 500
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setTimeout(() => {
Logger.info('[STREAM] Clearing isResetting')
this.isResetting = false
this.startLoop()
}, clearIsResettingTime)
} 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
clearInterval(this.loop)
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} else {
Logger.error('Ffmpeg Err', '"' + err.message + '"')
// Temporary workaround for https://github.com/advplyr/audiobookshelf/issues/172
const aacErrorMsg = 'ffmpeg exited with code 1: Could not write header for output file #0 (incorrect codec parameters ?)'
if (audioCodec === 'copy' && this.isAACEncodable && err.message && err.message.startsWith(aacErrorMsg)) {
Logger.info(`[Stream] Re-attempting stream with AAC encode`)
this.transcodeOptions.forceAAC = true
this.reset(this.startTime)
} else {
// Close stream show error
this.close(err.message)
}
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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
if (this.socket) {
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(errorMessage = null) {
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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)
})
if (this.socket) {
if (errorMessage) this.socket.emit('stream_error', { id: this.id, error: (errorMessage || '').trim() })
else this.socket.emit('stream_closed', this.id)
}
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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