1 files changed, 256 insertions, 0 deletions

diff --git a/server/lib/transcoding/video-transcoding-profiles.ts b/server/lib/transcoding/video-transcoding-profiles.ts
new file mode 100644
index 000000000..c5ea72a5f
--- /dev/null
+++ b/server/lib/transcoding/video-transcoding-profiles.ts
@@ -0,0 +1,256 @@
+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,
+  getVideoFileBitrate,
+  getVideoStreamFromFile
+} 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 ({ input, resolution, fps }) => {
+  const targetBitrate = await buildTargetBitrate({ input, resolution, fps })
+  if (!targetBitrate) return { outputOptions: [ ] }
+
+  return {
+    outputOptions: [
+      `-preset veryfast`,
+      `-r ${fps}`,
+      `-maxrate ${targetBitrate}`,
+      `-bufsize ${targetBitrate * 2}`
+    ]
+  }
+}
+
+const defaultX264LiveOptionsBuilder: EncoderOptionsBuilder = async ({ resolution, fps, streamNum }) => {
+  const targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS)
+
+  return {
+    outputOptions: [
+      `-preset veryfast`,
+      `${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
+}
+
+// ---------------------------------------------------------------------------
+async function buildTargetBitrate (options: {
+  input: string
+  resolution: VideoResolution
+  fps: number
+}) {
+  const { input, resolution, fps } = options
+  const probe = await ffprobePromise(input)
+
+  const videoStream = await getVideoStreamFromFile(input, probe)
+  if (!videoStream) return undefined
+
+  const targetBitrate = getTargetBitrate(resolution, fps, VIDEO_TRANSCODING_FPS)
+
+  // Don't transcode to an higher bitrate than the original file
+  const fileBitrate = await getVideoFileBitrate(input, probe)
+  return Math.min(targetBitrate, fileBitrate)
+}