Loudness normalization

config/default.yaml

@@ -635,6 +635,10 @@ transcoding:
   web_videos:
     enabled: false
 
+  # Apply dynamic loudness normalization when transcoding audio
+  audio_loudnorm:
+    enabled: false
+
   # /!\ Requires ffmpeg >= 4.1
   # Generate HLS playlists and fragmented MP4 files. Better playback than with Web Videos:
   #     * Resolution change is smoother
@@ -726,6 +730,10 @@ live:
     # Available in core PeerTube: 'default'
     profile: 'default'
 
+    # Apply dynamic loudness normalization when transcoding audio in live
+    audio_loudnorm:
+      enabled: false
+
     resolutions:
       0p: false # Audio only
       144p: false

packages/ffmpeg/src/ffmpeg-command-wrapper.ts

@@ -21,6 +21,8 @@ export interface FFmpegCommandWrapperOptions {
   logger: SimpleLogger
   lTags?: { tags: string[] }
 
+  audioLoudnorm?: boolean
+
   updateJobProgress?: (progress?: number) => void
   onEnd?: () => void
   onError?: (err: Error) => void
@@ -39,6 +41,8 @@ export class FFmpegCommandWrapper {
   private readonly logger: SimpleLogger
   private readonly lTags: { tags: string[] }
 
+  private readonly audioLoudnorm: boolean
+
   private readonly updateJobProgress: (progress?: number) => void
   private readonly onEnd?: () => void
   private readonly onError?: (err: Error) => void
@@ -54,6 +58,8 @@ export class FFmpegCommandWrapper {
     this.logger = options.logger
     this.lTags = options.lTags || { tags: [] }
 
+    this.audioLoudnorm = options.audioLoudnorm === true
+
     this.updateJobProgress = options.updateJobProgress
 
     this.onEnd = options.onEnd
@@ -72,6 +78,10 @@ export class FFmpegCommandWrapper {
     return this.command
   }
 
+  isAudioLoudnormEnabled () {
+    return this.audioLoudnorm === true
+  }
+
   // ---------------------------------------------------------------------------
 
   debugLog (msg: string, meta: any = {}) {
@@ -182,6 +192,11 @@ export class FFmpegCommandWrapper {
 
     const { streamType, videoType } = options
 
+    // Force re-encode audio if loudnorm is enabled
+    if (streamType === 'audio' && this.audioLoudnorm) {
+      options.canCopyAudio = false
+    }
+
     const encodersToTry = this.availableEncoders.encodersToTry[videoType][streamType]
     const encoders = this.availableEncoders.available[videoType]
 
@@ -210,6 +225,9 @@ export class FFmpegCommandWrapper {
         }
       }
 
+      // propagate audioLoudnorm flag to the profile builder
+      ;(options as any).audioLoudnorm = this.audioLoudnorm
+
       const result = await builder(
         pick(options, [
           'input',
@@ -220,7 +238,8 @@ export class FFmpegCommandWrapper {
           'inputProbe',
           'fps',
           'inputRatio',
-          'streamNum'
+          'streamNum',
+          'audioLoudnorm'
         ])
       )
 

packages/ffmpeg/src/ffmpeg-default-transcoding-profile.ts

@@ -11,6 +11,8 @@ import {
 import { EncoderOptionsBuilder, EncoderOptionsBuilderParams } from '@peertube/peertube-models'
 import { FfprobeData } from 'fluent-ffmpeg'
 
+const LOUDNORM_FILTER = 'loudnorm=I=-14:TP=-1:LRA=11:linear=false'
+
 const defaultX264VODOptionsBuilder: EncoderOptionsBuilder = (options: EncoderOptionsBuilderParams) => {
   const { fps, inputRatio, inputBitrate, resolution } = options
 
@@ -40,7 +42,7 @@ const defaultX264LiveOptionsBuilder: EncoderOptionsBuilder = (options: EncoderOp
   }
 }
 
-const defaultAACOptionsBuilder: EncoderOptionsBuilder = async ({ input, streamNum, canCopyAudio, inputProbe }) => {
+const defaultAACOptionsBuilder: EncoderOptionsBuilder = async ({ input, streamNum, canCopyAudio, inputProbe, audioLoudnorm }) => {
   if (canCopyAudio && await canDoQuickAudioTranscode(input, inputProbe)) {
     return { copy: true, outputOptions: [] }
   }
@@ -57,15 +59,29 @@ const defaultAACOptionsBuilder: EncoderOptionsBuilder = async ({ input, streamNu
   // Force stereo as it causes some issues with HLS playback in Chrome
   const base = [ '-channel_layout', 'stereo' ]
 
+  const opts = base.slice()
+
+  if (audioLoudnorm) {
+    opts.push(buildStreamSuffix('-filter:a', streamNum), LOUDNORM_FILTER)
+  }
+
   if (bitrate !== -1) {
-    return { outputOptions: base.concat([ buildStreamSuffix('-b:a', streamNum), bitrate + 'k' ]) }
+    return { outputOptions: opts.concat([ buildStreamSuffix('-b:a', streamNum), bitrate + 'k' ]) }
   }
 
-  return { outputOptions: base }
+  return { outputOptions: opts }
 }
 
-const defaultLibFDKAACVODOptionsBuilder: EncoderOptionsBuilder = ({ streamNum }) => {
-  return { outputOptions: [ buildStreamSuffix('-q:a', streamNum), '5' ] }
+const defaultLibFDKAACVODOptionsBuilder: EncoderOptionsBuilder = ({ streamNum, audioLoudnorm }) => {
+  const outputOptions: string[] = []
+
+  if (audioLoudnorm) {
+    outputOptions.push(buildStreamSuffix('-filter:a', streamNum), LOUDNORM_FILTER)
+  }
+
+  outputOptions.push(buildStreamSuffix('-q:a', streamNum), '5')
+
+  return { outputOptions }
 }
 
 export function getDefaultAvailableEncoders () {

packages/ffmpeg/src/ffmpeg-vod.ts

@@ -203,7 +203,7 @@ export class FFmpegVOD {
 
     const videoPath = this.getHLSVideoPath(options)
 
-    if (options.copyCodecs) {
+    if (options.copyCodecs && !this.commandWrapper.isAudioLoudnormEnabled()) {
       presetCopy(this.commandWrapper, {
         withAudio: !options.separatedAudio || !options.resolution,
         withVideo: !options.separatedAudio || !!options.resolution

packages/models/src/server/custom-config.model.ts

@@ -199,6 +199,10 @@ export interface CustomConfig {
       enabled: boolean
       splitAudioAndVideo: boolean
     }
+
+    audioLoudnorm?: {
+      enabled: boolean
+    }
   }
 
   live: {
@@ -228,6 +232,10 @@ export interface CustomConfig {
       fps: {
         max: number
       }
+
+      audioLoudnorm?: {
+        enabled: boolean
+      }
     }
   }
 

packages/models/src/videos/transcoding/video-transcoding.model.ts

@@ -20,6 +20,9 @@ export type EncoderOptionsBuilderParams = {
 
   // For lives
   streamNum?: number
+
+  // Flag to enforce audio loudness normalization
+  audioLoudnorm?: boolean
 }
 
 export type EncoderOptionsBuilder = (params: EncoderOptionsBuilderParams) => Promise<EncoderOptions> | EncoderOptions

server/core/controllers/api/config.ts

@@ -422,6 +422,9 @@ function customConfig (): CustomConfig {
       originalFile: {
         keep: CONFIG.TRANSCODING.ORIGINAL_FILE.KEEP
       },
+      audioLoudnorm: {
+        enabled: CONFIG.TRANSCODING.AUDIO_LOUDNORM.ENABLED
+      },
       remoteRunners: {
         enabled: CONFIG.TRANSCODING.REMOTE_RUNNERS.ENABLED
       },
@@ -467,6 +470,9 @@ function customConfig (): CustomConfig {
         remoteRunners: {
           enabled: CONFIG.LIVE.TRANSCODING.REMOTE_RUNNERS.ENABLED
         },
+        audioLoudnorm: {
+          enabled: CONFIG.LIVE.TRANSCODING.AUDIO_LOUDNORM.ENABLED
+        },
         threads: CONFIG.LIVE.TRANSCODING.THREADS,
         profile: CONFIG.LIVE.TRANSCODING.PROFILE,
         resolutions: {

server/core/helpers/ffmpeg/ffmpeg-options.ts

@@ -21,7 +21,12 @@ export function getFFmpegCommandWrapperOptions (type: CommandType, availableEnco
       warn: logger.warn.bind(logger),
       error: logger.error.bind(logger)
     },
-    lTags: { tags: [ 'ffmpeg' ] }
+    lTags: { tags: [ 'ffmpeg' ] },
+    audioLoudnorm: type === 'vod'
+      ? CONFIG.TRANSCODING.AUDIO_LOUDNORM.ENABLED
+      : type === 'live'
+        ? CONFIG.LIVE.TRANSCODING.AUDIO_LOUDNORM.ENABLED
+        : false
   }
 }
 

server/core/initializers/config.ts

@@ -578,6 +578,12 @@ const CONFIG = {
     get PROFILE () {
       return config.get<string>('transcoding.profile')
     },
+
+    AUDIO_LOUDNORM: {
+      get ENABLED () {
+        return config.get<boolean>('transcoding.audio_loudnorm.enabled')
+      }
+    },
     get ALWAYS_TRANSCODE_ORIGINAL_RESOLUTION () {
       return config.get<boolean>('transcoding.always_transcode_original_resolution')
     },
@@ -706,6 +712,12 @@ const CONFIG = {
         return config.get<string>('live.transcoding.profile')
       },
 
+      AUDIO_LOUDNORM: {
+        get ENABLED () {
+          return config.get<boolean>('live.transcoding.audio_loudnorm.enabled')
+        }
+      },
+
       get ALWAYS_TRANSCODE_ORIGINAL_RESOLUTION () {
         return config.get<boolean>('live.transcoding.always_transcode_original_resolution')
       },