Add latency setting support

42 files changed, 516 insertions, 81 deletions

diff --git a/client/src/app/+admin/config/edit-custom-config/edit-custom-config.component.ts b/client/src/app/+admin/config/edit-custom-config/edit-custom-config.component.ts
index e3b6f8305..94f1021bf 100644
--- a/client/src/app/+admin/config/edit-custom-config/edit-custom-config.component.ts
+++ b/client/src/app/+admin/config/edit-custom-config/edit-custom-config.component.ts
@@ -189,6 +189,9 @@ export class EditCustomConfigComponent extends FormReactive implements OnInit {
         maxInstanceLives: MAX_INSTANCE_LIVES_VALIDATOR,
         maxUserLives: MAX_USER_LIVES_VALIDATOR,
         allowReplay: null,
+        latencySetting: {
+          enabled: null
+        },
 
         transcoding: {
           enabled: null,
diff --git a/client/src/app/+admin/config/edit-custom-config/edit-live-configuration.component.html b/client/src/app/+admin/config/edit-custom-config/edit-live-configuration.component.html
index 10d5278c1..8d6a4ce19 100644
--- a/client/src/app/+admin/config/edit-custom-config/edit-live-configuration.component.html
+++ b/client/src/app/+admin/config/edit-custom-config/edit-live-configuration.component.html
@@ -36,6 +36,18 @@
                 </my-peertube-checkbox>
               </div>
 
+              <div class="form-group" formGroupName="latencySetting" [ngClass]="getDisabledLiveClass()">
+                <my-peertube-checkbox
+                  inputName="liveLatencySettingEnabled" formControlName="enabled"
+                  i18n-labelText labelText="Allow your users to change live latency"
+                >
+                  <ng-container ngProjectAs="description" i18n>
+                    Small latency disables P2P and high latency can increase P2P ratio
+                  </ng-container>
+
+                </my-peertube-checkbox>
+              </div>
+
               <div class="form-group" [ngClass]="getDisabledLiveClass()">
                 <label i18n for="liveMaxInstanceLives">
                   Max simultaneous lives created on your instance <span class="text-muted">(-1 for "unlimited")</span>
diff --git a/client/src/app/+videos/+video-edit/shared/video-edit.component.html b/client/src/app/+videos/+video-edit/shared/video-edit.component.html
index 2281f8631..515daf15f 100644
--- a/client/src/app/+videos/+video-edit/shared/video-edit.component.html
+++ b/client/src/app/+videos/+video-edit/shared/video-edit.component.html
@@ -289,6 +289,17 @@
                 </ng-container>
               </my-peertube-checkbox>
             </div>
+
+            <div class="form-group" *ngIf="isLatencyModeEnabled()">
+              <label i18n for="latencyMode">Latency mode</label>
+              <my-select-options
+                labelForId="latencyMode" [items]="latencyModes" formControlName="latencyMode" [clearable]="true"
+              ></my-select-options>
+
+              <div *ngIf="formErrors.latencyMode" class="form-error">
+                {{ formErrors.latencyMode }}
+              </div>
+            </div>
           </div>
         </div>
       </ng-template>
diff --git a/client/src/app/+videos/+video-edit/shared/video-edit.component.ts b/client/src/app/+videos/+video-edit/shared/video-edit.component.ts
index 2801fc519..a2399eafb 100644
--- a/client/src/app/+videos/+video-edit/shared/video-edit.component.ts
+++ b/client/src/app/+videos/+video-edit/shared/video-edit.component.ts
@@ -1,6 +1,6 @@
 import { forkJoin } from 'rxjs'
 import { map } from 'rxjs/operators'
-import { SelectChannelItem } from 'src/types/select-options-item.model'
+import { SelectChannelItem, SelectOptionsItem } from 'src/types/select-options-item.model'
 import { ChangeDetectorRef, Component, EventEmitter, Input, NgZone, OnDestroy, OnInit, Output, ViewChild } from '@angular/core'
 import { AbstractControl, FormArray, FormControl, FormGroup, Validators } from '@angular/forms'
 import { HooksService, PluginService, ServerService } from '@app/core'
@@ -26,6 +26,7 @@ import { PluginInfo } from '@root-helpers/plugins-manager'
 import {
   HTMLServerConfig,
   LiveVideo,
+  LiveVideoLatencyMode,
   RegisterClientFormFieldOptions,
   RegisterClientVideoFieldOptions,
   VideoConstant,
@@ -78,6 +79,23 @@ export class VideoEditComponent implements OnInit, OnDestroy {
   videoCategories: VideoConstant<number>[] = []
   videoLicences: VideoConstant<number>[] = []
   videoLanguages: VideoLanguages[] = []
+  latencyModes: SelectOptionsItem[] = [
+    {
+      id: LiveVideoLatencyMode.SMALL_LATENCY,
+      label: $localize`Small latency`,
+      description: $localize`Reduce latency to ~15s disabling P2P`
+    },
+    {
+      id: LiveVideoLatencyMode.DEFAULT,
+      label: $localize`Default`,
+      description: $localize`Average latency of 30s`
+    },
+    {
+      id: LiveVideoLatencyMode.HIGH_LATENCY,
+      label: $localize`High latency`,
+      description: $localize`Average latency of 60s increasing P2P ratio`
+    }
+  ]
 
   pluginDataFormGroup: FormGroup
 
@@ -141,6 +159,7 @@ export class VideoEditComponent implements OnInit, OnDestroy {
       originallyPublishedAt: VIDEO_ORIGINALLY_PUBLISHED_AT_VALIDATOR,
       liveStreamKey: null,
       permanentLive: null,
+      latencyMode: null,
       saveReplay: null
     }
 
@@ -273,6 +292,10 @@ export class VideoEditComponent implements OnInit, OnDestroy {
     return this.form.value['permanentLive'] === true
   }
 
+  isLatencyModeEnabled () {
+    return this.serverConfig.live.latencySetting.enabled
+  }
+
   isPluginFieldHidden (pluginField: PluginField) {
     if (typeof pluginField.commonOptions.hidden !== 'function') return false
 
diff --git a/client/src/app/+videos/+video-edit/video-update.component.ts b/client/src/app/+videos/+video-edit/video-update.component.ts
index d9e8344fc..9c4998f2e 100644
--- a/client/src/app/+videos/+video-edit/video-update.component.ts
+++ b/client/src/app/+videos/+video-edit/video-update.component.ts
@@ -64,6 +64,7 @@ export class VideoUpdateComponent extends FormReactive implements OnInit {
     if (this.liveVideo) {
       this.form.patchValue({
         saveReplay: this.liveVideo.saveReplay,
+        latencyMode: this.liveVideo.latencyMode,
         permanentLive: this.liveVideo.permanentLive
       })
     }
@@ -127,7 +128,8 @@ export class VideoUpdateComponent extends FormReactive implements OnInit {
 
             const liveVideoUpdate: LiveVideoUpdate = {
               saveReplay: !!this.form.value.saveReplay,
-              permanentLive: !!this.form.value.permanentLive
+              permanentLive: !!this.form.value.permanentLive,
+              latencyMode: this.form.value.latencyMode
             }
 
             // Don't update live attributes if they did not change
diff --git a/client/src/app/+videos/+video-watch/video-watch.component.ts b/client/src/app/+videos/+video-watch/video-watch.component.ts
index 1f45c4d26..067d3bc84 100644
--- a/client/src/app/+videos/+video-watch/video-watch.component.ts
+++ b/client/src/app/+videos/+video-watch/video-watch.component.ts
@@ -1,5 +1,5 @@
 import { Hotkey, HotkeysService } from 'angular2-hotkeys'
-import { forkJoin, Subscription } from 'rxjs'
+import { forkJoin, map, Observable, of, Subscription, switchMap } from 'rxjs'
 import { isP2PEnabled } from 'src/assets/player/utils'
 import { PlatformLocation } from '@angular/common'
 import { Component, ElementRef, Inject, LOCALE_ID, NgZone, OnDestroy, OnInit, ViewChild } from '@angular/core'
@@ -22,11 +22,13 @@ import { HooksService } from '@app/core/plugins/hooks.service'
 import { isXPercentInViewport, scrollToTop } from '@app/helpers'
 import { Video, VideoCaptionService, VideoDetails, VideoService } from '@app/shared/shared-main'
 import { SubscribeButtonComponent } from '@app/shared/shared-user-subscription'
+import { LiveVideoService } from '@app/shared/shared-video-live'
 import { VideoPlaylist, VideoPlaylistService } from '@app/shared/shared-video-playlist'
 import { timeToInt } from '@shared/core-utils'
 import {
   HTMLServerConfig,
   HttpStatusCode,
+  LiveVideo,
   PeerTubeProblemDocument,
   ServerErrorCode,
   VideoCaption,
@@ -63,6 +65,7 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
 
   video: VideoDetails = null
   videoCaptions: VideoCaption[] = []
+  liveVideo: LiveVideo
 
   playlistPosition: number
   playlist: VideoPlaylist = null
@@ -89,6 +92,7 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
     private router: Router,
     private videoService: VideoService,
     private playlistService: VideoPlaylistService,
+    private liveVideoService: LiveVideoService,
     private confirmService: ConfirmService,
     private metaService: MetaService,
     private authService: AuthService,
@@ -239,12 +243,21 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
       'filter:api.video-watch.video.get.result'
     )
 
+    const videoAndLiveObs: Observable<{ video: VideoDetails, live?: LiveVideo }> = videoObs.pipe(
+      switchMap(video => {
+        if (!video.isLive) return of({ video })
+
+        return this.liveVideoService.getVideoLive(video.uuid)
+          .pipe(map(live => ({ live, video })))
+      })
+    )
+
     forkJoin([
-      videoObs,
+      videoAndLiveObs,
       this.videoCaptionService.listCaptions(videoId),
       this.userService.getAnonymousOrLoggedUser()
     ]).subscribe({
-      next: ([ video, captionsResult, loggedInOrAnonymousUser ]) => {
+      next: ([ { video, live }, captionsResult, loggedInOrAnonymousUser ]) => {
         const queryParams = this.route.snapshot.queryParams
 
         const urlOptions = {
@@ -261,7 +274,7 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
           peertubeLink: false
         }
 
-        this.onVideoFetched({ video, videoCaptions: captionsResult.data, loggedInOrAnonymousUser, urlOptions })
+        this.onVideoFetched({ video, live, videoCaptions: captionsResult.data, loggedInOrAnonymousUser, urlOptions })
             .catch(err => this.handleGlobalError(err))
       },
 
@@ -330,16 +343,18 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
 
   private async onVideoFetched (options: {
     video: VideoDetails
+    live: LiveVideo
     videoCaptions: VideoCaption[]
     urlOptions: URLOptions
     loggedInOrAnonymousUser: User
   }) {
-    const { video, videoCaptions, urlOptions, loggedInOrAnonymousUser } = options
+    const { video, live, videoCaptions, urlOptions, loggedInOrAnonymousUser } = options
 
     this.subscribeToLiveEventsIfNeeded(this.video, video)
 
     this.video = video
     this.videoCaptions = videoCaptions
+    this.liveVideo = live
 
     // Re init attributes
     this.playerPlaceholderImgSrc = undefined
@@ -387,6 +402,7 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
     const params = {
       video: this.video,
       videoCaptions: this.videoCaptions,
+      liveVideo: this.liveVideo,
       urlOptions,
       loggedInOrAnonymousUser,
       user: this.user
@@ -532,12 +548,13 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
 
   private buildPlayerManagerOptions (params: {
     video: VideoDetails
+    liveVideo: LiveVideo
     videoCaptions: VideoCaption[]
     urlOptions: CustomizationOptions & { playerMode: PlayerMode }
     loggedInOrAnonymousUser: User
     user?: AuthUser
   }) {
-    const { video, videoCaptions, urlOptions, loggedInOrAnonymousUser, user } = params
+    const { video, liveVideo, videoCaptions, urlOptions, loggedInOrAnonymousUser, user } = params
 
     const getStartTime = () => {
       const byUrl = urlOptions.startTime !== undefined
@@ -562,6 +579,10 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
       src: environment.apiUrl + c.captionPath
     }))
 
+    const liveOptions = video.isLive
+      ? { latencyMode: liveVideo.latencyMode }
+      : undefined
+
     const options: PeertubePlayerManagerOptions = {
       common: {
         autoplay: this.isAutoplay(),
@@ -597,6 +618,7 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
         embedTitle: video.name,
 
         isLive: video.isLive,
+        liveOptions,
 
         language: this.localeId,
 
diff --git a/client/src/assets/player/peertube-player-options-builder.ts b/client/src/assets/player/peertube-player-options-builder.ts
index 7a82b128d..c9cbbbf4d 100644
--- a/client/src/assets/player/peertube-player-options-builder.ts
+++ b/client/src/assets/player/peertube-player-options-builder.ts
@@ -1,9 +1,10 @@
 import videojs from 'video.js'
+import { HybridLoaderSettings } from '@peertube/p2p-media-loader-core'
 import { HlsJsEngineSettings } from '@peertube/p2p-media-loader-hlsjs'
 import { PluginsManager } from '@root-helpers/plugins-manager'
 import { buildVideoLink, decorateVideoLink } from '@shared/core-utils'
 import { isDefaultLocale } from '@shared/core-utils/i18n'
-import { VideoFile } from '@shared/models'
+import { LiveVideoLatencyMode, VideoFile } from '@shared/models'
 import { copyToClipboard } from '../../root-helpers/utils'
 import { RedundancyUrlManager } from './p2p-media-loader/redundancy-url-manager'
 import { segmentUrlBuilderFactory } from './p2p-media-loader/segment-url-builder'
@@ -19,7 +20,6 @@ import {
   VideoJSPluginOptions
 } from './peertube-videojs-typings'
 import { buildVideoOrPlaylistEmbed, getRtcConfig, isIOS, isSafari } from './utils'
-import { HybridLoaderSettings } from '@peertube/p2p-media-loader-core'
 
 export type PlayerMode = 'webtorrent' | 'p2p-media-loader'
 
@@ -76,6 +76,9 @@ export interface CommonOptions extends CustomizationOptions {
   embedTitle: string
 
   isLive: boolean
+  liveOptions?: {
+    latencyMode: LiveVideoLatencyMode
+  }
 
   language?: string
 
@@ -250,21 +253,8 @@ export class PeertubePlayerOptionsBuilder {
                                                  .filter(t => t.startsWith('ws'))
 
     const specificLiveOrVODOptions = this.options.common.isLive
-      ? { // Live
-        requiredSegmentsPriority: 1
-      }
-      : { // VOD
-        requiredSegmentsPriority: 3,
-
-        cachedSegmentExpiration: 86400000,
-        cachedSegmentsCount: 100,
-
-        httpDownloadMaxPriority: 9,
-        httpDownloadProbability: 0.06,
-        httpDownloadProbabilitySkipIfNoPeers: true,
-
-        p2pDownloadMaxPriority: 50
-      }
+      ? this.getP2PMediaLoaderLiveOptions()
+      : this.getP2PMediaLoaderVODOptions()
 
     return {
       trackerAnnounce,
@@ -283,13 +273,57 @@ export class PeertubePlayerOptionsBuilder {
     }
   }
 
+  private getP2PMediaLoaderLiveOptions (): Partial<HybridLoaderSettings> {
+    const base = {
+      requiredSegmentsPriority: 1
+    }
+
+    const latencyMode = this.options.common.liveOptions.latencyMode
+
+    switch (latencyMode) {
+      case LiveVideoLatencyMode.SMALL_LATENCY:
+        return {
+          ...base,
+
+          useP2P: false,
+          httpDownloadProbability: 1
+        }
+
+      case LiveVideoLatencyMode.HIGH_LATENCY:
+        return base
+
+      default:
+        return base
+    }
+  }
+
+  private getP2PMediaLoaderVODOptions (): Partial<HybridLoaderSettings> {
+    return {
+      requiredSegmentsPriority: 3,
+
+      cachedSegmentExpiration: 86400000,
+      cachedSegmentsCount: 100,
+
+      httpDownloadMaxPriority: 9,
+      httpDownloadProbability: 0.06,
+      httpDownloadProbabilitySkipIfNoPeers: true,
+
+      p2pDownloadMaxPriority: 50
+    }
+  }
+
   private getHLSOptions (p2pMediaLoaderConfig: HlsJsEngineSettings) {
+    const specificLiveOrVODOptions = this.options.common.isLive
+      ? this.getHLSLiveOptions()
+      : this.getHLSVODOptions()
+
     const base = {
       capLevelToPlayerSize: true,
       autoStartLoad: false,
-      liveSyncDurationCount: 5,
 
-      loader: new this.p2pMediaLoaderModule.Engine(p2pMediaLoaderConfig).createLoaderClass()
+      loader: new this.p2pMediaLoaderModule.Engine(p2pMediaLoaderConfig).createLoaderClass(),
+
+      ...specificLiveOrVODOptions
     }
 
     const averageBandwidth = getAverageBandwidthInStore()
@@ -305,6 +339,33 @@ export class PeertubePlayerOptionsBuilder {
     }
   }
 
+  private getHLSLiveOptions () {
+    const latencyMode = this.options.common.liveOptions.latencyMode
+
+    switch (latencyMode) {
+      case LiveVideoLatencyMode.SMALL_LATENCY:
+        return {
+          liveSyncDurationCount: 2
+        }
+
+      case LiveVideoLatencyMode.HIGH_LATENCY:
+        return {
+          liveSyncDurationCount: 10
+        }
+
+      default:
+        return {
+          liveSyncDurationCount: 5
+        }
+    }
+  }
+
+  private getHLSVODOptions () {
+    return {
+      liveSyncDurationCount: 5
+    }
+  }
+
   private addWebTorrentOptions (plugins: VideoJSPluginOptions, alreadyPlayed: boolean) {
     const commonOptions = this.options.common
     const webtorrentOptions = this.options.webtorrent
diff --git a/client/src/standalone/videos/embed.ts b/client/src/standalone/videos/embed.ts
index 38ff39890..9e4d87911 100644
--- a/client/src/standalone/videos/embed.ts
+++ b/client/src/standalone/videos/embed.ts
@@ -6,6 +6,7 @@ import { peertubeTranslate } from '../../../../shared/core-utils/i18n'
 import {
   HTMLServerConfig,
   HttpStatusCode,
+  LiveVideo,
   OAuth2ErrorCode,
   ResultList,
   UserRefreshToken,
@@ -94,6 +95,10 @@ export class PeerTubeEmbed {
     return window.location.origin + '/api/v1/videos/' + id
   }
 
+  getLiveUrl (videoId: string) {
+    return window.location.origin + '/api/v1/videos/live/' + videoId
+  }
+
   refreshFetch (url: string, options?: RequestInit) {
     return fetch(url, options)
       .then((res: Response) => {
@@ -166,6 +171,12 @@ export class PeerTubeEmbed {
     return this.refreshFetch(this.getVideoUrl(videoId) + '/captions', { headers: this.headers })
   }
 
+  loadWithLive (video: VideoDetails) {
+    return this.refreshFetch(this.getLiveUrl(video.uuid), { headers: this.headers })
+      .then(res => res.json())
+      .then((live: LiveVideo) => ({ video, live }))
+  }
+
   loadPlaylistInfo (playlistId: string): Promise<Response> {
     return this.refreshFetch(this.getPlaylistUrl(playlistId), { headers: this.headers })
   }
@@ -475,13 +486,15 @@ export class PeerTubeEmbed {
         .then(res => res.json())
     }
 
-    const videoInfoPromise = videoResponse.json()
+    const videoInfoPromise: Promise<{ video: VideoDetails, live?: LiveVideo }> = videoResponse.json()
       .then((videoInfo: VideoDetails) => {
         this.loadParams(videoInfo)
 
-        if (!alreadyHadPlayer && !this.autoplay) this.loadPlaceholder(videoInfo)
+        if (!alreadyHadPlayer && !this.autoplay) this.buildPlaceholder(videoInfo)
 
-        return videoInfo
+        if (!videoInfo.isLive) return { video: videoInfo }
+
+        return this.loadWithLive(videoInfo)
       })
 
     const [ videoInfoTmp, serverTranslations, captionsResponse, PeertubePlayerManagerModule ] = await Promise.all([
@@ -493,11 +506,15 @@ export class PeerTubeEmbed {
 
     await this.loadPlugins(serverTranslations)
 
-    const videoInfo: VideoDetails = videoInfoTmp
+    const { video: videoInfo, live } = videoInfoTmp
 
     const PeertubePlayerManager = PeertubePlayerManagerModule.PeertubePlayerManager
     const videoCaptions = await this.buildCaptions(serverTranslations, captionsResponse)
 
+    const liveOptions = videoInfo.isLive
+      ? { latencyMode: live.latencyMode }
+      : undefined
+
     const playlistPlugin = this.currentPlaylistElement
       ? {
         elements: this.playlistElements,
@@ -545,6 +562,7 @@ export class PeerTubeEmbed {
         videoUUID: videoInfo.uuid,
 
         isLive: videoInfo.isLive,
+        liveOptions,
 
         playerElement: this.playerElement,
         onPlayerElementChange: (element: HTMLVideoElement) => {
@@ -726,7 +744,7 @@ export class PeerTubeEmbed {
     return []
   }
 
-  private loadPlaceholder (video: VideoDetails) {
+  private buildPlaceholder (video: VideoDetails) {
     const placeholder = this.getPlaceholderElement()
 
     const url = window.location.origin + video.previewPath
diff --git a/config/default.yaml b/config/default.yaml
index d76894b52..898395705 100644
--- a/config/default.yaml
+++ b/config/default.yaml
@@ -392,6 +392,12 @@ live:
   # /!\ transcoding.enabled (and not live.transcoding.enabled) has to be true to create a replay
   allow_replay: true
 
+  # Allow your users to change latency settings (small latency/default/high latency)
+  # Small latency live streams cannot use P2P
+  # High latency live streams can increase P2P ratio
+  latency_setting:
+    enabled: true
+
   # Your firewall should accept traffic from this port in TCP if you enable live
   rtmp:
     enabled: true
diff --git a/config/production.yaml.example b/config/production.yaml.example
index 45d26190a..03afe5841 100644
--- a/config/production.yaml.example
+++ b/config/production.yaml.example
@@ -400,6 +400,12 @@ live:
   # /!\ transcoding.enabled (and not live.transcoding.enabled) has to be true to create a replay
   allow_replay: true
 
+  # Allow your users to change latency settings (small latency/default/high latency)
+  # Small latency live streams cannot use P2P
+  # High latency live streams can increase P2P ratio
+  latency_setting:
+    enabled: true
+
   # Your firewall should accept traffic from this port in TCP if you enable live
   rtmp:
     enabled: true
diff --git a/server/controllers/api/config.ts b/server/controllers/api/config.ts
index 821ed4ad3..376143cb8 100644
--- a/server/controllers/api/config.ts
+++ b/server/controllers/api/config.ts
@@ -237,6 +237,9 @@ function customConfig (): CustomConfig {
     live: {
       enabled: CONFIG.LIVE.ENABLED,
       allowReplay: CONFIG.LIVE.ALLOW_REPLAY,
+      latencySetting: {
+        enabled: CONFIG.LIVE.LATENCY_SETTING.ENABLED
+      },
       maxDuration: CONFIG.LIVE.MAX_DURATION,
       maxInstanceLives: CONFIG.LIVE.MAX_INSTANCE_LIVES,
       maxUserLives: CONFIG.LIVE.MAX_USER_LIVES,
diff --git a/server/controllers/api/videos/live.ts b/server/controllers/api/videos/live.ts
index 49cabb6f3..c6f038079 100644
--- a/server/controllers/api/videos/live.ts
+++ b/server/controllers/api/videos/live.ts
@@ -1,4 +1,5 @@
 import express from 'express'
+import { exists } from '@server/helpers/custom-validators/misc'
 import { createReqFiles } from '@server/helpers/express-utils'
 import { ASSETS_PATH, MIMETYPES } from '@server/initializers/constants'
 import { getLocalVideoActivityPubUrl } from '@server/lib/activitypub/url'
@@ -9,7 +10,7 @@ import { videoLiveAddValidator, videoLiveGetValidator, videoLiveUpdateValidator
 import { VideoLiveModel } from '@server/models/video/video-live'
 import { MVideoDetails, MVideoFullLight } from '@server/types/models'
 import { buildUUID, uuidToShort } from '@shared/extra-utils'
-import { HttpStatusCode, LiveVideoCreate, LiveVideoUpdate, VideoState } from '@shared/models'
+import { HttpStatusCode, LiveVideoCreate, LiveVideoLatencyMode, LiveVideoUpdate, VideoState } from '@shared/models'
 import { logger } from '../../../helpers/logger'
 import { sequelizeTypescript } from '../../../initializers/database'
 import { updateVideoMiniatureFromExisting } from '../../../lib/thumbnail'
@@ -60,8 +61,9 @@ async function updateLiveVideo (req: express.Request, res: express.Response) {
   const video = res.locals.videoAll
   const videoLive = res.locals.videoLive
 
-  videoLive.saveReplay = body.saveReplay || false
-  videoLive.permanentLive = body.permanentLive || false
+  if (exists(body.saveReplay)) videoLive.saveReplay = body.saveReplay
+  if (exists(body.permanentLive)) videoLive.permanentLive = body.permanentLive
+  if (exists(body.latencyMode)) videoLive.latencyMode = body.latencyMode
 
   video.VideoLive = await videoLive.save()
 
@@ -87,6 +89,7 @@ async function addLiveVideo (req: express.Request, res: express.Response) {
   const videoLive = new VideoLiveModel()
   videoLive.saveReplay = videoInfo.saveReplay || false
   videoLive.permanentLive = videoInfo.permanentLive || false
+  videoLive.latencyMode = videoInfo.latencyMode || LiveVideoLatencyMode.DEFAULT
   videoLive.streamKey = buildUUID()
 
   const [ thumbnailModel, previewModel ] = await buildVideoThumbnailsFromReq({
diff --git a/server/helpers/activitypub.ts b/server/helpers/activitypub.ts
index cbba2f51c..d0bcc6785 100644
--- a/server/helpers/activitypub.ts
+++ b/server/helpers/activitypub.ts
@@ -50,6 +50,10 @@ function getContextData (type: ContextType) {
           '@type': 'sc:Boolean',
           '@id': 'pt:permanentLive'
         },
+        latencyMode: {
+          '@type': 'sc:Number',
+          '@id': 'pt:latencyMode'
+        },
 
         Infohash: 'pt:Infohash',
         Playlist: 'pt:Playlist',
diff --git a/server/helpers/custom-validators/activitypub/videos.ts b/server/helpers/custom-validators/activitypub/videos.ts
index a41d37810..80a321117 100644
--- a/server/helpers/custom-validators/activitypub/videos.ts
+++ b/server/helpers/custom-validators/activitypub/videos.ts
@@ -1,10 +1,11 @@
 import validator from 'validator'
 import { logger } from '@server/helpers/logger'
 import { ActivityTrackerUrlObject, ActivityVideoFileMetadataUrlObject } from '@shared/models'
-import { VideoState } from '../../../../shared/models/videos'
+import { LiveVideoLatencyMode, VideoState } from '../../../../shared/models/videos'
 import { ACTIVITY_PUB, CONSTRAINTS_FIELDS } from '../../../initializers/constants'
 import { peertubeTruncate } from '../../core-utils'
 import { exists, isArray, isBooleanValid, isDateValid, isUUIDValid } from '../misc'
+import { isLiveLatencyModeValid } from '../video-lives'
 import {
   isVideoDurationValid,
   isVideoNameValid,
@@ -65,6 +66,7 @@ function sanitizeAndCheckVideoTorrentObject (video: any) {
   if (!isBooleanValid(video.isLiveBroadcast)) video.isLiveBroadcast = false
   if (!isBooleanValid(video.liveSaveReplay)) video.liveSaveReplay = false
   if (!isBooleanValid(video.permanentLive)) video.permanentLive = false
+  if (!isLiveLatencyModeValid(video.latencyMode)) video.latencyMode = LiveVideoLatencyMode.DEFAULT
 
   return isActivityPubUrlValid(video.id) &&
     isVideoNameValid(video.name) &&
diff --git a/server/helpers/custom-validators/video-lives.ts b/server/helpers/custom-validators/video-lives.ts
new file mode 100644
index 000000000..69d08ae68
--- /dev/null
+++ b/server/helpers/custom-validators/video-lives.ts
@@ -0,0 +1,11 @@
+import { LiveVideoLatencyMode } from '@shared/models'
+
+function isLiveLatencyModeValid (value: any) {
+  return [ LiveVideoLatencyMode.DEFAULT, LiveVideoLatencyMode.SMALL_LATENCY, LiveVideoLatencyMode.HIGH_LATENCY ].includes(value)
+}
+
+// ---------------------------------------------------------------------------
+
+export {
+  isLiveLatencyModeValid
+}
diff --git a/server/helpers/ffmpeg/ffmpeg-live.ts b/server/helpers/ffmpeg/ffmpeg-live.ts
index ff571626c..fd20971eb 100644
--- a/server/helpers/ffmpeg/ffmpeg-live.ts
+++ b/server/helpers/ffmpeg/ffmpeg-live.ts
@@ -1,7 +1,7 @@
 import { FfmpegCommand, FilterSpecification } from 'fluent-ffmpeg'
 import { join } from 'path'
 import { VIDEO_LIVE } from '@server/initializers/constants'
-import { AvailableEncoders } from '@shared/models'
+import { AvailableEncoders, LiveVideoLatencyMode } from '@shared/models'
 import { logger, loggerTagsFactory } from '../logger'
 import { buildStreamSuffix, getFFmpeg, getScaleFilter, StreamType } from './ffmpeg-commons'
 import { getEncoderBuilderResult } from './ffmpeg-encoders'
@@ -15,6 +15,7 @@ async function getLiveTranscodingCommand (options: {
 
   outPath: string
   masterPlaylistName: string
+  latencyMode: LiveVideoLatencyMode
 
   resolutions: number[]
 
@@ -26,7 +27,7 @@ async function getLiveTranscodingCommand (options: {
   availableEncoders: AvailableEncoders
   profile: string
 }) {
-  const { inputUrl, outPath, resolutions, fps, bitrate, availableEncoders, profile, masterPlaylistName, ratio } = options
+  const { inputUrl, outPath, resolutions, fps, bitrate, availableEncoders, profile, masterPlaylistName, ratio, latencyMode } = options
 
   const command = getFFmpeg(inputUrl, 'live')
 
@@ -120,14 +121,21 @@ async function getLiveTranscodingCommand (options: {
 
   command.complexFilter(complexFilter)
 
-  addDefaultLiveHLSParams(command, outPath, masterPlaylistName)
+  addDefaultLiveHLSParams({ command, outPath, masterPlaylistName, latencyMode })
 
   command.outputOption('-var_stream_map', varStreamMap.join(' '))
 
   return command
 }
 
-function getLiveMuxingCommand (inputUrl: string, outPath: string, masterPlaylistName: string) {
+function getLiveMuxingCommand (options: {
+  inputUrl: string
+  outPath: string
+  masterPlaylistName: string
+  latencyMode: LiveVideoLatencyMode
+}) {
+  const { inputUrl, outPath, masterPlaylistName, latencyMode } = options
+
   const command = getFFmpeg(inputUrl, 'live')
 
   command.outputOption('-c:v copy')
@@ -135,22 +143,39 @@ function getLiveMuxingCommand (inputUrl: string, outPath: string, masterPlaylist
   command.outputOption('-map 0:a?')
   command.outputOption('-map 0:v?')
 
-  addDefaultLiveHLSParams(command, outPath, masterPlaylistName)
+  addDefaultLiveHLSParams({ command, outPath, masterPlaylistName, latencyMode })
 
   return command
 }
 
+function getLiveSegmentTime (latencyMode: LiveVideoLatencyMode) {
+  if (latencyMode === LiveVideoLatencyMode.SMALL_LATENCY) {
+    return VIDEO_LIVE.SEGMENT_TIME_SECONDS.SMALL_LATENCY
+  }
+
+  return VIDEO_LIVE.SEGMENT_TIME_SECONDS.DEFAULT_LATENCY
+}
+
 // ---------------------------------------------------------------------------
 
 export {
+  getLiveSegmentTime,
+
   getLiveTranscodingCommand,
   getLiveMuxingCommand
 }
 
 // ---------------------------------------------------------------------------
 
-function addDefaultLiveHLSParams (command: FfmpegCommand, outPath: string, masterPlaylistName: string) {
-  command.outputOption('-hls_time ' + VIDEO_LIVE.SEGMENT_TIME_SECONDS)
+function addDefaultLiveHLSParams (options: {
+  command: FfmpegCommand
+  outPath: string
+  masterPlaylistName: string
+  latencyMode: LiveVideoLatencyMode
+}) {
+  const { command, outPath, masterPlaylistName, latencyMode } = options
+
+  command.outputOption('-hls_time ' + getLiveSegmentTime(latencyMode))
   command.outputOption('-hls_list_size ' + VIDEO_LIVE.SEGMENTS_LIST_SIZE)
   command.outputOption('-hls_flags delete_segments+independent_segments')
   command.outputOption(`-hls_segment_filename ${join(outPath, '%v-%06d.ts')}`)
diff --git a/server/initializers/checker-before-init.ts b/server/initializers/checker-before-init.ts
index 10dd98f43..fa311f708 100644
--- a/server/initializers/checker-before-init.ts
+++ b/server/initializers/checker-before-init.ts
@@ -49,8 +49,8 @@ function checkMissedConfig () {
     'peertube.check_latest_version.enabled', 'peertube.check_latest_version.url',
     'search.remote_uri.users', 'search.remote_uri.anonymous', 'search.search_index.enabled', 'search.search_index.url',
     'search.search_index.disable_local_search', 'search.search_index.is_default_search',
-    'live.enabled', 'live.allow_replay', 'live.max_duration', 'live.max_user_lives', 'live.max_instance_lives',
-    'live.rtmp.enabled', 'live.rtmp.port', 'live.rtmp.hostname',
+    'live.enabled', 'live.allow_replay', 'live.latency_setting.enabled', 'live.max_duration',
+    'live.max_user_lives', 'live.max_instance_lives', 'live.rtmp.enabled', 'live.rtmp.port', 'live.rtmp.hostname',
     'live.rtmps.enabled', 'live.rtmps.port', 'live.rtmps.hostname', 'live.rtmps.key_file', 'live.rtmps.cert_file',
     'live.transcoding.enabled', 'live.transcoding.threads', 'live.transcoding.profile',
     'live.transcoding.resolutions.144p', 'live.transcoding.resolutions.240p', 'live.transcoding.resolutions.360p',
diff --git a/server/initializers/config.ts b/server/initializers/config.ts
index 7a13a1368..6dcca9b67 100644
--- a/server/initializers/config.ts
+++ b/server/initializers/config.ts
@@ -4,9 +4,9 @@ import { dirname, join } from 'path'
 import { decacheModule } from '@server/helpers/decache'
 import { VideoRedundancyConfigFilter } from '@shared/models/redundancy/video-redundancy-config-filter.type'
 import { BroadcastMessageLevel } from '@shared/models/server'
+import { buildPath, root } from '../../shared/core-utils'
 import { VideoPrivacy, VideosRedundancyStrategy } from '../../shared/models'
 import { NSFWPolicyType } from '../../shared/models/videos/nsfw-policy.type'
-import { buildPath, root } from '../../shared/core-utils'
 import { parseBytes, parseDurationToMs } from '../helpers/core-utils'
 
 // Use a variable to reload the configuration if we need
@@ -296,6 +296,10 @@ const CONFIG = {
 
     get ALLOW_REPLAY () { return config.get<boolean>('live.allow_replay') },
 
+    LATENCY_SETTING: {
+      get ENABLED () { return config.get<boolean>('live.latency_setting.enabled') }
+    },
+
     RTMP: {
       get ENABLED () { return config.get<boolean>('live.rtmp.enabled') },
       get PORT () { return config.get<number>('live.rtmp.port') },
diff --git a/server/initializers/constants.ts b/server/initializers/constants.ts
index 7bc2877aa..1c849b561 100644
--- a/server/initializers/constants.ts
+++ b/server/initializers/constants.ts
@@ -24,7 +24,7 @@ import { CONFIG, registerConfigChangedHandler } from './config'
 
 // ---------------------------------------------------------------------------
 
-const LAST_MIGRATION_VERSION = 685
+const LAST_MIGRATION_VERSION = 690
 
 // ---------------------------------------------------------------------------
 
@@ -700,7 +700,10 @@ const RESUMABLE_UPLOAD_SESSION_LIFETIME = SCHEDULER_INTERVALS_MS.REMOVE_DANGLING
 const VIDEO_LIVE = {
   EXTENSION: '.ts',
   CLEANUP_DELAY: 1000 * 60 * 5, // 5 minutes
-  SEGMENT_TIME_SECONDS: 4, // 4 seconds
+  SEGMENT_TIME_SECONDS: {
+    DEFAULT_LATENCY: 4, // 4 seconds
+    SMALL_LATENCY: 2 // 2 seconds
+  },
   SEGMENTS_LIST_SIZE: 15, // 15 maximum segments in live playlist
   REPLAY_DIRECTORY: 'replay',
   EDGE_LIVE_DELAY_SEGMENTS_NOTIFICATION: 4,
@@ -842,7 +845,8 @@ if (isTestInstance() === true) {
   PLUGIN_EXTERNAL_AUTH_TOKEN_LIFETIME = 5000
 
   VIDEO_LIVE.CLEANUP_DELAY = 5000
-  VIDEO_LIVE.SEGMENT_TIME_SECONDS = 2
+  VIDEO_LIVE.SEGMENT_TIME_SECONDS.DEFAULT_LATENCY = 2
+  VIDEO_LIVE.SEGMENT_TIME_SECONDS.SMALL_LATENCY = 1
   VIDEO_LIVE.EDGE_LIVE_DELAY_SEGMENTS_NOTIFICATION = 1
 }
 
diff --git a/server/initializers/migrations/0690-live-latency-mode.ts b/server/initializers/migrations/0690-live-latency-mode.ts
new file mode 100644
index 000000000..c31a61364
--- /dev/null
+++ b/server/initializers/migrations/0690-live-latency-mode.ts
@@ -0,0 +1,35 @@
+import { LiveVideoLatencyMode } from '@shared/models'
+import * as Sequelize from 'sequelize'
+
+async function up (utils: {
+  transaction: Sequelize.Transaction
+  queryInterface: Sequelize.QueryInterface
+  sequelize: Sequelize.Sequelize
+  db: any
+}): Promise<void> {
+  await utils.queryInterface.addColumn('videoLive', 'latencyMode', {
+    type: Sequelize.INTEGER,
+    defaultValue: null,
+    allowNull: true
+  }, { transaction: utils.transaction })
+
+  {
+    const query = `UPDATE "videoLive" SET "latencyMode" = ${LiveVideoLatencyMode.DEFAULT}`
+    await utils.sequelize.query(query, { type: Sequelize.QueryTypes.UPDATE, transaction: utils.transaction })
+  }
+
+  await utils.queryInterface.changeColumn('videoLive', 'latencyMode', {
+    type: Sequelize.INTEGER,
+    defaultValue: null,
+    allowNull: false
+  }, { transaction: utils.transaction })
+}
+
+function down () {
+  throw new Error('Not implemented.')
+}
+
+export {
+  up,
+  down
+}
diff --git a/server/lib/activitypub/videos/shared/object-to-model-attributes.ts b/server/lib/activitypub/videos/shared/object-to-model-attributes.ts
index 1e1479869..c97217669 100644
--- a/server/lib/activitypub/videos/shared/object-to-model-attributes.ts
+++ b/server/lib/activitypub/videos/shared/object-to-model-attributes.ts
@@ -151,6 +151,7 @@ function getLiveAttributesFromObject (video: MVideoId, videoObject: VideoObject)
   return {
     saveReplay: videoObject.liveSaveReplay,
     permanentLive: videoObject.permanentLive,
+    latencyMode: videoObject.latencyMode,
     videoId: video.id
   }
 }
diff --git a/server/lib/live/live-manager.ts b/server/lib/live/live-manager.ts
index 21c34a9a4..920d3a5ec 100644
--- a/server/lib/live/live-manager.ts
+++ b/server/lib/live/live-manager.ts
@@ -5,9 +5,10 @@ import { createServer as createServerTLS, Server as ServerTLS } from 'tls'
 import {
   computeLowerResolutionsToTranscode,
   ffprobePromise,
+  getLiveSegmentTime,
   getVideoStreamBitrate,
-  getVideoStreamFPS,
-  getVideoStreamDimensionsInfo
+  getVideoStreamDimensionsInfo,
+  getVideoStreamFPS
 } from '@server/helpers/ffmpeg'
 import { logger, loggerTagsFactory } from '@server/helpers/logger'
 import { CONFIG, registerConfigChangedHandler } from '@server/initializers/config'
@@ -353,7 +354,7 @@ class LiveManager {
           .catch(err => logger.error('Cannot federate live video %s.', video.url, { err, ...localLTags }))
 
         PeerTubeSocket.Instance.sendVideoLiveNewState(video)
-      }, VIDEO_LIVE.SEGMENT_TIME_SECONDS * 1000 * VIDEO_LIVE.EDGE_LIVE_DELAY_SEGMENTS_NOTIFICATION)
+      }, getLiveSegmentTime(live.latencyMode) * 1000 * VIDEO_LIVE.EDGE_LIVE_DELAY_SEGMENTS_NOTIFICATION)
     } catch (err) {
       logger.error('Cannot save/federate live video %d.', videoId, { err, ...localLTags })
     }
diff --git a/server/lib/live/shared/muxing-session.ts b/server/lib/live/shared/muxing-session.ts
index f5f473039..a703f5b5f 100644
--- a/server/lib/live/shared/muxing-session.ts
+++ b/server/lib/live/shared/muxing-session.ts
@@ -125,6 +125,8 @@ class MuxingSession extends EventEmitter {
         outPath,
         masterPlaylistName: this.streamingPlaylist.playlistFilename,
 
+        latencyMode: this.videoLive.latencyMode,
+
         resolutions: this.allResolutions,
         fps: this.fps,
         bitrate: this.bitrate,
@@ -133,7 +135,12 @@ class MuxingSession extends EventEmitter {
         availableEncoders: VideoTranscodingProfilesManager.Instance.getAvailableEncoders(),
         profile: CONFIG.LIVE.TRANSCODING.PROFILE
       })
-      : getLiveMuxingCommand(this.inputUrl, outPath, this.streamingPlaylist.playlistFilename)
+      : getLiveMuxingCommand({
+        inputUrl: this.inputUrl,
+        outPath,
+        masterPlaylistName: this.streamingPlaylist.playlistFilename,
+        latencyMode: this.videoLive.latencyMode
+      })
 
     logger.info('Running live muxing/transcoding for %s.', this.videoUUID, this.lTags())
 
diff --git a/server/lib/server-config-manager.ts b/server/lib/server-config-manager.ts
index 43ca2332b..744186cfc 100644
--- a/server/lib/server-config-manager.ts
+++ b/server/lib/server-config-manager.ts
@@ -137,6 +137,10 @@ class ServerConfigManager {
         enabled: CONFIG.LIVE.ENABLED,
 
         allowReplay: CONFIG.LIVE.ALLOW_REPLAY,
+        latencySetting: {
+          enabled: CONFIG.LIVE.LATENCY_SETTING.ENABLED
+        },
+
         maxDuration: CONFIG.LIVE.MAX_DURATION,
         maxInstanceLives: CONFIG.LIVE.MAX_INSTANCE_LIVES,
         maxUserLives: CONFIG.LIVE.MAX_USER_LIVES,
diff --git a/server/middlewares/validators/videos/video-live.ts b/server/middlewares/validators/videos/video-live.ts
index 6c7601e05..8e52c953f 100644
--- a/server/middlewares/validators/videos/video-live.ts
+++ b/server/middlewares/validators/videos/video-live.ts
@@ -1,12 +1,21 @@
 import express from 'express'
 import { body } from 'express-validator'
+import { isLiveLatencyModeValid } from '@server/helpers/custom-validators/video-lives'
 import { CONSTRAINTS_FIELDS } from '@server/initializers/constants'
 import { isLocalLiveVideoAccepted } from '@server/lib/moderation'
 import { Hooks } from '@server/lib/plugins/hooks'
 import { VideoModel } from '@server/models/video/video'
 import { VideoLiveModel } from '@server/models/video/video-live'
-import { HttpStatusCode, ServerErrorCode, UserRight, VideoState } from '@shared/models'
-import { isBooleanValid, isIdValid, toBooleanOrNull, toIntOrNull } from '../../../helpers/custom-validators/misc'
+import {
+  HttpStatusCode,
+  LiveVideoCreate,
+  LiveVideoLatencyMode,
+  LiveVideoUpdate,
+  ServerErrorCode,
+  UserRight,
+  VideoState
+} from '@shared/models'
+import { exists, isBooleanValid, isIdValid, toBooleanOrNull, toIntOrNull } from '../../../helpers/custom-validators/misc'
 import { isVideoNameValid } from '../../../helpers/custom-validators/videos'
 import { cleanUpReqFiles } from '../../../helpers/express-utils'
 import { logger } from '../../../helpers/logger'
@@ -67,6 +76,12 @@ const videoLiveAddValidator = getCommonVideoEditAttributes().concat([
     .customSanitizer(toBooleanOrNull)
     .custom(isBooleanValid).withMessage('Should have a valid permanentLive attribute'),
 
+  body('latencyMode')
+    .optional()
+    .customSanitizer(toIntOrNull)
+    .custom(isLiveLatencyModeValid)
+    .withMessage('Should have a valid latency mode attribute'),
+
   async (req: express.Request, res: express.Response, next: express.NextFunction) => {
     logger.debug('Checking videoLiveAddValidator parameters', { parameters: req.body })
 
@@ -82,7 +97,9 @@ const videoLiveAddValidator = getCommonVideoEditAttributes().concat([
       })
     }
 
-    if (CONFIG.LIVE.ALLOW_REPLAY !== true && req.body.saveReplay === true) {
+    const body: LiveVideoCreate = req.body
+
+    if (hasValidSaveReplay(body) !== true) {
       cleanUpReqFiles(req)
 
       return res.fail({
@@ -92,14 +109,23 @@ const videoLiveAddValidator = getCommonVideoEditAttributes().concat([
       })
     }
 
-    if (req.body.permanentLive && req.body.saveReplay) {
+    if (hasValidLatencyMode(body) !== true) {
+      cleanUpReqFiles(req)
+
+      return res.fail({
+        status: HttpStatusCode.FORBIDDEN_403,
+        message: 'Custom latency mode is not allowed by this instance'
+      })
+    }
+
+    if (body.permanentLive && body.saveReplay) {
       cleanUpReqFiles(req)
 
       return res.fail({ message: 'Cannot set this live as permanent while saving its replay' })
     }
 
     const user = res.locals.oauth.token.User
-    if (!await doesVideoChannelOfAccountExist(req.body.channelId, user, res)) return cleanUpReqFiles(req)
+    if (!await doesVideoChannelOfAccountExist(body.channelId, user, res)) return cleanUpReqFiles(req)
 
     if (CONFIG.LIVE.MAX_INSTANCE_LIVES !== -1) {
       const totalInstanceLives = await VideoModel.countLocalLives()
@@ -141,19 +167,34 @@ const videoLiveUpdateValidator = [
     .customSanitizer(toBooleanOrNull)
     .custom(isBooleanValid).withMessage('Should have a valid saveReplay attribute'),
 
+  body('latencyMode')
+    .optional()
+    .customSanitizer(toIntOrNull)
+    .custom(isLiveLatencyModeValid)
+    .withMessage('Should have a valid latency mode attribute'),
+
   (req: express.Request, res: express.Response, next: express.NextFunction) => {
     logger.debug('Checking videoLiveUpdateValidator parameters', { parameters: req.body })
 
     if (areValidationErrors(req, res)) return
 
-    if (req.body.permanentLive && req.body.saveReplay) {
+    const body: LiveVideoUpdate = req.body
+
+    if (body.permanentLive && body.saveReplay) {
       return res.fail({ message: 'Cannot set this live as permanent while saving its replay' })
     }
 
-    if (CONFIG.LIVE.ALLOW_REPLAY !== true && req.body.saveReplay === true) {
+    if (hasValidSaveReplay(body) !== true) {
       return res.fail({
         status: HttpStatusCode.FORBIDDEN_403,
-        message: 'Saving live replay is not allowed instance'
+        message: 'Saving live replay is not allowed by this instance'
+      })
+    }
+
+    if (hasValidLatencyMode(body) !== true) {
+      return res.fail({
+        status: HttpStatusCode.FORBIDDEN_403,
+        message: 'Custom latency mode is not allowed by this instance'
       })
     }
 
@@ -203,3 +244,19 @@ async function isLiveVideoAccepted (req: express.Request, res: express.Response)
 
   return true
 }
+
+function hasValidSaveReplay (body: LiveVideoUpdate | LiveVideoCreate) {
+  if (CONFIG.LIVE.ALLOW_REPLAY !== true && body.saveReplay === true) return false
+
+  return true
+}
+
+function hasValidLatencyMode (body: LiveVideoUpdate | LiveVideoCreate) {
+  if (
+    CONFIG.LIVE.LATENCY_SETTING.ENABLED !== true &&
+    exists(body.latencyMode) &&
+    body.latencyMode !== LiveVideoLatencyMode.DEFAULT
+  ) return false
+
+  return true
+}
diff --git a/server/models/video/formatter/video-format-utils.ts b/server/models/video/formatter/video-format-utils.ts
index 7456f37c5..611edf0b9 100644
--- a/server/models/video/formatter/video-format-utils.ts
+++ b/server/models/video/formatter/video-format-utils.ts
@@ -411,15 +411,6 @@ function videoModelToActivityPubObject (video: MVideoAP): VideoObject {
     views: video.views,
     sensitive: video.nsfw,
     waitTranscoding: video.waitTranscoding,
-    isLiveBroadcast: video.isLive,
-
-    liveSaveReplay: video.isLive
-      ? video.VideoLive.saveReplay
-      : null,
-
-    permanentLive: video.isLive
-      ? video.VideoLive.permanentLive
-      : null,
 
     state: video.state,
     commentsEnabled: video.commentsEnabled,
@@ -431,10 +422,13 @@ function videoModelToActivityPubObject (video: MVideoAP): VideoObject {
       : null,
 
     updated: video.updatedAt.toISOString(),
+
     mediaType: 'text/markdown',
     content: video.description,
     support: video.support,
+
     subtitleLanguage,
+
     icon: icons.map(i => ({
       type: 'Image',
       url: i.getFileUrl(video),
@@ -442,11 +436,14 @@ function videoModelToActivityPubObject (video: MVideoAP): VideoObject {
       width: i.width,
       height: i.height
     })),
+
     url,
+
     likes: getLocalVideoLikesActivityPubUrl(video),
     dislikes: getLocalVideoDislikesActivityPubUrl(video),
     shares: getLocalVideoSharesActivityPubUrl(video),
     comments: getLocalVideoCommentsActivityPubUrl(video),
+
     attributedTo: [
       {
         type: 'Person',
@@ -456,7 +453,9 @@ function videoModelToActivityPubObject (video: MVideoAP): VideoObject {
         type: 'Group',
         id: video.VideoChannel.Actor.url
       }
-    ]
+    ],
+
+    ...buildLiveAPAttributes(video)
   }
 }
 
@@ -500,3 +499,23 @@ export {
   getPrivacyLabel,
   getStateLabel
 }
+
+// ---------------------------------------------------------------------------
+
+function buildLiveAPAttributes (video: MVideoAP) {
+  if (!video.isLive) {
+    return {
+      isLiveBroadcast: false,
+      liveSaveReplay: null,
+      permanentLive: null,
+      latencyMode: null
+    }
+  }
+
+  return {
+    isLiveBroadcast: true,
+    liveSaveReplay: video.VideoLive.saveReplay,
+    permanentLive: video.VideoLive.permanentLive,
+    latencyMode: video.VideoLive.latencyMode
+  }
+}
diff --git a/server/models/video/sql/video/shared/video-table-attributes.ts b/server/models/video/sql/video/shared/video-table-attributes.ts
index f4d9e99fd..e2c1c0f6d 100644
--- a/server/models/video/sql/video/shared/video-table-attributes.ts
+++ b/server/models/video/sql/video/shared/video-table-attributes.ts
@@ -158,6 +158,7 @@ export class VideoTableAttributes {
       'streamKey',
       'saveReplay',
       'permanentLive',
+      'latencyMode',
       'videoId',
       'createdAt',
       'updatedAt'
diff --git a/server/models/video/video-live.ts b/server/models/video/video-live.ts
index e3fdcc0ba..904f712b4 100644
--- a/server/models/video/video-live.ts
+++ b/server/models/video/video-live.ts
@@ -1,11 +1,11 @@
 import { AllowNull, BelongsTo, Column, CreatedAt, DataType, DefaultScope, ForeignKey, Model, Table, UpdatedAt } from 'sequelize-typescript'
+import { CONFIG } from '@server/initializers/config'
 import { WEBSERVER } from '@server/initializers/constants'
 import { MVideoLive, MVideoLiveVideo } from '@server/types/models'
+import { LiveVideo, LiveVideoLatencyMode, VideoState } from '@shared/models'
 import { AttributesOnly } from '@shared/typescript-utils'
-import { LiveVideo, VideoState } from '@shared/models'
 import { VideoModel } from './video'
 import { VideoBlacklistModel } from './video-blacklist'
-import { CONFIG } from '@server/initializers/config'
 
 @DefaultScope(() => ({
   include: [
@@ -44,6 +44,10 @@ export class VideoLiveModel extends Model<Partial<AttributesOnly<VideoLiveModel>
   @Column
   permanentLive: boolean
 
+  @AllowNull(false)
+  @Column
+  latencyMode: LiveVideoLatencyMode
+
   @CreatedAt
   createdAt: Date
 
@@ -113,7 +117,8 @@ export class VideoLiveModel extends Model<Partial<AttributesOnly<VideoLiveModel>
 
       streamKey: this.streamKey,
       permanentLive: this.permanentLive,
-      saveReplay: this.saveReplay
+      saveReplay: this.saveReplay,
+      latencyMode: this.latencyMode
     }
   }
 }
diff --git a/server/tests/api/check-params/config.ts b/server/tests/api/check-params/config.ts
index ce067a892..900f642c2 100644
--- a/server/tests/api/check-params/config.ts
+++ b/server/tests/api/check-params/config.ts
@@ -125,6 +125,9 @@ describe('Test config API validators', function () {
       enabled: true,
 
       allowReplay: false,
+      latencySetting: {
+        enabled: false
+      },
       maxDuration: 30,
       maxInstanceLives: -1,
       maxUserLives: 50,
diff --git a/server/tests/api/check-params/live.ts b/server/tests/api/check-params/live.ts
index 8aee6164c..b253f5e20 100644
--- a/server/tests/api/check-params/live.ts
+++ b/server/tests/api/check-params/live.ts
@@ -3,7 +3,7 @@
 import 'mocha'
 import { omit } from 'lodash'
 import { buildAbsoluteFixturePath } from '@shared/core-utils'
-import { HttpStatusCode, VideoCreateResult, VideoPrivacy } from '@shared/models'
+import { HttpStatusCode, LiveVideoLatencyMode, VideoCreateResult, VideoPrivacy } from '@shared/models'
 import {
   cleanupTests,
   createSingleServer,
@@ -38,6 +38,9 @@ describe('Test video lives API validator', function () {
       newConfig: {
         live: {
           enabled: true,
+          latencySetting: {
+            enabled: false
+          },
           maxInstanceLives: 20,
           maxUserLives: 20,
           allowReplay: true
@@ -81,7 +84,8 @@ describe('Test video lives API validator', function () {
         privacy: VideoPrivacy.PUBLIC,
         channelId,
         saveReplay: false,
-        permanentLive: false
+        permanentLive: false,
+        latencyMode: LiveVideoLatencyMode.DEFAULT
       }
     })
 
@@ -214,6 +218,18 @@ describe('Test video lives API validator', function () {
       await makePostBodyRequest({ url: server.url, path, token: server.accessToken, fields })
     })
 
+    it('Should fail with bad latency setting', async function () {
+      const fields = { ...baseCorrectParams, latencyMode: 42 }
+
+      await makePostBodyRequest({ url: server.url, path, token: server.accessToken, fields })
+    })
+
+    it('Should fail to set latency if the server does not allow it', async function () {
+      const fields = { ...baseCorrectParams, latencyMode: LiveVideoLatencyMode.HIGH_LATENCY }
+
+      await makePostBodyRequest({ url: server.url, path, token: server.accessToken, fields, expectedStatus: HttpStatusCode.FORBIDDEN_403 })
+    })
+
     it('Should succeed with the correct parameters', async function () {
       this.timeout(30000)
 
@@ -393,6 +409,18 @@ describe('Test video lives API validator', function () {
       await command.update({ videoId: video.id, fields, expectedStatus: HttpStatusCode.BAD_REQUEST_400 })
     })
 
+    it('Should fail with bad latency setting', async function () {
+      const fields = { latencyMode: 42 }
+
+      await command.update({ videoId: video.id, fields, expectedStatus: HttpStatusCode.BAD_REQUEST_400 })
+    })
+
+    it('Should fail to set latency if the server does not allow it', async function () {
+      const fields = { latencyMode: LiveVideoLatencyMode.HIGH_LATENCY }
+
+      await command.update({ videoId: video.id, fields, expectedStatus: HttpStatusCode.FORBIDDEN_403 })
+    })
+
     it('Should succeed with the correct params', async function () {
       await command.update({ videoId: video.id, fields: { saveReplay: false } })
       await command.update({ videoId: video.uuid, fields: { saveReplay: false } })
diff --git a/server/tests/api/live/live.ts b/server/tests/api/live/live.ts
index d756a02c1..aeb039696 100644
--- a/server/tests/api/live/live.ts
+++ b/server/tests/api/live/live.ts
@@ -10,6 +10,7 @@ import {
   HttpStatusCode,
   LiveVideo,
   LiveVideoCreate,
+  LiveVideoLatencyMode,
   VideoDetails,
   VideoPrivacy,
   VideoState,
@@ -52,6 +53,9 @@ describe('Test live', function () {
         live: {
           enabled: true,
           allowReplay: true,
+          latencySetting: {
+            enabled: true
+          },
           transcoding: {
             enabled: false
           }
@@ -85,6 +89,7 @@ describe('Test live', function () {
         commentsEnabled: false,
         downloadEnabled: false,
         saveReplay: true,
+        latencyMode: LiveVideoLatencyMode.SMALL_LATENCY,
         privacy: VideoPrivacy.PUBLIC,
         previewfile: 'video_short1-preview.webm.jpg',
         thumbnailfile: 'video_short1.webm.jpg'
@@ -131,6 +136,7 @@ describe('Test live', function () {
         }
 
         expect(live.saveReplay).to.be.true
+        expect(live.latencyMode).to.equal(LiveVideoLatencyMode.SMALL_LATENCY)
       }
     })
 
@@ -175,7 +181,7 @@ describe('Test live', function () {
     it('Should update the live', async function () {
       this.timeout(10000)
 
-      await commands[0].update({ videoId: liveVideoUUID, fields: { saveReplay: false } })
+      await commands[0].update({ videoId: liveVideoUUID, fields: { saveReplay: false, latencyMode: LiveVideoLatencyMode.DEFAULT } })
       await waitJobs(servers)
     })
 
@@ -192,6 +198,7 @@ describe('Test live', function () {
         }
 
         expect(live.saveReplay).to.be.false
+        expect(live.latencyMode).to.equal(LiveVideoLatencyMode.DEFAULT)
       }
     })
 
diff --git a/server/tests/api/server/config.ts b/server/tests/api/server/config.ts
index 565b2953a..5028b65e6 100644
--- a/server/tests/api/server/config.ts
+++ b/server/tests/api/server/config.ts
@@ -82,6 +82,7 @@ function checkInitialConfig (server: PeerTubeServer, data: CustomConfig) {
 
   expect(data.live.enabled).to.be.false
   expect(data.live.allowReplay).to.be.false
+  expect(data.live.latencySetting.enabled).to.be.true
   expect(data.live.maxDuration).to.equal(-1)
   expect(data.live.maxInstanceLives).to.equal(20)
   expect(data.live.maxUserLives).to.equal(3)
@@ -185,6 +186,7 @@ function checkUpdatedConfig (data: CustomConfig) {
 
   expect(data.live.enabled).to.be.true
   expect(data.live.allowReplay).to.be.true
+  expect(data.live.latencySetting.enabled).to.be.false
   expect(data.live.maxDuration).to.equal(5000)
   expect(data.live.maxInstanceLives).to.equal(-1)
   expect(data.live.maxUserLives).to.equal(10)
@@ -326,6 +328,9 @@ const newCustomConfig: CustomConfig = {
   live: {
     enabled: true,
     allowReplay: true,
+    latencySetting: {
+      enabled: false
+    },
     maxDuration: 5000,
     maxInstanceLives: -1,
     maxUserLives: 10,
diff --git a/shared/models/activitypub/objects/video-torrent-object.ts b/shared/models/activitypub/objects/video-torrent-object.ts
index 9faa3bb87..23d54bdbd 100644
--- a/shared/models/activitypub/objects/video-torrent-object.ts
+++ b/shared/models/activitypub/objects/video-torrent-object.ts
@@ -5,7 +5,7 @@ import {
   ActivityTagObject,
   ActivityUrlObject
 } from './common-objects'
-import { VideoState } from '../../videos'
+import { LiveVideoLatencyMode, VideoState } from '../../videos'
 
 export interface VideoObject {
   type: 'Video'
@@ -25,6 +25,7 @@ export interface VideoObject {
   isLiveBroadcast: boolean
   liveSaveReplay: boolean
   permanentLive: boolean
+  latencyMode: LiveVideoLatencyMode
 
   commentsEnabled: boolean
   downloadEnabled: boolean
diff --git a/shared/models/server/custom-config.model.ts b/shared/models/server/custom-config.model.ts
index c9e7654de..5df606566 100644
--- a/shared/models/server/custom-config.model.ts
+++ b/shared/models/server/custom-config.model.ts
@@ -131,6 +131,10 @@ export interface CustomConfig {
 
     allowReplay: boolean
 
+    latencySetting: {
+      enabled: boolean
+    }
+
     maxDuration: number
     maxInstanceLives: number
     maxUserLives: number
diff --git a/shared/models/server/server-config.model.ts b/shared/models/server/server-config.model.ts
index b06019bb8..d7fbed13c 100644
--- a/shared/models/server/server-config.model.ts
+++ b/shared/models/server/server-config.model.ts
@@ -149,10 +149,14 @@ export interface ServerConfig {
   live: {
     enabled: boolean
 
+    allowReplay: boolean
+    latencySetting: {
+      enabled: boolean
+    }
+
     maxDuration: number
     maxInstanceLives: number
     maxUserLives: number
-    allowReplay: boolean
 
     transcoding: {
       enabled: boolean
diff --git a/shared/models/videos/live/index.ts b/shared/models/videos/live/index.ts
index a36f42a7d..68f32092a 100644
--- a/shared/models/videos/live/index.ts
+++ b/shared/models/videos/live/index.ts
@@ -1,5 +1,6 @@
 export * from './live-video-create.model'
 export * from './live-video-event-payload.model'
 export * from './live-video-event.type'
+export * from './live-video-latency-mode.enum'
 export * from './live-video-update.model'
 export * from './live-video.model'
diff --git a/shared/models/videos/live/live-video-create.model.ts b/shared/models/videos/live/live-video-create.model.ts
index caa7acc17..49ccaf45b 100644
--- a/shared/models/videos/live/live-video-create.model.ts
+++ b/shared/models/videos/live/live-video-create.model.ts
@@ -1,6 +1,8 @@
+import { LiveVideoLatencyMode } from '.'
 import { VideoCreate } from '../video-create.model'
 
 export interface LiveVideoCreate extends VideoCreate {
   saveReplay?: boolean
   permanentLive?: boolean
+  latencyMode?: LiveVideoLatencyMode
 }
diff --git a/shared/models/videos/live/live-video-latency-mode.enum.ts b/shared/models/videos/live/live-video-latency-mode.enum.ts
new file mode 100644
index 000000000..4285e1d41
--- /dev/null
+++ b/shared/models/videos/live/live-video-latency-mode.enum.ts
@@ -0,0 +1,5 @@
+export const enum LiveVideoLatencyMode {
+  DEFAULT = 1,
+  HIGH_LATENCY = 2,
+  SMALL_LATENCY = 3
+}
diff --git a/shared/models/videos/live/live-video-update.model.ts b/shared/models/videos/live/live-video-update.model.ts
index a39c44797..93bb4d30d 100644
--- a/shared/models/videos/live/live-video-update.model.ts
+++ b/shared/models/videos/live/live-video-update.model.ts
@@ -1,4 +1,7 @@
+import { LiveVideoLatencyMode } from './live-video-latency-mode.enum'
+
 export interface LiveVideoUpdate {
   permanentLive?: boolean
   saveReplay?: boolean
+  latencyMode?: LiveVideoLatencyMode
 }
diff --git a/shared/models/videos/live/live-video.model.ts b/shared/models/videos/live/live-video.model.ts
index 815a93804..2d3169941 100644
--- a/shared/models/videos/live/live-video.model.ts
+++ b/shared/models/videos/live/live-video.model.ts
@@ -1,8 +1,12 @@
+import { LiveVideoLatencyMode } from './live-video-latency-mode.enum'
+
 export interface LiveVideo {
   rtmpUrl: string
   rtmpsUrl: string
 
   streamKey: string
+
   saveReplay: boolean
   permanentLive: boolean
+  latencyMode: LiveVideoLatencyMode
 }
diff --git a/shared/server-commands/server/config-command.ts b/shared/server-commands/server/config-command.ts
index c0042060b..e47a0d346 100644
--- a/shared/server-commands/server/config-command.ts
+++ b/shared/server-commands/server/config-command.ts
@@ -292,6 +292,9 @@ export class ConfigCommand extends AbstractCommand {
       live: {
         enabled: true,
         allowReplay: false,
+        latencySetting: {
+          enabled: false
+        },
         maxDuration: -1,
         maxInstanceLives: -1,
         maxUserLives: 50,
diff --git a/support/doc/api/openapi.yaml b/support/doc/api/openapi.yaml
index 70f2d97f5..5ce1f228a 100644
--- a/support/doc/api/openapi.yaml
+++ b/support/doc/api/openapi.yaml
@@ -2295,6 +2295,9 @@ paths:
                 permanentLive:
                   description: User can stream multiple times in a permanent live
                   type: boolean
+                latencyMode:
+                  description: User can select live latency mode if enabled by the instance
+                  $ref: '#/components/schemas/LiveVideoLatencyMode'
                 thumbnailfile:
                   description: Live video/replay thumbnail file
                   type: string
@@ -5291,6 +5294,14 @@ components:
       description: 'Admin flags for the user (None = `0`, Bypass video blocklist = `1`)'
       example: 1
 
+    LiveVideoLatencyMode:
+      type: integer
+      enum:
+        - 1
+        - 2
+        - 3
+      description: 'The live latency mode (Default = `1`, HIght latency = `2`, Small Latency = `3`)'
+
     VideoStateConstant:
       properties:
         id:
@@ -7482,6 +7493,9 @@ components:
         permanentLive:
           description: User can stream multiple times in a permanent live
           type: boolean
+        latencyMode:
+          description: User can select live latency mode if enabled by the instance
+          $ref: '#/components/schemas/LiveVideoLatencyMode'
 
     LiveVideoResponse:
       properties:
@@ -7497,8 +7511,9 @@ components:
         permanentLive:
           description: User can stream multiple times in a permanent live
           type: boolean
-
-
+        latencyMode:
+          description: User can select live latency mode if enabled by the instance
+          $ref: '#/components/schemas/LiveVideoLatencyMode'
 
   callbacks:
     searchIndex: