IntroductionHow to add CSS or JavaScript files to an Android/iOS projectHow to combat autoplay policiesPlayback issue with Internet Explorer 11Why does fullscreen not behave as expected on iOSWhy does the Network API not work on iOS devicesWhy doesn't Chromecast work when embedded in an iframe on iOSWhy can't I select another video quality on iOS/tvOS?Is YouTube supportedWhy does the player load only one audio track (even though there are several in the manifest)Is it possible to see 360 degrees photo with THEOplayerWhy the Visibility API does not work through an iframe on Safari and IE11What is an impressionHow to know whether a live stream is playingWhich error related events does the player exposeWhy did my subtitles stop workingHow does Media Engagement Index (MEI) affect Autoplay on ChromeWhat does the error message 'Unknown CDM error' meanWhat does the error message 'Something went wrong with Native playback' meanWhy are not all response headers exposedWhy does the currentTime seem off in my livestream & what can I do about itHow to remove CORS restrictions from a reproduction streamWhich network calls (or requests) does THEOplayer doWhy does the playback not work when using the Chrome iPhone/iPad simulatorWhat does the error message 'can only be initiated by a user gesture' imply? Can I still force the desired actionHow to remove unwanted CC track in iOS or SafariKnown Chromecast Limitations in 2.61.1Why do I get a gray play button in my Android WebView and how to remove it?MediaTek limitationsHow to use ProGuard with THEOplayer Android SDKSelf-hosting and versioning of THEOplayerDoes THEOplayer support EXT-X-DATERANGECan clipping be used on a playlistCan timeline thumbnails be made available before playback startWhat are the benefits of preloadingWhat are the player seeking and seeked events and when are they firedCan we use HLS or DASH adsHow to change text in THEOplayerChange text when AirplayingITP2.1 problems using THEOplayerRemoving context menu/'Powered by THEOplayer v2...'What aspects of THEOplayer do we need to take into account to deploy a proper Content Security Policy (CSP)How can we avoid that the player keeps looking for chunks/segments if they are not foundCan we show a custom message on 403 on mp4Can we prevent UpNext feature from redirectingIs it possible to preload VOD content while the pre-roll is playingWhy is my video not playing automaticallyIs it possible to have multiple player instances play at the same timeIs it a problem if the viewer pauses a live stream for longer than the DVR windowTHEOplayer Features & ModulesChromecast on my webplayer does not work any longer despite no change in my implementationHow to track network errorsWhat is the support for WowzaHow to use the CDN fallback/backup stream featureHow to apply accurate buffering strategyHow can I distribute 4K content?What is the collaboration between Azure Media Services and THEOplayerIs Portrait mode supportedHow to prevent screen recordingThe provided video source is incompatible with the license for this playerPage and Source domainsWhat does the error message “Something went wrong determining the initial period of the provided MPEG-DASH stream” meanWhy is my PlayReady stream not working in Chromium Edge?Which subtitle and CC formats are supported on native SafariHow to navigate through the documentation and resourcesHow to create a (great) ticketHow to investigate a ticketWhat are the limitations of AirPlayWhat are the Edgio challengesHow to use the Media Session APIHow to use THEOplayer iOS SDK on an M1 macWidevine CDM deprecation notice for old browser versions

How to apply accurate buffering strategy

By default, THEOplayer buffers 20 seconds of video including audio/subtitles in order to guarantee smooth playout. THEOplayer (alike other Web players) is relying on HTML SourceBuffer API for buffering purposes. Unfortunately there is no method which informs you how big the buffer size of given browser/device is. Of course, it can be different for device, and even browser. In consequence in edge circumstances might happen that the following error is encountered: Player error: Failed to execute 'appendBuffer' on 'SourceBuffer': The SourceBuffer is full, and cannot free space to append additional buffers.

Proactive strategy

One of the approach to deal with above issue is to apply proactive strategy which adjust player.abr.targetBuffer depending on what quality is currently used. The below table presents what approximately bandwidth is required for video streaming:

Resolutions Required Bandwidth (H264) Required Bandwidth (H265)
1280x720 (HD) 3Mbps 1.5Mbps
1920x1080 (FHD) 6Mbps 3Mbps
3840x2160 (UHD) 25Mbps 12Mbps
4096x2160 (4K) 32Mbps 15Mbps

Taking above table into account, the logic responsible for the proactive strategy can look like:

        player.addEventListener("representationchange", function (event) {
          // specifies how big bandwidth is required for the current quality
          var representationBandwidth = event.representation.bandwidth;
          // player.abr.targetBuffer is 20 by default
          var targetBuffer = player.abr.targetBuffer;

          // SD
          if (representationBandwidth < 3000000) {
            targetBuffer = 20;
          } else if (representationBandwidth > 3000000 && representationBandwidth < 6000000) {
            // HD
            targetBuffer = 10;
          } else if (representationBandwidth > 6000000) {
            //FHD, UHD, 4K
            targetBuffer = 5;

          player.abr.targetBuffer = targetBuffer;
          console.log('representationchange - updated player.abr.targetBuffer: ' + player.abr.targetBuffer);

Please note that the above numbers should be adjusted depending on the video content used.


Make sure to follow us on GitHub!
Copyright © 2022. All Rights Reserved.
New York