Version: 2.67.0

How to insert subtitles?

You may be asking this question if you need captions or subtitles on your video. The sourceDescription property textTracks can be used to add an array of side-loaded text tracks to the player. All valid tracks will be available for playback as long as the player’s source is not set again. In the following guide you will find several related topics and some code samples for different SDKs.

The textTracks property and objects can also be used for other purposes, e.g.: for including preview thumbnails and chapters. Please see linked documentation and article to find out more.


Web SDKAndroid SDKiOS SDKtvOSAndroid TV SDKChromecast SDK

Related questions

  • Can I activate captions in THEOplayer? How?
  • Can I load subtitles in several languages, for the user to choose?
  • Can I add styles to my subtitles


The feature texttrackrendering must be active on your license.

Code examples


Each text track should be described as a TextTrackDescription.

player.source = {
sources: [
src: "//path/to/your-manifest.m3u8", // sets source
type: "application/x-mpegurl" // sets type - find other values at
textTracks: [
default: true, //optional
kind: "subtitles", //optional - find other values at
label: "English subs", //optional - this will appear in your UI
src: "path/to/your-subs-track1.vtt",
srclang: "en"

Android SDK

public static final SourceDescription SOURCE_WITH_SUBS =
.textTracks(new TextTrackDescription(
"path/to/your-subs-track1.vtt", //src
true, //isDefault
"en", //srclang
"en" // label


var sampleSource: SourceDescription {
let src = "https://your.m3u8"
let stream = "application/x-mpegurl"
let textTrack1 = TextTrackDescription(src: "https://your.webvtt", srclang: "English", isDefault: true, kind: .subtitles, label:"English")
let textTrack2 = TextTrackDescription(src: "https://your.webvtt", srclang: "Arabic", isDefault: false, kind: .subtitles, label:"Arabic")
return SourceDescription(
source: TypedSource(
src: src,
type: stream
textTracks: [textTrack1,textTrack2]

Then set the source to the player by:

self.theoplayer.source = sampleSource

Subtitle styling

To style your subtitles look into the player source property "textTrackStyle". Documentation: