Watch a local video with subtitles

Choose a video before adding captions

1. Open Cast to Your TV and select your video.
2. Open the Subtitles menu after the video has been inspected.
3. Choose an available embedded track, or add a sidecar in SRT, WebVTT, ASS or SSA format.
4. Adjust subtitle text size if needed, then cast the selected file.

Preparation happens automatically after your selection. The same menu lets you switch a supported text track or turn subtitles off. Keep the subtitle file matched to the exact video edit: captions for a different cut can have correct formatting but incorrect timing.

Embedded text in MKV, MP4 and MOV

Supported embedded tracks are read from Matroska/WebM and MP4/MOV container records in bounded chunks. The whole video is not copied into memory just to extract a text track, and embedded text extraction has no general 256 MiB video-size cap. Converted caption text is capped at 5 MiB.

Some tracks use unsupported compression, encryption, unusual timing or fragmented MP4 layouts. The app can then leave embedded subtitles unavailable while the video remains playable. A separate SRT or WebVTT file is often the practical alternative. Do not assume a warning about optional subtitle metadata means the film’s video or audio tracks are damaged.

Choosing and checking a sidecar file

A sidecar is a separate caption file for the selected video. The app converts supported text locally into WebVTT, the timed-text format used by its player. Sidecars must be no larger than 5 MiB and contain valid timestamps and readable text. UTF-8 and UTF-16 text are supported.

If a file is rejected, check that it is actually an SRT, VTT, ASS or SSA file rather than an archive, web page or renamed document. An empty file and malformed cue times cannot produce useful captions. Save a corrected local copy and add it again. Caption selection follows the current video; selecting a different film does not build a reusable subtitle library.

Selectable text versus burn-in

Selectable ASS and SSA subtitles use simplified text. Their original placement, effects or typography may not survive conversion. Preserving styling uses burn-in where supported, drawing subtitles into newly prepared video frames with a bundled font; the original font appearance may still differ. Bitmap subtitles also require a supported burn-in path.

Burn-in is much more demanding than displaying a text track. It uses the whole-file conversion fallback with 256 MiB input and output limits. A multi-GB film that plays incrementally can therefore be too large for burn-in. For large films, a supported selectable text track is the more suitable choice. See large-video preparation for the distinction.

If captions do not appear on the TV

Check that the selected track is not Off and contains dialogue at the current playback position. Increase text size if captions are present but too small. If the source uses bitmap subtitles, selectable text alone cannot display them. Test with a short known-good SRT to distinguish a track problem from a connection problem.

Desktop and manual phone mirroring include captions in the rendered view; Android’s direct receiver renders supported text on the TV. Phone connection steps are covered in the Android and iPhone and iPad guides. Text remains local; account and playback verification are separate network services.