YouTube subtitle file formats and UTF-8 text
A caption file needs the actual words and the times at which they appear. Choose a supported format that preserves the information you need. Basic SRT or SBV files are useful for straightforward text, while an advanced format's name does not guarantee every styling feature survives import.
Choose a maintainable format
| Format | YouTube's stated support | Practical implication |
|---|---|---|
| SubRip .srt | Basic versions; plain UTF-8; styling markup not recognised | Use timed text and review the imported appearance |
| SubViewer .sbv or .sub | Basic versions; plain UTF-8; styling markup not recognised | Its timestamp syntax differs from SRT |
| WebVTT .vtt | Positioning supported; styling limited | Do not assume a browser CSS class transfers into YouTube |
| TTML .ttml | Partial implementation; styling and positioning supported within its implementation | Check the actual imported features |
An original SRT timing example
1 00:00:00,000 --> 00:00:02,400 This box contains the main item. 2 00:00:02,400 --> 00:00:05,200 The cable is supplied separately.
The wording and times above are an invented formatting example, not captions for an existing video. Replace them with the actual speech and relevant sound information, then synchronise the file with the final video version.
Review text and timing together
Use the final edit
Changes to an introduction or cut can move every later cue. Keep a clear video version reference with the caption file.
Preserve the actual words
Check names, product versions and meaningful conditions against the audio. Add relevant non-speech information where needed for understanding.
Inspect the import
Play back the resulting captions in the actual destination. Verify characters, timing and any supported positioning rather than relying only on the source file's appearance.
Check reading at normal speed
Use the line checker as a chosen length aid, then watch the real scene. A character count cannot decide whether a cue is readable in its available time.
Before handing off the file
- The selected extension matches the actual syntax.
- Required plain-text encoding is preserved.
- Cue times match the final edit.
- Caption text retains conditions that change the meaning.
- The imported version has been reviewed at normal playback speed.