VideoText workflow guide
To create an SRT file correctly, you need the exact block structure: subtitle number, start/end timestamps, subtitle text, then a blank line. This guide covers the manual method with a real format example, common validation mistakes (timing overlaps, bad timestamp separators, missing blank lines), and the faster AI workflow for long videos.
Upload the video or paste a public URL. Word-level timestamp alignment produces more accurate line breaks than sentence-level alignment — each subtitle break falls at a natural pause rather than a word boundary mid-phrase.
Flag any line above 17 CPS and split it. An 8-word subtitle in a 1.2-second window hits approximately 24 CPS — unreadable for most viewers. Merge subtitle lines shorter than 0.8 seconds, which display too briefly to register.
Subtitle overlap — where the next block starts before the previous one ends — causes display flicker in most players. Any gap shorter than 0.1 seconds between adjacent subtitles should be merged or widened to prevent rendering artifacts.
Export SRT for YouTube, Vimeo, and video editors. Export VTT for HTML5 web players and streaming platforms that support caption positioning. Choose burned-caption output for Instagram Reels, TikTok clips, and any social context where autoplay without sound is expected.
Each subtitle entry needs: sequence number, timestamp line, subtitle text, then one blank line before the next entry.
Use HH:MM:SS,mmm --> HH:MM:SS,mmm. Keep commas for milliseconds and use --> exactly.
Avoid very long lines. Split into natural phrases so captions stay readable on mobile screens.
Ensure each caption starts after the previous one ends and check that cue durations are long enough to read.
For full videos, auto-generate SRT first, then edit only mistakes instead of writing every timestamp manually.
Standard timed subtitle format: sequence number, timestamp pair (00:00:00,000 → 00:00:00,000 with comma separator), and one or two lines of caption text per block. Supported by YouTube, Vimeo, LinkedIn, most video editors, and accessibility workflows.
WebVTT format with period timestamp separators (00:00:00.000 → 00:00:00.000). Used by HTML5 video players, streaming services, and accessibility platforms. Unlike SRT, VTT supports <cue> positioning metadata, text styling, and karaoke-mode highlighting.
Permanently embedded caption text rendered directly into the video frame — cannot be toggled off by the viewer. Required for platforms that strip external caption tracks. Font rendering, shadow depth, and vertical position all need QA review after encoding because video compression can degrade caption legibility.
Generate SRT for YouTube upload, export burned captions for Instagram Reels, and produce VTT for course platform embeds — all from the same subtitle pass without reformatting timing.
Produce synchronized captions that meet WCAG 2.1 timing and reading-speed requirements. CPS validation catches lines that fail accessibility guidelines before the video goes live.
Export SRT or VTT for import into Premiere, DaVinci Resolve, or Final Cut Pro. Accurate word-level timestamps eliminate the need to manually re-sync caption timing after import.
Eight words spoken in 1.2 seconds: "we need to fix this before the deadline" at 24 CPS. The line must be split into two display segments within the same timing window to hit the readable 14–17 CPS range.
Block ending at 00:01:23,500 overlapping a block starting at 00:01:23,200 causes display flicker and rendering failure in most SRT players. A subtitle validator catches this before upload.
A two-line subtitle with 44+ characters per line at default font sizes clips at the bottom of mobile video frames. The safe area for mobile subtitles is a single line, 38 characters maximum, positioned at 85% vertical height.
Font stroke weight, drop shadow depth, and subtitle vertical position all shift slightly after H.264 encoding. Captions that look correct in preview may become harder to read in the encoded file — requires a post-encode QA pass before publishing.
UTF-8 encoding required. Maximum 1,500 subtitle blocks per file. Timestamp format: 00:00:00,000 (comma separator, not period). Files over 1,500 blocks need splitting before upload. YouTube auto-syncs uploaded SRT to audio — small timing offsets are corrected automatically.
TikTok generates its own auto-captions and displays them over uploaded SRT files in most cases. Burned captions are the reliable method for ensuring accurate captions appear on TikTok content. SRT upload works but TikTok may override it.
Instagram does not display soft subtitle tracks during autoplay in Feed or Reels. Burned captions are the only reliable method for ensuring captions appear for silent autoplay viewers. Instagram's built-in auto-caption feature can also be used after upload, but accuracy varies.
VTT uses period timestamp separators (00:00:00.000) while SRT uses commas (00:00:00,000). Swapping the separator character breaks parsing in most players. VTT files must begin with the WEBVTT header line — SRT files must not.
An SRT (SubRip Text) file is a plain text file that stores subtitles with timestamps. Each subtitle block has three parts: a sequential number, a timestamp line (start --> end), and the subtitle text. Example: 1 / 00:00:01,000 --> 00:00:03,000 / Hello world. SRT is the most widely supported subtitle format in the world.
Upload your video to VideoText (or paste a YouTube URL). The AI transcribes the audio and generates a precisely timed SRT file. Download the SRT and it's ready to use. This is far faster than writing timestamps manually.
Yes. Open a text editor (Notepad, TextEdit, VS Code). Write each subtitle block in this format: a number on line 1, timestamps on line 2 (00:00:01,000 --> 00:00:03,500), text on line 3, then a blank line. Save the file with .srt extension. Ensure encoding is UTF-8.
Use our free converters: VTT to SRT Converter or SBV to SRT Converter. Upload the file and download the converted SRT instantly.
In YouTube Studio, go to your video → Subtitles → Add Language → select the language → Upload file → select your SRT. YouTube will import the timestamps and text exactly as written.
Use this exact style: HH:MM:SS,mmm --> HH:MM:SS,mmm. Use commas for milliseconds, not periods. Example: 00:01:12,400 --> 00:01:15,200.
The most common mistakes are missing blank lines between subtitle blocks, overlapping timestamps, invalid arrows (using -> instead of -->), and wrong millisecond separators.
