Adding subtitles to a video used to mean transcribing audio by hand, lining up timestamps one line at a time, and exporting through a clunky editor. Today you can generate accurate, properly timed captions automatically, edit them in minutes, and export them in whatever format your platform expects. This guide covers the whole process: subtitle types, what SRT and VTT files actually contain, how to build caption files with AI or by hand, the formatting rules players expect, and how to upload closed captions to YouTube, Instagram, and LinkedIn. ## Subtitles vs. Closed Captions vs. Open Captions These terms get used interchangeably, but they mean different things, and the difference affects which format you export. - **Subtitles** assume the viewer can hear the audio and just need the dialogue in text. Traditionally they cover spoken words only, and are often used for translation. - **Closed captions (CC)** are designed for accessibility. They include dialogue plus non-speech information — `[music playing]`, `[door slams]`, speaker labels — and viewers can toggle them on or off. They live in a separate file the player loads alongside the video. - **Open captions** (also called burned-in or hardcoded captions) are baked directly into the video frames. They are always visible and cannot be turned off. In everyday use, "subtitles" and "captions" overlap heavily. The practical decision is whether your text is a **separate sidecar file** the viewer can toggle or **burned into the video** permanently. More on that below. ## Why Subtitles Matter Captions are not a nice-to-have anymore. They affect how many people watch your video and how far it travels. - **Accessibility**: Roughly 1 in 5 people have some degree of hearing loss. Captions make your content usable for them, and in many regions captioning public video content is a legal requirement. - **Silent autoplay**: The majority of social video is watched with the sound off. On a muted feed, captions are the only thing carrying your message. - **SEO and discovery**: Search engines and platform algorithms read caption text, so a caption track gives them more to index. - **Comprehension**: Captions help viewers follow accents, technical terms, fast speech, and noisy audio. - **Searchability**: Text is searchable; audio is not. A caption file is a written record you can search, quote, and repurpose into show notes, posts, or clips. - **Reach**: With translated subtitles, a single video can serve audiences in multiple languages. ## Subtitle File Formats Explained Two formats cover almost every situation. ### What is an SRT file? An SRT file (SubRip Text) is a plain text file with a `.srt` extension containing numbered subtitle entries. Every entry has four parts: 1. A sequence number 2. A timestamp range (`start --> end`) 3. The subtitle text, on one or two lines 4. A blank line separating it from the next entry ``` 1 00:00:01,000 --> 00:00:04,500 Welcome to today's presentation on audio transcription. 2 00:00:05,000 --> 00:00:08,200 I'm going to cover three main topics. ``` That is the entire format: no styling, no positioning, no metadata, which is exactly why it works everywhere. YouTube, Vimeo, Facebook, LinkedIn, and virtually every video editor and player supports SRT. If you only learn one format, learn this one. ### What is a VTT file? VTT (Web Video Text Tracks) is the web standard, required for HTML5 video using the `` element. It looks like SRT but starts with a `WEBVTT` header, supports CSS styling and positioning, and uses a period rather than a comma in its timestamps. Use it for video embedded on your own site or app. ### SRT vs. VTT | Feature | SRT | VTT | |---------|-----|-----| | File extension | .srt | .vtt | | Encoding | Plain text | Plain text with header | | Styling | None | CSS styling supported | | Positioning | None | Position and alignment | | Browser support | Via video players | Native HTML5 | | Platform support | Universal | Web-focused | For most workflows, export **SRT for platform uploads and VTT for websites**. They carry the same content, and a good [subtitle generator](/features/subtitle-generation) produces both from the same transcription, so you do not have to choose up front. ## Subtitle Formatting Rules These are not style preferences. Players, platforms, and human eyes are all built around them. - **Maximum 2 lines per subtitle.** More than two obscures too much of the video. - **Maximum 42 characters per line.** Keeps captions readable on small screens. - **Minimum display time of 1 second.** Anything shorter flashes past before it can be read. - **Maximum display time of 7 seconds.** Longer captions feel stuck on screen. - **Timestamps use commas** for milliseconds in SRT (`00:01:23,456`), not periods. VTT uses periods. - **Save as UTF-8** so accented characters and non-Latin scripts survive the round trip. - **Break lines at natural phrase boundaries**, and use proper capitalization and punctuation. ## How to Generate Subtitles: Two Methods ### Method 1: AI generation (fastest) Upload your media to a transcription tool that supports subtitle export, and the caption file comes back timed and ready. 1. **Upload your video or audio.** Any common format works — MP4, MOV, WEBM, MP3, WAV. You can also paste a URL from a hosting platform if your tool supports it. 2. **Let the AI transcribe.** The audio is cleaned, normalized, and segmented, a speech model converts it to text, and the result comes back with punctuation, speaker labels, and a timestamp on every line. Because the text is aligned to the audio, captions sync to speech automatically. Accuracy exceeds 98% on clear audio. 3. **Edit the text and timing.** Fix any misheard words and nudge timestamps where needed. 4. **Style the captions.** Choose font, size, color, and background if you plan to burn them in. 5. **Export.** Download a sidecar **SRT or VTT** file, or **burn the captions into the video** and export a finished MP4. Blazescribe also exports TXT, DOCX, and PDF, so the same transcription doubles as a written transcript. An hour of content is typically ready in 2–3 minutes, and turnaround stays flat as your volume grows. The fastest way to try it is with a [free subtitle generator](/free-subtitle-generator): upload a clip and check the timing yourself. ### Method 2: Manual creation You can write an SRT file in any text editor — Notepad, TextEdit, VS Code. Complete control, no cost, and very slow. 1. Open a text editor and create a new file. 2. Type the sequence number, starting at 1. 3. Add the timestamp range in `HH:MM:SS,mmm --> HH:MM:SS,mmm` format. 4. Type the subtitle text: two lines maximum, 42 characters per line. 5. Add a blank line, then repeat for the next entry. 6. Save with a `.srt` extension, using UTF-8 encoding. Budget 5–10 minutes per minute of video. A 10-minute video is 1–2 hours of work, plus a pass to check every timestamp against the audio. Manual creation makes sense for fixing a handful of lines, not for captioning a whole video from scratch. ### Which method should you use? Generate with AI, then edit by hand. When you are comparing tools, the factors that matter are accuracy on your kind of audio, how many hours of video you produce a month, whether you need more than one language, whether it exports the formats your platforms expect, and whether it meets your security and compliance requirements. ## Editing Timing and Fixing Errors AI transcription is accurate but not flawless, and a quick review makes a big difference. - **Proofread proper nouns and jargon.** Names, brands, abbreviations, and technical terms are where errors cluster. Read these first. - **Check the numbers.** Dates, prices, statistics, and measurements are worth verifying against the audio. - **Adjust timing where it drifts.** A caption should appear as the speaker starts a line and clear as they finish. It should not run past a scene change. - **Split long lines.** Break captions at natural pauses, inside the two-line, 42-character limit. - **Remove filler.** You do not need every "um" and "uh." Trimming them makes captions easier to read. A dedicated [subtitle editor](/subtitle-editor) lets you make these changes against the video timeline, so you can see and hear exactly where each line lands. ## Common Caption Problems and Fixes - **Captions out of sync.** Check the timestamps against the audio. If every line is uniformly early or late, shift them all by the same offset rather than fixing them one by one. - **Garbled characters.** Save the file as UTF-8. Accented characters and non-Latin scripts break under other encodings. - **Text overflowing the frame.** Keep lines under 42 characters and use no more than two lines per entry. - **Captions not appearing at all.** Every entry needs its sequential number and a blank line before the next. Some players fail silently without them. ## Styling Captions for Social Short-form video on TikTok, Reels, and Shorts has its own caption style: bold, high-contrast, and usually a word or short phrase at a time, centered and animated. - **Use a heavy sans-serif font** so text reads at a glance on a small screen. - **Add a solid or semi-transparent background**, or a thick outline, so captions stay legible over any footage. - **Keep lines very short.** These platforms favor punchy, one-line captions over full sentences. - **Position captions in the safe zone**, clear of the platform's UI overlays at the top and bottom of the frame. For social, captions are almost always burned in: the platforms display open captions inline and viewers expect them styled. ## Burned-In vs. Sidecar Files: Which to Use This is the core decision once your captions are ready. **Burn subtitles into the video (open captions) when:** - You are posting to TikTok, Reels, or Shorts, where styled captions are the norm. - You want guaranteed visibility regardless of the player or the viewer's settings. - You are repurposing clips across platforms and want one self-contained file. **Use a separate sidecar file (closed captions) when:** - You are uploading to YouTube, Vimeo, or a website where the player handles captions. - You want viewers to toggle captions on or off. - You need multiple language tracks on the same video. - You may revise the text later without re-rendering the whole video. When you need permanent captions, [burn subtitles into video](/features/burn-subtitles-into-video) directly from your transcription, so the styling and timing carry straight through to the exported MP4. ## Adding Subtitles in Other Languages Generate the subtitles in the original language, then translate the caption track. Because the timing is already aligned to the audio, a translated track keeps the same timestamps: you swap the text, not re-sync from scratch. Blazescribe transcribes audio in 50 languages and translates a finished transcript into 106, so your source language and your target markets do not have to be the same short list. Export one sidecar file per language and let viewers pick, or burn a single language in for a specific market. ## How to Add Closed Captions to YouTube YouTube auto-generates captions, but they are often inaccurate, especially with technical content, accents, or multiple speakers. Auto-captions land around 70–85% accuracy; a reviewed caption file reaches 98%+. That gap is worth closing: - YouTube indexes caption text, so accurate captions give the algorithm accurate signals. - Videos with captions see 40% higher watch time on average. - 466 million people worldwide have disabling hearing loss. ### Step 1: Generate the caption file Use the original video file if you still have it, or download it from YouTube Studio. Upload it, let the AI produce a timestamped transcript, and export **SRT** (or VTT). ### Step 2: Review and edit Run the review pass above: proper nouns, technical terms, numbers, line length, and timing. Captions should appear the moment the speaker starts and clear when they stop. ### Step 3: Upload to YouTube Studio 1. Open **YouTube Studio** and select your video. 2. Click **Subtitles** in the left sidebar. 3. Click **Add Language** and choose your language. 4. Click **Add** next to Subtitles. 5. Select **Upload file** and choose your SRT. 6. Review the preview and click **Publish**. ### YouTube caption best practices Every formatting and timing rule above applies here: two lines per caption frame, 42 characters per line, 1 to 7 seconds on screen, and no caption running past a scene change. Captions add two rules of their own. Put non-speech audio in brackets — `[applause]`, `[music]` — and identify speakers when more than one person talks ("HOST:", "GUEST:"). And do not censor: captions should match what was actually said. ### Multiple languages on one video 1. Generate captions in the video's language. 2. Translate the track into your target languages. 3. Upload each language as a separate subtitle track in YouTube Studio. 4. Viewers choose their preferred language from the CC menu. ### A note on community contributions YouTube used to let viewers submit captions for other people's videos, but that feature was disabled. Uploading your own file is now the only way to guarantee accurate captions on your channel. ## Where Else to Use Subtitle Files - **Vimeo**: upload the SRT under video settings → Distribution → Subtitles. - **Instagram (Reels and feed video)**: Instagram shows auto-captions, but burn captions in before uploading if you want control over styling and accuracy. Styled open captions are standard for Reels and perform well on a muted feed. - **LinkedIn**: upload an **SRT** in the post composer when you publish native video. LinkedIn video plays silently in-feed, so captions noticeably improve watch time. - **Video editors**: import the SRT as a subtitle track in Premiere, Final Cut, or DaVinci Resolve. - **LMS platforms**: most learning management systems accept SRT for course videos. - **Your own site**: serve a VTT file to the HTML5 `` element. Whatever the platform, the toolchain is the same: transcribe, edit, style, and export in the format each one needs. ## FAQ ### What is an SRT file? A plain text file with a `.srt` extension that holds numbered subtitle entries, each with a timestamp range and one or two lines of text. It carries no styling or positioning, which is why nearly every platform, player, and editor accepts it. ### SRT vs. VTT — which should I use? Use **SRT** for uploads to YouTube, Facebook, LinkedIn, and most editors. Use **VTT** for HTML5 video on your own website, or when you need styling and positioning. When in doubt, export both; they carry the same content. ### Can I create an SRT file by hand? Yes, in any text editor. Expect 5–10 minutes of work per minute of video, plus a timing pass. Generating a draft with AI and correcting it lands in the same place, much faster. ### Are YouTube's auto-captions good enough? Usually not. They sit around 70–85% accuracy and struggle with jargon, accents, and overlapping speakers. Uploading your own reviewed SRT gets you to 98%+ and gives YouTube clean text to index. ### Do subtitles help SEO? Yes. Caption text is machine-readable, giving search engines and platform algorithms more context to index, on top of the engagement boost captions bring. ### How do I add subtitles permanently? Burn them into the video (open captions). This bakes the text into the frames so it is always visible and survives re-uploads across platforms — ideal for social clips. ### Can I add subtitles in multiple languages? Yes. Generate captions in the source language, translate the track, and export one sidecar file per language so viewers can choose — or burn a specific language in for a target market. --- Captions make your videos more accessible, more watchable, and easier to find. Generate properly timed subtitles in minutes, edit them on the timeline, and export SRT, VTT, or a burned-in MP4. [Sign up for Blazescribe](/signup) and caption your next video.