Social Media Video Toolkit
Resize, crop, rotate, retime, mix audio, add text or a logo, generate captions, and compress a social-ready MP4.
Getting one video ready for Reels, TikTok, and Shorts usually means several separate editing passes - crop to 9:16, add captions, overlay a logo, compress for upload limits. This tool combines all of that into one FFmpeg pipeline running locally in your browser: resize and crop to a target aspect ratio, rotate, retime, mix in background audio, add text or a logo overlay, and compress the final MP4 in a single export. Automatic captions are the one step that isn't fully local - they call the same GPT-4o transcription service used by Speech to Text Transcription and cost 10 credits, since accurate speech recognition needs server-side processing.
Loading tool
How it works
- 01
Drop or select your source video.
- 02
Pick your target aspect ratio, crop, and rotation.
- 03
Add optional captions, text, logo overlay, and background audio.
- 04
Export the compressed, social-ready MP4.
Details
- Category
- Video
- Runs
- In your browser
- Files uploaded
- No
- Cost per run
- Free
- Sign-in
- Not required
- Works offline
- Yes, once loaded
Last updated 2026-08-03
Common questions
How are automatic captions timed?
The existing GPT-4o transcription service creates the text, then the browser distributes caption phrases evenly across the video. Edit the transcript before export when exact wording matters.
Does local processing upload the video?
FFmpeg editing is local. Only the optional automatic transcription sends the source to the existing authenticated transcription service and costs 10 credits.
What aspect ratios does it support?
Common social presets for vertical (9:16, Reels/TikTok/Shorts), square, and standard landscape, with crop and resize controls to hit each one.
Can I add my own logo or watermark?
Yes - overlay a text label or an image logo at a position and opacity you choose, alongside the other editing steps.