UD5 Toolkit
Subtitle File Converter - Online SRT ↔ VTT & Timestamp Shift
Convert subtitle files between SRT and WebVTT formats. Also shift all timestamps forward/backward. Works locally.
Video Subtitle Burner - Online Hardcode SRT into Video
Choose Video File
MP4, WebM, MOV, AVIChoose SRT File
.srt subtitle fileFrequently Asked Questions
Hardcoding (or burning) subtitles permanently embeds them into the video stream. Unlike soft subtitles (separate track), hardcoded subs cannot be turned off and are visible on any player or device.
Our tool runs entirely in your browser – no upload to servers, no installation. It's fast, private, and works on any modern device (Windows, Mac, iOS, Android).
Currently we support SRT (SubRip) files. Make sure your file uses standard timecodes like
00:00:10,500 --> 00:00:15,000.Yes! Use the style panel to change font family, size, text color, background color with opacity, and vertical position (top/middle/bottom with custom margins).
It depends on video length and your device's performance. The tool renders each frame with subtitles in real-time. A 1‑minute HD video may take 1–3 minutes. Shorter videos are faster.
No – everything stays on your device. Processing uses your browser's engine (WebCodecs/Canvas + MediaRecorder). No data is sent to external servers.
WebVTT to SRT Converter - Online Subtitle Format Swap
Convert WebVTT subtitle files to SRT and vice versa. Handles formatting conversion and encoding. No upload, pure client-side parsing.
SRT to WebVTT Converter - Online Subtitle Format Changer
Convert .srt subtitles to .vtt format for web video players. Preserves all timestamps and formatting. Local.
SRT Subtitle Creator - Online Add Timestamps
Create .srt subtitle files manually by adding lines and setting times with a simple player. Download the result. Local.
Online SRT Subtitle Shifter - Adjust Timing & Sync
Load an SRT file and shift all timestamps forward or backward by milliseconds or seconds. Fix out-of-sync subtitles instantly. Download corrected file.
Video Audio Merger/Separator - Online Replace or Remove Soundtrack
Remove the original audio from a video and attach a new soundtrack. Or extract audio. All processed locally.
Online Video Trimmer - Cut & Save Clips Locally
Set start and end times for a video and trim it without re-encoding. Download the clip. Pure browser.
ASCII Video Player - Online Convert Webcam to Text Art Live
Turn your webcam feed into real‑time ASCII art. Adjust density and character set. Fun for streams and demos. No upload.
Base32 Encoder & Decoder - Online Base32 Converter
Encode or decode text using Base32 scheme. Ideal for legacy systems and data obfuscation. Works completely offline in your browser for maximum security.
Image Compression Visualizer - Online Before/After Slider
Drag a slider to compare your original image with a compressed version (e.g., WebP). See the quality difference and file size savings.
Convolution Reverb Demo - Online Impulse Response Player
Apply realistic reverbs (cathedral, hall, room) to any audio using pre‑loaded impulse responses. Hear the difference instantly.
Base64 Encoder & Decoder - Online Base64 Converter
Convert text and files to Base64 or decode Base64 back to original content. Processed locally with no server upload, ensuring complete data security.
GIF Playback Speed Changer - Online Slow Down or Speed Up
Load an animated GIF and adjust its frame delay to make it slower or faster. Download the modified GIF. All local.
Online Video Reverser - Play & Save Backwards
Reverse any short video clip and download the backward version. Fun for creative effects. Browser‑based.
Picture‑in‑Picture Tester - Online Float Video Anywhere
Open a test video in Picture‑in‑Picture mode. Control entering and leaving PiP. Copy the code snippet for your own app.
Adaptive Bitrate Streaming Simulator - Online HLS/DASH Demo
Simulate adaptive bitrate logic by switching between different quality video segments. See how ABR algorithms work.
Audio to GIF Waveform - Online Animated Sound Visualizer
Upload an audio clip and generate an animated GIF of its waveform dancing. Shareable sound snippet. Canvas magic.
ROT13 Encoder & Decoder - Online Caesar Cipher ROT13
Easily apply ROT13 cipher to obfuscate or reveal text. A classic letter substitution cipher that works bidirectionally. Purely client-side processing.
Reduced Motion Demo - Online Prefers‑Reduced‑Motion Switcher
Toggle between full and reduced motion on a live animated page. See how to design for vestibular disorders. Educational.
Unicode Bold/Serif/Script Converter - Online Text Transformer
Convert normal text to Unicode mathematical bold, italic, script, fraktur, and double‑struck. Copy rich text for anywhere.
QR Code vCard Maker - Online Contact Card Code
Create a QR code that contains your full vCard contact information. Scan to save directly to a phone. No data leaves browser.
SVG Transform Merger - Online Combine Transforms
Take an SVG element with multiple transform attributes and merge them into a single matrix. Simplify your SVG code locally.
Compression Streams API Demo - Online Gzip/Deflate Raw
Compress and decompress text using the browser's native Compression Streams API. See the binary output size.
Real‑Sample Contrast Checker - Online See Paragraph
See how a full paragraph looks with your chosen text and background colors. Not just a ratio; the real appearance.
WASM Audio Decoder - Online Play FLAC/Opus Locally
Decode FLAC, Opus, or OGG audio files in the browser using compiled WASM libraries. Play instantly without server uploads. Keep audio private.
Setlist Builder – Online Drag Songs into Order & Time
Drag songs into a setlist and see total duration. Perfect for planning a concert or DJ set.
Text to Ordered List - Online Automatic Numbering HTML
Paste lines of text and automatically convert to an HTML ordered list with correct numbering and indentation.
Brotli Compression Level Tester - Online Optimal Setting
Compress text with Brotli at different quality levels. See size reduction and time. Find the sweet spot for your static assets.
prefers‑reduced‑motion Tester - Online A11y Check
Simulate reduced motion preference and test your animations. Copy the media query snippet. Keep your users safe.
UI Animation Timing Demo - Online Easing Presets
Compare all CSS easing presets side by side on a bouncing ball. See which curve fits your UI animation.