Help & FAQ
Get answers to common questions about using VidSpeed
Quick Navigation
Getting Started
How do I change video speed?
- Go to the Speed Changer page
- Click or drag & drop your video file into the upload area
- Adjust the speed slider (0.25x - 4x) or select a preset
- Configure audio and quality settings
- Click "Process Video" and wait for conversion
- Download your processed video
Can I process multiple videos at once?
Yes! VidSpeed supports batch processing:
- Click "Batch Processing" mode on the speed changer page
- Upload multiple video files (drag & drop or click to browse)
- All videos will use the same speed and settings
- Click "Process All" to start batch conversion
- Download each video individually or as a ZIP file
Is my video uploaded to a server?
No! VidSpeed processes everything in your browser using WebAssembly technology (FFmpeg.wasm). Your videos never leave your device, ensuring complete privacy and security. All processing happens locally on your computer or phone.
Troubleshooting Common Issues
❌ Processing Failed or Stuck
Possible Solutions:
- Refresh the page and try again
- Try a smaller video file first to test your browser's capability
- Close other browser tabs to free up memory
- Use a lower quality preset for faster processing
- Check if your video file is corrupted (try playing it in a video player)
- Try a different browser (Chrome and Edge work best)
⚠️ Memory Warning or Browser Crash
What's happening:
Large video files (>500MB or >1 hour duration) require significant browser memory. Your browser may slow down or crash if it runs out of memory.
Solutions:
- Close all unnecessary browser tabs and applications
- Use the "Low Quality" preset to reduce memory usage
- Try processing on a device with more RAM
- Split long videos into shorter segments before processing
- Ensure your device is plugged in (processing is intensive)
🔊 Audio is Distorted or "Chipmunk" Effect
When you speed up video, the audio pitch naturally increases (sounds like chipmunks). When you slow down video, the audio pitch decreases (sounds deep/slow).
Solution:
- Select "Adjust speed with pitch correction" in Audio Processing options
- This maintains natural audio pitch even when speed changes
- Note: Pitch correction adds slightly more processing time
⏱️ Processing is Taking Too Long
Expected Processing Times:
- Short video (<5 min, <100MB): 30 seconds - 2 minutes
- Medium video (5-20 min, 100-500MB): 2-10 minutes
- Long video (20-60 min, 500MB-1GB): 10-30 minutes
- Very long video (>1 hour, >1GB): 30+ minutes
Speed up processing:
- Use "Low Quality" or "Medium Quality" presets
- Disable pitch correction if you don't need it
- Use a modern desktop/laptop (mobile devices are slower)
- Process during off-peak hours when your device is less busy
📱 Not Working on Mobile/iOS
VidSpeed works on mobile browsers, but with limitations:
- iOS Safari: Works, but limited to smaller videos (<200MB recommended)
- Android Chrome: Works well for medium-sized videos
- Mobile Firefox: Works, but may be slower than Chrome
- Mobile devices have less memory and processing power
- For large videos, use a desktop/laptop computer for best results
Supported Video Formats
Input Formats (Upload)
VidSpeed accepts these video formats:
✅ Fully Supported
- MP4 (.mp4) - Most common, H.264/H.265
- MOV (.mov) - QuickTime, iPhone videos
- WebM (.webm) - Modern web format
- AVI (.avi) - Older Windows format
- MKV (.mkv) - Matroska container
⚠️ May Work (Untested)
- FLV (.flv) - Flash video
- WMV (.wmv) - Windows Media Video
- MPEG (.mpeg, .mpg) - MPEG-1/2
- 3GP (.3gp) - Mobile video
- OGV (.ogv) - Ogg video
Output Formats (Download)
Choose your output format:
📹 MP4 (H.264) - Recommended
Best for: Maximum compatibility, sharing on social media, viewing on any device
Pros: Works everywhere, good quality, reasonable file size
Cons: Slightly larger than WebM
🌐 WebM (VP9) - Smallest Size
Best for: Web uploads, YouTube, modern browsers
Pros: Excellent compression, smaller files, good quality
Cons: Not supported on older devices, slower encoding
🍎 MOV (QuickTime) - Apple Ecosystem
Best for: macOS, iOS, Final Cut Pro, iMovie
Pros: Native Apple format, works well in Apple ecosystem
Cons: May not play on some non-Apple devices
Performance Tips
🚀 Get Faster Processing
- Use Chrome or Edge: Best WebAssembly performance
- Close other tabs: Free up RAM for video processing
- Lower quality preset: Reduces encoding time significantly
- Disable pitch correction: If you don't need it, disable for 20-30% speedup
- Use desktop/laptop: Mobile devices are 3-5x slower
- Plug in your device: Processing at full performance requires power
💾 Reduce Memory Usage
- Process one video at a time: Even in batch mode, videos process sequentially
- Clear history regularly: Old processed videos stay in memory
- Use incognito mode: Starts with clean memory slate
- Restart browser: If processing multiple large files, restart between batches
- Lower resolution: If available in future, choose lower output resolution
⚡ Browser Requirements
Minimum Requirements:
- Modern browser with WebAssembly support (Chrome 57+, Firefox 52+, Safari 11+, Edge 16+)
- 4GB+ RAM recommended (2GB minimum)
- JavaScript enabled
- Stable internet for initial FFmpeg.wasm download (~30MB, cached afterward)
Recommended for Best Experience:
- Chrome or Edge browser (latest version)
- 8GB+ RAM
- Multi-core processor (4+ cores)
- Desktop or laptop computer
Feature Guide
📊 Processing History
VidSpeed automatically saves your processing history in your browser:
- View past conversions with thumbnails
- Search by filename
- Filter by date or speed setting
- Re-download previously processed videos (if still in cache)
- Clear individual entries or entire history
- Privacy: History stored locally, never sent to servers
⭐ Custom Presets
Save your favorite speed settings for quick access:
- Create presets with custom speed, audio, format settings
- Give each preset a memorable name (e.g., "YouTube Timelapse")
- Apply presets with one click
- Export/import presets to share with others or backup
- Presets sync across browser sessions (stored in IndexedDB)
🔗 Share Settings
Share your exact settings with others via URL:
- Click "Share" to generate a URL with your current settings
- Settings encoded in URL parameters (speed, audio options, format, etc.)
- Anyone with the URL can use your exact settings
- Useful for tutorials, teams, or documenting workflows
- Note: URLs don't include video files, only settings
Related tool: If you need to convert other media formats, check out VideoConvert.io for comprehensive video conversion capabilities.
Still Need Help?
Check out our detailed guides and use case examples