Free Online Video Processor

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Frequently Asked Questions

Everything you need to know about video format conversion and compression

MageKit supports conversion between MP4, MOV, WebM, and AVI formats. You can convert from any supported format to any other format with customizable quality and resolution settings.

Yes, MageKit Video Converter is completely free with no limitations. All video processing happens locally in your browser using WebAssembly (FFmpeg), so your videos never leave your device, ensuring maximum privacy and security.

The recommended maximum file size is 500MB per video. Larger files may work but could cause performance issues depending on your device's memory. Processing happens entirely in your browser, so available RAM is the main limiting factor.

You can choose from four quality presets: Original (CRF 18), High (CRF 23), Medium (CRF 28), and Low (CRF 33). Advanced users can also specify custom frame rates, maximum bitrates, buffer sizes, and additional FFmpeg parameters for fine-tuned control.

Video Format Comparison

MP4
MP4 (H.264/AVC)

  • ✅ Universal compatibility - works on all devices and platforms
  • ✅ Excellent balance of quality and file size
  • ✅ Widely supported by video players and editing software
  • ✅ Good for web streaming and social media
  • ⚠️ Larger file sizes compared to newer codecs

WebM
WebM (VP9)

  • ✅ Excellent compression efficiency - smaller files
  • ✅ Open-source and royalty-free
  • ✅ Optimized for web streaming
  • ✅ Good quality at lower bitrates
  • ⚠️ Limited support in Safari and iOS devices
  • ⚠️ Slower encoding/decoding compared to H.264

MOV
MOV (QuickTime)

  • ✅ Native format for Apple devices and Final Cut Pro
  • ✅ Supports high-quality video and audio
  • ✅ Excellent for video editing workflows
  • ⚠️ Larger file sizes
  • ⚠️ Less compatible with non-Apple platforms

AVI
AVI (Audio Video Interleave)

  • ✅ Simple container format with wide compatibility
  • ✅ Supported by most legacy systems
  • ⚠️ Very large file sizes - inefficient compression
  • ⚠️ Limited modern codec support
  • ⚠️ Not recommended for web or mobile use

💡 Expert Recommendation For general use, MP4 offers the best compatibility. For web streaming where file size matters, WebM provides better compression. MOV is ideal for Apple ecosystem and video editing workflows.

Quality & Compression Settings

Understanding CRF (Constant Rate Factor)

  • Lower CRF = Higher Quality (18 is nearly lossless)
  • Higher CRF = Smaller Files (33 is heavily compressed)
  • CRF 23 is the default - good balance for most use cases
  • Each +6 CRF roughly doubles compression (halves file size)

Quality Presets Explained

18

Original (CRF 18) - Near-lossless quality, slow encoding

23

High (CRF 23) - Excellent quality, moderate file size

28

Medium (CRF 28) - Good quality, smaller files

33

Low (CRF 33) - Acceptable quality, very small files

Advanced Settings Guide

Frame Rate Options

  • 24 fps - Cinema standard, smooth motion blur
  • 30 fps - Standard for web and mobile video
  • 60 fps - Smooth motion, gaming, sports
  • 120 fps - High-speed video, slow-motion source

Bitrate Control (maxrate & bufsize)

  • Maxrate: Caps peak bitrate to prevent quality spikes
  • Bufsize: Smooths bitrate variations over time
  • Useful for streaming or bandwidth-limited scenarios
  • Auto setting lets FFmpeg optimize based on content

Custom FFmpeg Parameters

  • For experienced users who need fine-grained control
  • Example: -tune film -profile:v high
  • ⚠️ Custom args may override other settings

Browser Compatibility

All major browsers support video format conversion through WebAssembly (FFmpeg.wasm). Processing performance depends on your device's CPU and available memory.

Chrome

Chrome/Edge: Best performance, full WebAssembly support

Firefox

Firefox: Full support, slightly slower encoding

Safari

Safari: Supported, but may have memory limitations

Performance & Limitations

Processing Speed Factors

  • CPU speed - faster processors = quicker encoding
  • Video resolution - 4K takes much longer than 1080p
  • Compression preset - 'slow' is higher quality but slower
  • Multiple formats - each format is processed separately

Optimization Tips

  • Use 'fast' or 'veryfast' presets for quicker encoding
  • Lower resolution first if file size is the priority
  • Process one video at a time for best performance
  • Close other browser tabs to free up memory