Back to Blog

Common Media Conversion Mistakes and How to Avoid Them

January 30, 2025
9 min read
By Expi Team

Common Media Conversion Mistakes and How to Avoid Them


Media conversion seems straightforward—just change the format, right? Unfortunately, many people make mistakes that result in poor quality, compatibility issues, or wasted time. This guide covers the most common pitfalls and how to avoid them.


Mistake 1: Converting Already Compressed Files Multiple Times


The Problem

Each time you convert a compressed video (like MP4, AVI, or MOV), you're re-encoding it, which causes quality loss. Converting the same file multiple times compounds this loss.


Example:

  • Original: High-quality source file
  • First conversion: Small quality loss
  • Second conversion: More quality loss
  • Third conversion: Significant degradation

The Solution

  • Always work from the original source file when possible
  • If you must convert multiple times, use lossless or near-lossless formats for intermediate steps
  • Keep your original files until you're certain the conversion is correct

Best Practice

Create a workflow that minimizes conversions:

1. Start with the highest quality source

2. Convert directly to your final format

3. Only re-convert if absolutely necessary


Mistake 2: Using Wrong Resolution or Aspect Ratio


The Problem

Converting to the wrong resolution or aspect ratio can result in:

  • Distorted images (stretched or squashed)
  • Black bars (letterboxing or pillarboxing)
  • Unnecessary file size increases
  • Poor viewing experience

Common Scenarios


Stretching 4:3 to 16:9:

  • Original: 640x480 (4:3 aspect ratio)
  • Wrong: Force to 1920x1080 (16:9) → Stretched, distorted
  • Right: Maintain 4:3 or crop/letterbox appropriately

Upscaling Low Resolution:

  • Original: 480p video
  • Wrong: Convert to 4K → No quality gain, huge file size
  • Right: Keep original resolution or upscale with proper algorithms

The Solution

  • Check your source file properties before converting
  • Match aspect ratio or crop intentionally
  • Only upscale if you have a good reason (and use proper upscaling tools)
  • Use Expi's preview feature to check results before converting

Mistake 3: Ignoring Audio Settings


The Problem

Many people focus only on video quality and forget about audio, leading to:

  • Poor audio quality
  • Audio/video sync issues
  • Missing audio tracks
  • Incompatible audio codecs

Common Issues


Low Audio Bitrate:

  • Default settings might use 128 kbps
  • For music or high-quality content, this is too low
  • Result: Compressed, tinny audio

Wrong Audio Codec:

  • Some devices don't support certain audio codecs
  • AAC is widely compatible, but AC3 might not work everywhere
  • Result: No audio playback on some devices

Audio Sync Problems:

  • Converting frame rate without adjusting audio
  • Using wrong sample rates
  • Result: Audio and video out of sync

The Solution

  • Set appropriate audio bitrate: 192-256 kbps for most content, 320 kbps for music
  • Use compatible codecs: AAC for maximum compatibility
  • Match sample rates: Keep original or use 44.1 kHz / 48 kHz
  • Test audio after conversion, especially for longer videos

Mistake 4: Choosing Wrong Output Format


The Problem

Not all formats are created equal. Choosing the wrong format can cause:

  • Compatibility issues
  • Unnecessary file size
  • Missing features
  • Playback problems

Format Selection Guide


For Web/Streaming:

  • ✅ MP4 (H.264) - Best compatibility
  • ❌ AVI - Large files, limited web support
  • ❌ MKV - Not universally supported in browsers

For Editing:

  • ✅ MOV (ProRes) - Professional editing
  • ✅ MP4 (High quality) - Standard editing
  • ❌ Highly compressed formats - Difficult to edit

For Archival:

  • ✅ MP4 (H.264) - Maximum compatibility
  • ✅ MKV (H.265) - Modern, efficient
  • ❌ Proprietary formats - May not be readable in future

For Mobile Devices:

  • ✅ MP4 (H.264) - Universal support
  • ❌ Some newer codecs - May not work on older devices

The Solution

  • Know your target platform before converting
  • Test on target device if possible
  • Use widely compatible formats unless you have specific requirements
  • Check device specifications for supported formats

Mistake 5: Using Default Settings Without Understanding


The Problem

Default conversion settings are often "safe" but not optimal:

  • May produce larger files than necessary
  • May not use best quality settings
  • May not match your specific needs

Common Default Issues


Bitrate Too High:

  • Default might be 10 Mbps for 1080p
  • For web, 5-8 Mbps might be sufficient
  • Result: Unnecessarily large files

Bitrate Too Low:

  • Default might be optimized for file size
  • For archival, this loses quality
  • Result: Poor quality output

Wrong Preset:

  • Default might use "fast" preset
  • For final output, "slow" or "medium" is better
  • Result: Lower quality or larger files

The Solution

  • Understand your settings before converting
  • Test different settings on a sample file
  • Use presets that match your use case
  • Adjust based on results - don't just accept defaults

Mistake 6: Not Checking Output Before Batch Processing


The Problem

Batch processing hundreds of files with wrong settings wastes:

  • Time (re-converting everything)
  • Storage space (wrong format files)
  • Processing resources

The Solution

  • Always test on one file first
  • Check the output - quality, size, compatibility
  • Verify settings before processing the batch
  • Keep originals until you confirm the conversion is correct

Mistake 7: Converting to Lower Quality Unnecessarily


The Problem

Some people convert high-quality sources to lower quality "to save space," but:

  • You can't get quality back later
  • Storage is cheap
  • You might need quality later

When Lower Quality Makes Sense

  • ✅ Final distribution format (web, social media)
  • ✅ Creating previews or thumbnails
  • ✅ Storage constraints (but keep originals)

When to Keep High Quality

  • ✅ Source files (always keep originals)
  • ✅ Archival copies
  • ✅ Files you might edit later
  • ✅ Professional work

The Solution

  • Keep originals in highest quality
  • Create distribution copies at appropriate quality
  • Don't delete originals after conversion
  • Use quality settings that match your needs

Mistake 8: Ignoring Metadata


The Problem

Metadata (title, description, creation date, etc.) can be lost during conversion, causing:

  • Loss of important information
  • Difficulty organizing files
  • Missing copyright information

The Solution

  • Preserve metadata when possible
  • Add metadata if your tool supports it
  • Use consistent naming to compensate for lost metadata
  • Document important files separately if needed

Mistake 9: Not Using Hardware Acceleration


The Problem

Software encoding is much slower than hardware acceleration:

  • 10x slower on some systems
  • Wastes time on batch conversions
  • Uses more CPU resources

The Solution

  • Enable hardware acceleration if available
  • Check your system supports it (NVIDIA, AMD, Intel, Apple Silicon)
  • Use appropriate codecs for hardware acceleration (H.264/H.265)
  • Test performance - hardware acceleration should be significantly faster

Mistake 10: Rushing the Conversion Process


The Problem

Rushing leads to:

  • Wrong settings
  • Skipped quality checks
  • Batch processing errors
  • Wasted time fixing mistakes

The Solution

  • Take time to configure settings correctly
  • Preview before converting when possible
  • Test on samples before batch processing
  • Double-check output format and quality
  • Be patient - good conversions take time

Best Practices Summary


1. Always work from original source files

2. Test settings on one file before batch processing

3. Check aspect ratios and resolutions

4. Don't ignore audio settings

5. Choose formats based on your target platform

6. Understand and adjust default settings

7. Preserve metadata when possible

8. Use hardware acceleration

9. Keep original files until conversion is verified

10. Take time to do it right the first time


Tools to Help Avoid Mistakes


Expi's Features:

  • Preview before converting
  • Preset configurations for common use cases
  • Visual feedback on settings
  • Batch processing with consistent settings
  • Hardware acceleration support

General Tips:

  • Use tools with preview capabilities
  • Test on target devices when possible
  • Keep organized file structures
  • Document your conversion settings
  • Learn from mistakes (keep notes)

Conclusion


Media conversion mistakes are common but avoidable. The key is understanding your source files, your target requirements, and your conversion settings. Take time to configure correctly, test before batch processing, and always keep your originals.


Remember: It's better to spend a few extra minutes getting settings right than hours re-converting files or dealing with compatibility issues. Quality and compatibility should always come before speed.