MP4 vs WEBM — which should I use?

Use MP4 (H.264) for maximum compatibility and YouTube uploads. Use WEBM (VP9) when you need smaller file sizes with similar quality, especially for web embedding.

How do I convert video format with FFmpeg?

Basic command: ffmpeg -i input.mp4 -c:v libx264 -crf 23 output.webm. This converts MP4 to WEBM while maintaining good quality.

Will converting video format reduce quality?

Quality depends on codec and bitrate, not file extension. Converting between same codecs with identical settings preserves quality. Lossy-to-lossy conversions always lose some quality.

Video Format Conversion Guide: MP4 vs WEBM vs MOV vs MKV

Format Comparison Table

Format	Best For	Quality	Compatibility
MP4 (H.264)	Web delivery, social media	Excellent	Universal ✓
WEBM (VP9)	Browser embedding, smaller files	Very Good	Modern browsers ✓
MOV (ProRes)	Editing masters, Apple ecosystem	Near-lossless	Apple/macOS ✓
MKV (H.265)	Archiving, high compression	Excellent	Select players ✓

Copy-Ready Conversion Commands

Convert to MP4 H.264 (Universal)

melt "input.mov" -consumer avformat:"output.mp4" vcodec=libx264 crf=23 acodec=aac

Convert to WEBM VP9 (Small file, web-ready)

melt "input.mp4" -consumer avformat:"output.webm" vcodec=libvpx-vp9 crf=30 acodec=vorbis

Convert to MOV ProRes (Editing master)

melt "input.mp4" -consumer avformat:"output.mov" vcodec=prores acodecpcm_s16le

When to Use Each Format

MP4/H.264: YouTube, TikTok, Instagram, Facebook — universal compatibility
WEBM/VP9: Website embeds where file size matters most
MOV/ProRes: Professional editing workflows on Mac
MKV/H.265: Archival storage with maximum compression

Need help picking a format? Use Bitrate Calculator for your target format, then use Trimpx convert preset to set the right parameters for your workflow.

Video Format Conversion: MP4 vs WEBM vs MOV vs MKV