MP4 Compressor

Need to compress MP4 video files? MP4 (MPEG-4 Part 14) is the most common video container on the web — universally supported by every modern browser, phone, tablet, smart TV, game console, and social platform. Despite this universality, MP4 files are often poorly encoded and dramatically oversized. Phone cameras default to high bitrates to preserve quality (an iPhone 13 Pro records 4K at up to 170 Mbps = 1.27 GB per minute); screen capture tools like OBS and Camtasia default to even higher bitrates to avoid frame drops; and video editors like Premiere and Final Cut default to conservative CRF values that prioritize quality over size. This MP4 compressor re-encodes to a tighter CRF without changing container or codec, producing smaller MP4 files that play identically but transfer faster, store easier, and upload without hitting size limits. Default output: H.264 CRF 28, AAC 128 kbps stereo, MP4 with +faststart for instant streaming.

• 1MP4 is universal but often poorly encoded at the source — re-compression with smart CRF yields 50-80% size reduction with no visible quality loss.
• 2Phone-recorded 4K MP4s hit 200 MB+ per minute, blowing past email attachments, Discord free-tier (25 MB), and even WhatsApp Status (16 MB). Compression is essential for sharing.
• 3The MP4 compressor runs locally — no uploading personal footage, family videos, and confidential business content to unknown third-party servers.
• 4Free, no account, no watermark, no daily limit — compress as many MP4s as you need. The tool runs FFmpeg compiled to WebAssembly entirely in your browser; there's no server cost to pass on.
• 5H.264 + AAC + MP4 is the only universally-supported combo across all modern devices and platforms. Re-encoding to this exact spec ensures your output plays everywhere.
• 6CRF (Constant Rate Factor) is the smart way to compress video — it allocates bits where they're visually needed (motion, detail) and saves bits where they're not (static backgrounds, darkness). The result is dramatically smaller files with perceived quality matching much larger sources.