CFR vs VFR: Constant vs Variable Frame Rate Explained
Published on April 16, 2026
CFR (Constant Frame Rate) delivers frames at a fixed interval, like exactly 30 frames every second. VFR (Variable Frame Rate) adjusts the frame rate on the fly, sending more frames during fast action and fewer during static scenes. Most professional video workflows use CFR, while phones, screen recorders, and webcams often produce VFR output.
How CFR Works
With CFR, every second of video contains the exact same number of frames. A 30fps CFR video has frames spaced exactly 33.33 milliseconds apart, no exceptions. This predictability makes CFR easy for editing software, streaming platforms, and media players to handle. Every major video codec and container format supports CFR without issues.
How VFR Works
VFR assigns timestamps to each frame independently. If nothing changes on screen, the encoder might drop to 5fps. During fast motion, it might spike to 60fps. This saves file size because static portions use fewer frames. Screen recording apps like OBS (in some modes), iPhones, and Android cameras all default to VFR because it reduces storage without obvious quality loss during playback.
The Compatibility Problem
VFR causes real problems in editing. Adobe Premiere, DaVinci Resolve, and Final Cut Pro all expect consistent frame timing. When you drop VFR footage onto a timeline, you get audio drift, where the audio gradually falls out of sync with the video. You might also see dropped or duplicated frames. The fix is to convert VFR to CFR before editing by using a tool like Video to MP4 or running your file through a re-encoding step.
File Size Difference
VFR files are typically 10-30% smaller than CFR equivalents because they skip redundant frames. For screen recordings of mostly static content (like coding tutorials or slideshows), the savings can be even larger. If storage and bandwidth matter more than editing compatibility, VFR is efficient. For everything else, the small size gain is not worth the headaches.
Which One to Use
Use CFR for any video you plan to edit, upload to YouTube, or share professionally. Use VFR only when file size is critical and you will not edit the footage, like quick phone recordings or game captures you will watch once. If you already have VFR footage, convert it to CFR with Compress Video before importing into an editor. For more on frame rates, see 30fps vs 60fps and 24fps vs 30fps.