Browser-only video tools.
No upload.
42 free FFmpeg.wasm tools for compressing, converting, trimming, and editing video — running entirely on your device. Plus 112+ command guides if you want to learn the CLI.
Pick by goal Start from "what do I want to do?"
Popular tools Most-used free tools
Compress video to H.264. Choose from High Quality, Balanced, or Small Size with a quality selector.
Use this tool →Auto-compress video to fit Discord's upload cap (10MB/25MB/50MB/500MB). Bitrate math is handled for you.
Use this tool →Set start, end, width, and FPS to convert any video clip to an animated GIF. Preview and download.
Use this tool →Extract MP3, WAV, or AAC from any video. Listen in the browser and download — no upload needed.
Use this tool →Resize & crop video to any SNS format: TikTok, YouTube Shorts, Reels, Instagram, YouTube, X. Live crop preview. Browser-only, no upload.
Use this tool →Extract JPEG frames at any timestamp. Multi-frame support, JPEG quality, and output size options.
Use this tool →Beginner walkthrough Try them in this order
Reference articles FFmpeg command reference, by purpose
Latest articles FFmpeg command walkthroughs
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FFmpeg: Audio Out of Sync After Converting — Causes and Fixes
Audio and video drifted out of sync only after converting with FFmpeg? Learn why stream copy carries over bad timestamps, why a VFR source breaks sync, and fix it by re-encoding, rebuilding timestamps with +genpts, normalizing with aresample, or forcing constant frame rate.
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Convert HEVC/H.265 to H.264 with FFmpeg — Compatibility
Convert HEVC (H.265) video to H.264 with FFmpeg for old players, video editors, and Windows. CRF quality control, 10-bit to 8-bit yuv420p fixes, copy-audio shortcut, and why H.264 plays everywhere.
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FFmpeg: Fix Audio Drift That Gets Worse Over Time
Audio fine at the start but progressively out of sync by the end? That is drift, not a constant offset. Learn why a clock mismatch or VFR source causes it, why -itsoffset can't fix drift, and correct it with aresample async, then standardize with a fixed sample rate or CFR.
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Reduce Video Size for Email with FFmpeg — Gmail/Outlook
Shrink a video small enough to email with FFmpeg. Hit Gmail's and Outlook.com's 25 MB attachment caps with CRF, downscaling, and a two-pass target-bitrate workflow. Includes the bitrate-from-size formula.
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FFmpeg: Convert Variable Frame Rate (VFR) to Constant (CFR)
Convert a variable frame rate (VFR) video to constant frame rate (CFR) with FFmpeg. Use ffprobe to suspect VFR by comparing r_frame_rate and avg_frame_rate, then force CFR with -fps_mode cfr — the FFmpeg 8.x replacement for the deprecated -vsync cfr. Fixes the root cause of many sync issues.
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AVI to MP4 with FFmpeg — DivX/Xvid/MJPEG to H.264/AAC
Convert old AVI files (DivX, Xvid, MJPEG, MP3 audio) to MP4 with FFmpeg. Re-encode to H.264/AAC with CRF, learn when stream-copy works versus when you must re-encode, add faststart for web playback, plus troubleshooting and FAQ.
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Extract Frames from Video with FFmpeg — Save as PNG or JPG
Extract frames from a video as image files with FFmpeg. Save every frame, grab one frame per second with fps, capture a single frame at a timestamp, and choose PNG vs JPG. Practical guide with quality tips, troubleshooting, and FAQ.
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FFmpeg -c copy vs Re-encode — Stream Copy or Re-compress?
Understand the most important choice in FFmpeg: -c copy (stream copy — lossless, instant) versus re-encoding (lossy, slow, flexible). Learn when each is appropriate, the container compatibility caveat, and runnable commands for both paths.
Quality & privacy Editorially reviewed before publishing
- Local processingVideo / audio tools run in your browser — files stay on-device.
- Primary sourcesArticles cite the official FFmpeg docs and verify against real builds.
- Plain EnglishBeginner-friendly walkthroughs paired with command examples.
- Equivalent CLI commandsEvery tool shows the FFmpeg command it runs internally.