How It Works
From file to ready-to-share video in four steps — entirely in your browser.
A file from your device, in your browser.
A preset or advanced controls.
Locally in your browser, via WebAssembly.
Save your optimized video.
The arrows are local data flow — the source video never leaves your device in the normal workflow.
Which tool should you pick?
Not sure where to start? Both tools share one engine. The difference is how the presets are tuned.
Video Encoder
Full control for format and quality
- Pick codec, container, resolution, aspect and frame rate
- Social presets for Reels, Shorts, TikTok and more
- Quality levels plus custom bitrate and encoder speed
- Copy mode to change containers without re-encoding
Video Compressor
Simple presets to shrink file size fast
- Four straightforward modes: High Quality, Balanced, Small, Maximum
- Balanced is the recommended daily driver
- Great for email, chat apps and upload limits
- Same local, browser-based engine underneath
The settings, in plain English
You do not need to touch these. When you do, here is what they actually mean.
H.264 is the safest choice — it plays everywhere and is always available. HEVC gives smaller files but needs a modern device. VP9 is open and efficient but slower, usually paired with WebM. This build has no AV1 encoder. "Copy" skips re-encoding entirely.
The "envelope" for video: MP4 for maximum compatibility, WebM for an open, browser-friendly file, MKV for desktop players. The container is switched automatically if it conflicts with your codec.
Keep the original size, step down to 1080p/720p/480p/360p, or set custom dimensions. Aspect ratio and fit (fit, crop or stretch) control how vertical or square content is framed — 9:16 for Reels and Shorts.
The number of frames per second, from original through 24, 25, 30, 50 and 60. Lower frame rates shrink files; 30 FPS is standard for social feeds.
A quality level (High, Balanced, Small, Maximum Compression) maps to a CRF value for H.264. Lower CRF means better quality and a larger file; the levels pick sensible values so you rarely need exact numbers.
An optional fixed bitrate for the video stream, in kbps (for example 4500). Leave empty to let FFmpeg decide from the quality level — that is usually the better choice.
AAC is the common choice for MP4, Opus is great for WebM, and MP3 or Vorbis are options for MKV. You can also copy the original audio untouched or remove it entirely.
A speed-versus-efficiency trade-off, from ultrafast to veryslow. Faster encodes finish sooner but produce larger files. The presets default to a sensible middle ground.
What affects speed and file size
Four things decide how long encoding takes and how big the result is.
Your hardware
Faster CPUs and more RAM mean shorter encodes. Encoding runs on your device, so your machine sets the pace.
Resolution & duration
4K and long videos take more time and memory. Downscaling to 1080p or 720p helps a lot.
Codec & quality
Smaller output usually means more encoding work. Higher efficiency and lower CRF cost time.
Encoder speed
Ultrafast finishes quickly but grows the file. Veryslow squeezes the smallest file but takes far longer.
Practical tips
- Use Balanced or a social preset first — they are tuned to look good without fuss.
- Compress before sending videos over WhatsApp, email or apps with upload limits.
- Use Copy mode when you only need a container change — it is instant and lossless.
- Pick 9:16 and a social preset for Reels, Shorts and TikTok instead of resizing manually.
- Close other heavy tabs during long encodes to avoid memory pressure.
- Stick with H.264 if you will share the file, publish it, or open it in editors.
- Export 1080p for the web — the quality is nearly indistinguishable and the file is much smaller.
- Very large files use lots of browser memory; smaller chunks are more reliable.
Full support. Recommended for the fastest encoding.
Full support. Slightly more conservative memory use.
Supported. Encoding may be slower than Chrome.
Supported, but encoding can be much slower. Keep files small.