toolgarden.xyz
中文

Video Compressor

Shrink video file size in your browser with three quality presets and downscaling to 1080p, 720p or 480p, re-encoded to H.264 MP4 with audio kept.

video_compress.preview_title

Compression settings

Quality preset
Output resolution

Only process videos you own or are authorized to edit. Compression runs entirely in your browser; nothing is uploaded and data is cleared when the page closes.

Output video

The compressed video will appear here

About this tool

Video compression re-encodes your video locally in the browser: WebCodecs hardware-encodes to H.264 MP4 at a bitrate chosen by the quality preset, optionally downscales the long side to 1080p / 720p / 480p, and re-encodes the audio track to a matching bitrate with a local ffmpeg pass.

Compression is re-encoding, not magic: the lower the bitrate, the smaller the file and the more visible the quality loss. The medium preset covers most sharing scenarios; the low preset is for when watchability is all that matters.

The video is never uploaded; everything runs on your device and data is cleared when the page closes.

How to use it

  1. Upload a video

    Common formats such as MP4, WebM and MOV, up to 5 minutes and 300MB.

  2. Pick quality and resolution

    Check the size estimate first: downscaling usually shrinks files more than lowering bitrate.

  3. Render and download

    Preview the result before downloading; switch presets and re-run if the quality is not right.

Supported range and limits

Output
H.264 MP4 (AAC audio)
Quality presets
High / medium / low bitrate factors
Resolution
Original, or long side capped to 1080p / 720p / 480p
Limits
300MB and 5 minutes per file
Encoding pipeline
WebCodecs drives hardware H.264 encoding; ffmpeg.wasm re-encodes the audio
Privacy
Everything runs locally in the browser; the video is never uploaded

When you would use it

  • Sending large files

    Shrink a video below a chat app limit — start by reducing resolution.

  • Saving storage

    Archive old footage at 720p medium quality; files typically drop to a fraction of the original size.

  • Faster uploads

    Pre-compressing before upload cuts waiting time on slow connections.

What to know before you start

  • Compression is lossy: compressing an already-compressed video stacks the loss, so start from original footage.
  • The size estimate is a bitrate-based reference; motion and noise in the footage significantly affect the real result.
  • Output is always H.264 MP4 for compatibility; if audio muxing fails for some formats, the result is silent and labeled as such.

Related concepts

Bitrate
Data used per second of video; the core trade-off between size and clarity.
H.264 / AVC
The most widely compatible video codec; WebCodecs drives hardware encoders to produce it in-browser.

Frequently asked questions

Can I target an exact file size?
The tool works with quality presets rather than exact byte targets. Try the medium preset, check the real output size, then step up or down; one or two rounds usually finds the right preset.
Why does quality drop noticeably?
The bitrate factor decides how much data each pixel gets. The low preset trades detail for size, and fast motion shows blocky artifacts first; use the high preset at original resolution for quality-sensitive footage.
Is the audio kept?
Usually yes: the audio is re-encoded to AAC at a bitrate matched to the preset. If muxing fails for some formats the export is silent, and the result panel labels it.

Related tools