Load a video, then set the range, resolution, and format
Converts using codecs supported by your browser and creates a new file on your device.
Browser save support
Input/output format support varies by browser and OS. Unavailable options are disabled.
Video & audio files
Files are not uploaded.
Conversion & Compression Settings
Selecting a file shows an estimated output size.
Conversion status
Keep this tab open during conversion.
Video and audio are processed only in your browser.
What you can do with the video/audio converter and compressor
Load a local video, set start/end, resolution, frame rate, video bitrate or target size, and convert to WebM or MP4 (where supported). Short segments can be converted to GIF animation, and audio tracks can be extracted as WAV.
No large conversion libraries are loaded externally; we use the browser’s built-in video and audio features. Thus, input/output codecs depend on the environment, but availability is shown before conversion, and files are never sent to a server.
Keep resolution and aspect ratio
Choose original size, 1080p, 720p, 480p, 360p, or custom width; dimensions are adjusted to even pixels.
Calculate from target size
Calculates the video bitrate from the selected duration and target MB, then clamps it to a realistic range.
Show supported formats
Indicates whether WebM, MP4, GIF, and WAV can be saved in your current browser.
Generate short GIF on device
Limited to 12 seconds and 640px wide to prevent memory issues and oversized files.
Steps to reduce video resolution and file size
- Choose videoCheck that the video plays in the browser, plus its length, resolution, and size.
- Specify only needed rangeShortening the start and end range helps reduce file size while keeping quality.
- Choose resolutionFor attachments or internal sharing, consider 720p or 480p; use original resolution if fine text detail is needed.
- Set quality or target sizeThe target size is approximate; actual output size varies with video content and encoder.
- Preview converted fileCheck video, audio, start/end, and text readability, then store separately from the original file.
WebM vs MP4
| Format | Features | Note |
|---|---|---|
| WebM | Easy to save in-browser with Chrome, Edge, and Firefox | May not play in older Office or some devices |
| MP4 | High compatibility for business software, smartphones, and documents | MediaRecorder MP4 output depends on the browser and OS |
| GIF | Easy to share short silent animations as images | 256 colors, no audio; not suitable for long or high-quality clips |
| WAV | Save audio uncompressed for easier editing | Large file size; decoding audio in video depends on the environment |
Why MP4 save isn’t available
MP4 is not an extension but a container that holds H.264 video, AAC audio, etc. Even if a browser can play MP4, it may not be able to create MP4 via MediaRecorder. This tool checks actual support and disables the option if unsupported.
If you need MP4 and it’s unsupported, save as WebM and convert using your OS’s built-in or trusted video editing software. Changing only the extension to .mp4 does not change the format and will cause playback issues.
How to think about target size and bitrate
Approximate size is calculated as bitrate × seconds ÷ 8. For example, 2.5 Mbps video for 60 seconds is about 18.8 MB for video alone. Actual size includes audio, container overhead, and encoder variations.
Specifying a target size does not guarantee exact match. Fast motion, fine text, or noisy video degrades quality more at the same bitrate. For strict size limits, convert with a slightly smaller target and verify.
GIF conversion limits
GIF cannot store audio and is limited to 256 colors per frame. To reduce device load, this tool limits to 12 seconds, 640px width, and 4, 6, or 10 frames per second. It’s suitable for short UI demos or email attachments showing motion.
Color banding is noticeable in photos and gradients. For long videos, use WebM or MP4 and trim only the needed parts. During conversion, each frame is held in memory, so closing other heavy tabs helps stability.
Audio extraction & codecs
WAV audio extraction works when the Web Audio API can decode the input file’s audio track. Even if the video plays, some browsers cannot decode the entire container as audio, causing extraction to fail. In that case, use a copy in another format or dedicated software.
DRM-protected, encrypted streaming, or URL-based videos are not supported. This tool only processes files you select on your device.
Handling large videos and device memory
Conversion takes roughly the same time as the video duration; locking the screen or switching tabs may pause or slow it. 4K, long, or multi-GB videos are not suitable for browser processing. Try a short range and lower resolution first.
This tool does not load a large WASM conversion engine, keeping initial load and device storage low. However, it does not guarantee all input/output formats. For professional videos beyond its scope, use desktop editing software.
Processing without uploading video or audio
File reading, playback, frame drawing, re-encoding, GIF creation, audio decoding, WAV creation, and saving are all done in the browser. Video and audio are never sent to WiseChecker servers or external APIs. Reloading the page discards temporary URLs and conversion state.
Video & audio conversion FAQ
Can I always save MP4 as MP4?
Not possible. MP4 output depends on browser MediaRecorder support; if unsupported, the option is disabled.
Will it be exactly the target size?
It will not. This is a guide to estimate bitrate from duration; actual size varies with content and encoder.
Can GIF include audio?
No. GIF is an image format.
Can I open another tab during conversion?
Background processing may be throttled, so keep this tab in the foreground.
Is the video sent to a server?
No upload. Processing happens in your browser.
Does conversion change the original file?
No. It saves as a new file.