Audio·Video tool
Reduce video size
Adjust the video resolution and encoding bitrate to create a smaller file and compare it with the actual output size.
Processing result
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Reduce video size by running it in the browser
Public example, video is 640×360px, about 4 seconds. The default balance setting targets up to 720p, but small sources are not zoomed in. The actual compression rate depends on video motion, browser encoder, and input codec, and the file size may be larger than the source.
Re‑encode with a new video
Does not upload selected file to the server. Saved in a new container and codec, so input format, quality, and file size may vary. Compare the estimated size with the original and verify directly by playing the result
Bitrate setting is a target value used for output size estimation. The browser encoder does not guarantee accuracy or always produces smaller files.
Limitations on files and devices
Up to 100MB·Works on 60-second videos. Detects the storage format supported by the browser and outputs as MP4 or WebM. Keep the tab open during encoding. Some files may not be processed due to device memory and codec support.
Frequently Asked Questions
Can you precisely specify the desired file size?
Does not guarantee the file size. The estimated value on the screen is a reference figure calculated using the set bitrate, and the actual size is measured after playback. To make it smaller, choose a lower quality setting again for comparison.
Does compression always improve quality or reduce file size?
No. The video is re-encoded in the browser, and the result may become larger or blur compared to the original. Play the result before saving and compare it with the original size.
Is the video uploaded to the server?
No. Only example files are downloaded from the same site, and selected videos are processed in browser memory. Statistics only convey information that the tool was used successfully, without including file names or video content.
Calculation criteria and reference materials
- MDN — MediaRecorder
Re-encoding the capture stream using the browser’s supported container and codec. The supported format and output quality depend on the browser.
- MDN — Canvas captureStream
Draw the current video frame onto the local Canvas and capture it as a video stream for browser recording.
- MDN — AudioContext createMediaElementSource
Connect the audio of video elements to the local Web Audio stream and re-encode it together with the video.
- WebKit — MediaRecorder API
Describes Canvas·Web Audio stream recording and format detection in WebKit implementation. Current device codec support is detected during execution.
Verification of calculation criteria: · Calculation·verification principles · Report errors