Pixel dimensions can be excessive for the place a video will appear. Video Resizer exports a proportional MP4 using the width you choose. It keeps the composition rather than cutting the source to a new aspect ratio, making it suitable when a smaller version of the same frame is the goal.
Choose a width the encoder can use
Select one video no larger than 50 MB. Enter Output width as an even whole number between 32 and 1920 pixels. Odd values are rejected. The height is calculated from the source proportions and adjusted to an even value for the MP4 encoding workflow.
There is no separate height field, crop rectangle, or padding-color control. If the destination needs an exact square or vertical composition, this proportional resize alone cannot choose which part of a landscape frame should remain.
Select Process media. The tool re-encodes video as H.264 MP4 with AAC audio. It uses a fixed quality setting in this workflow, so width is the decision you control. Encoding and metadata characteristics can change even when you choose the same width as the source.
Calculate a landscape example
For a 1920 by 1080 source, choose width 1280. Proportional height is 1280 × 1080 ÷ 1920 = 720, giving a 1280 by 720 output. The entire original frame remains visible at reduced pixel dimensions.
For a portrait source, the height remains proportionally taller than the width. Selecting 1280 does not mean the output becomes a 1280 by 720 landscape. Check orientation and proportions in the preview rather than relying on a familiar width alone.
Download the MP4 and inspect small text, faces, and motion in the actual placement where it will be used. Upscaling a small source adds pixels without recovering missing detail, so a larger width is not automatically a quality improvement.
Compare bytes separately from pixels
Smaller dimensions can be useful, but the output is not guaranteed to be smaller in bytes than an already compact source. Compare the measured sizes and retain the original if it better meets the delivery need. Keep an archival source regardless of which copy you publish.
Processing remains in your browser through a single-thread WebAssembly engine, with a roughly 32 MB initial download. It can consume substantial memory and has a two-minute execution limit. Cancel processing can stop a job; unsupported codecs may require a clean export. Use Video Compressor for adjustable quality, or Video Trimmer to remove unneeded duration before preparing another delivery copy.