Video compression involves a tradeoff between file size and visible detail. ERITHRA re-encodes a small video as H.264 MP4 with AAC audio, letting you choose a CRF quality setting. It does not offer a target-megabyte field or promise that every source becomes smaller.
Set a useful first trial
Choose one video no larger than 50 MB. The file picker accepts common containers including MP4, WebM, MOV, MKV, AVI, and M4V, but the internal codecs still need to be supported by the processing engine. A familiar extension is not a guarantee that every file will decode.
Set CRF quality from 18 to 40. Higher values generally request smaller output at lower visual quality; lower values request more detail. The default 28 is a starting point for comparison. It is not a percentage quality value.
Select Process media and keep the tab open. First use downloads a roughly 32 MB engine. Processing runs in a single-thread WebAssembly worker in your browser, so a desktop browser and short source are practical choices. Cancel processing if you need to stop the operation.
Compare the same source twice
Suppose you have a 20-second, 1920 by 1080 demonstration clip. Export it at CRF 28, then inspect the preview and downloaded MP4. Check small text, camera movement, and sound. Note the measured input and output sizes.
If motion looks too degraded, use the original source again at CRF 23. Compare the two outputs in the same viewer at the same display size. There is no exact predicted byte difference between these settings because scene detail and source encoding affect the result.
The tool does not shorten the clip or deliberately resize it to a smaller delivery width. MP4 encoding requires even dimensions in this workflow, so odd source dimensions are rounded down to even values. For a source already 1920 by 1080, those dimensions remain unchanged.
Keep the version that meets the requirement
A re-encoded output can be larger than an already efficient source. Retain the original if it has better size or quality for your purpose. Metadata and codec characteristics can change, so review playback before sharing.
Files stay in this browser, but processing is memory intensive and has a two-minute execution limit. Damaged or unsupported files may fail. Use Video Trimmer to remove unneeded duration, or Video Resizer when excess pixel dimensions are the main issue. These are separate decisions that may produce a more useful delivery copy.