The most important trimming detail is whether a field expects an end time or a duration. ERITHRA asks for the start in seconds and the duration to export. Adding them gives the requested end point. Planning that interval first avoids cutting a much longer or shorter section than intended.
Enter a valid interval
Choose one video up to 50 MB. Enter a start at or above zero and a duration between 0.1 and 600 seconds. The start must be inside the source, and the requested section must not run beyond its end.
Before processing, the browser reads the file’s duration metadata. This requires a finite positive duration in a format the browser can inspect. A file that the media engine might otherwise decode can still fail this timing check. Re-exporting it to a conventional MP4 or WebM may provide readable metadata.
Select Process media and keep the tab open. The export is a re-encoded H.264 MP4 with AAC audio, rather than a guarantee of copying the original compressed streams unchanged. The output can therefore differ in size, quality, metadata, and exact encoding characteristics.
Calculate a twenty-second clip
Suppose the source lasts 90 seconds and the useful action runs from second 12 through second 32. Set Start time to 12 and Duration to export to 20. Entering 32 as the duration would instead request a clip ending at second 44.
For the same source, start 80 and duration 20 exceeds its 90-second length and is rejected. Choose an earlier start or a shorter duration before retrying. Do not rely on the tool to silently truncate an invalid request at the source’s end.
After export, watch the first and last few seconds and listen for cut-off speech. A mathematically valid interval may still begin halfway through a word or end before an action is understandable. Adjust the numbers using the original source and generate another copy if needed.
Allow for browser processing limits
The roughly 32 MB engine downloads on first use and runs in a single-thread WebAssembly worker. Processing stays in your browser, can use substantial memory, and has a two-minute execution limit. A short input is more practical than a large high-resolution recording near the file-size ceiling.
Use Cancel processing to stop a job. Unsupported codecs, damaged files, or unreadable timing information can require a clean source export. Keep the original until the clip is checked. Use Video to GIF for a brief looping visual, or Video Compressor when the finished MP4 needs a separate quality-and-size comparison.