4K Converter

4K Converter is a private online workbench that uses AI to upscale JPG, PNG and WebP images and short video clips to 4K. Video enhancement is limited to clips of up to 10 seconds, and the tool preserves the original aspect ratio rather than stretching or cropping your files.

It also offers straightforward format conversion for images and video files (MP4, MOV, WebM, AVI, MKV), with a note that conversions change container and codec rather than inventing new detail. The web app is bilingual, available in English and Chinese.

• Exact credit quote shown before each job
• 100 starter credits valid for 30 days
• Uploaded and generated files expire after 24 hours
• Quick, single-file workflow for one-off tasks

Official site: https://www.4kconverter.com/