Astra vs NextGenUp

Astra has no write-up on Specifiction yet; its figures are above.

NextGenUp is a free tool for enlarging images and video, available as desktop software for macOS, Windows 10/11 and Linux, or as a self-hosted web app. Processing runs on the user's hardware: its models, FFmpeg and server run locally, and files are not sent to cloud processing. Images can be enlarged to 8K using Quick, Quality, Enhance or Ultra modes; video upscaling reaches 4K through basic and professional AI modes. Enhance reduces noise and blur without enlarging the image, while GFPGAN v1.4 detects faces and restores detail. Real-ESRGAN handles super-resolution. Processing uses the CPU by default and accelerates with a GPU when available. The browser app can use WebGPU on Chrome or Edge 113 and later. The software is MIT licensed and needs no subscription, watermark or account. There is no trial limit. Web files are limited to 2 GB, and older processed files are automatically removed after 24 hours. PNG is the listed output format.