HEVC (High-Efficiency Video Coding / H.265). This compression standard allows for high video quality at a significantly lower bit rate/file size compared to older standards like H.264. HEVC (High-Efficiency Video Coding / H
.mkv (Matroska Video File). This is a flexible container format that supports multiple audio tracks and subtitle streams.
Files from unverified sources can occasionally be "wrappers" for malware or adware, though .mkv files are generally safer than .exe files.