Converting MOV to MP4 makes QuickTime video files compatible with Windows, Android, smart TVs, and web platforms without requiring Apple QuickTime software to be installed. MOV is Apple's QuickTime File Format — a flexible multimedia container that can hold a wide range of codecs including ProRes, HEVC, H.264, and uncompressed video. MP4 (MPEG-4 Part 14) is the universally supported internet standard container, optimised for progressive streaming with the moov atom positioned at the start of the file. When the MOV file already contains H.264 or H.265 video and AAC audio, 1converter performs a stream copy — repackaging the data into an MP4 container in milliseconds without re-encoding, meaning zero quality loss. When the source uses incompatible codecs such as ProRes or Apple Animation, the video is re-encoded to H.264 with configurable quality using the CRF (Constant Rate Factor) method via FFmpeg.