Some older digital cameras or screen recording software use alphanumeric prefixes (like "G") followed by a sequence number. "g125.mp4" would simply be the 125th video recorded on such a device. General MP4 Characteristics
If this is a standard video file you have encountered, it likely shares these traits: g125.mp4
The term "G125" and "MP4" are frequently associated with mobile graphics units, specifically the ARM Mali-G Series (e.g., Mali-G76 MP4 or Mali-G57 MP4 ). A file named "g125.mp4" may be a specific test video used to benchmark the performance of these 4-core (MP4) mobile GPUs. Some older digital cameras or screen recording software