: Most commonly H.264 (AVC) or H.265 (HEVC) , which allows for high quality at a relatively small file size.
: Sites that aggregate public-domain or creative commons videos often retain the original camera filenames. Technical Profile of an MP4 File
: Sites like Shutterstock, Adobe Stock, or Pond5 often use internal alphanumeric codes to catalog clips. This specific ID might refer to a high-definition (HD) or 4K background clip used by editors.