To help you solve this, could you share or if there is a specific website they are associated with?
They might be unique identifiers for a specific hosting service (like Mega, Google Drive, or YouTube). If you found these on a forum, they are often intended to be appended to a specific base URL provided in that community's "Key" or "Sticky" post.
Sometimes these strings are encoded. However, "Q2e5w3vltl" and "RvJI6sfEl6" do not decode into standard English text via Base64, suggesting they are either random hashes or part of a proprietary naming convention.
Because these specific strings do not return results in standard search indexes, "putting together the piece" likely refers to one of the following scenarios:
These could be parts of a split archive (e.g., .001, .002). If you have the physical files, you would typically use a tool like 7-Zip or WinRAR to "Combine Files" or extract the first part to reconstruct the full .mp4 .