PDF/A is a constrained subset of PDF designed for long-term preservation. This field guide walks through the four pre-flight checks (XMP metadata, encryption, font embedding, forbidden features) that decide whether a document will pass a real archival conformance test before you ever upload it to VeraPDF.
Your audio and video files already carry a JSON manifest with codec, bitrate, encoder, chapters, color space, and 30 to 80 other fields per stream. Here is how to read that JSON, why ffprobe surfaces fields players hide, and four everyday cases where reading the manifest ends a guessing game.