Deduct audio id / timestamp by fixed value to mark them as custom content

[SciLor]

Within TeddyBench and TeddyCloud we detect custom encoded content if the audioid is below 0x50000000.
When encoding custom content we always deduct the audioid by 0x50000000.

Why?

We need a mark to detect custom content, as we are also maintaining the tonies.json to detect tonies by audioid. If people send us new SHA/audioids (report function in TeddyBench) we are otherwise unable to see it was official content or content encoded with a third party tool.
Creative Tonies are also a problem, but there is nothing we can change.

What is your opinion? Maybe you already have some marker we could detect?