[alternatetwo]

x264 encoded streams have the original encoding parameters included by default.

[fireattack]

Encoding settings metatag can be striped.

Regardless, I don't think these software are "matching" anything. TMPGEnc for example has settings to choose what quality you want for these re-encoded frames.

[_Gyan_]

The parameters being matched would be those that maintain decoder config. Usually, bitrate/quantizer values don't come into that.

[fireattack]

Oh yeah, the level would (should) definitely be kept.