Nsis isn't really designed for 24/7 continuous install making, most projects only create an installer once so the speed doesn't matter much. Like I said, nothing stopping you from writing it yourself, nothing stopped me from making nsisbi in the first place
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On a side note, dealing with codecs is a bit "out of my league". The only reason LZ4 exists in nsisbi is because it has a wrapper layer which just calls the LZ4 api, and converts it back to nsis to make it compatible.