File-based IMX50 is MXF-wrapped MPEG-2. (It's also standard-definition -- ewww...)
I think AE should read it natively.
I did a quick test, using Adobe Media Encoder to create an MXF OP1a file with the IMX50 preset. It read perfectly into AE. It might be worth testing with your ingest system, but it really ought to just work.
Walter Soyka
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