We have recently released a lightweight DPX validator, see: https://github.com/Digital-Preservation-Finland/dpx-validator.
Our aim is to use an efficient way to check that the file most likely is an unbroken DPX file. To make the validation fast enough for fully automated processes, our validator just validates five elements from the DPX header. See details from the README file in Github. Our DPX validation tool is currently in use in the ingest validation in our digital preservation services.