MDQC (MetaData Quality Control) is a tool for rules-based comparisons of metadata between assets and user-set templates. MDQC uses ExifTool and MediaInfo to extract technical and descriptive metadata, which can be used to define rule templates and compare large collections of digital assets against these rules.
MDQC was developed and is maintained by AVP.
Paper including case studies on MDQC: "Two Open-Source Tools for Digital Asset Metadata Management" by Alexander Duryee and Bertram Lyons
The source is available on Github