XML (Extensible Markup Language)

XML (eXtensible Markup Language) is a structured text format used throughout post-production to carry editorial decisions, color metadata, captioning and project exchange between disparate software tools. Unlike binary formats such as AAF or OMF, XML is human-readable, version-control friendly and easily inspected with any text editor. The most common XML flavors in post are Final Cut Pro XML (used by FCPX, DaVinci Resolve, Adobe Premiere via translation) which describes a complete timeline including clips, effects and audio levels; Final Cut Pro 7 XML (the legacy variant, still requested by some pipelines for its simpler structure); and various proprietary XMLs from Avid Media Composer (Avid OPATOM XML for ALE-style metadata). Outside editorial, XML carries the ASC CDL (color grading data), IMSC and TTML subtitle formats, DCP composition playlists (CPLs), and IMF master CPLs. The format's strength is interoperability: a Resolve project can be exported as FCP XML, edited in Premiere, then sent back to Resolve for grading with timeline integrity. Its weakness is verbosity and the fact that each vendor's XML schema differs slightly, requiring careful round-tripping tests. Modern alternatives like OpenTimelineIO (OTIO) aim to standardize timeline exchange across tools but XML remains the dominant interchange format in 2025.