Why Google Drive Can Break a DCP
A DCP is a folder of files — picture MXF files, audio MXF files, and XML files that reference every other file in the package by its exact name, character by character. If a filename changes, the XML map no longer matches. The DCP is broken.
Google Drive silently renames large files — particularly MXF files above a certain size threshold — automatically, without notification, without any visible indication. The folder looks normal on Google Drive. But the XML map inside it now points to filenames that no longer exist. The cinema server attempts to ingest, every file fails its XML reference check, and ingest fails with no clear explanation.
If you must use Google Drive: zip the entire DCP folder before uploading. The zip archive protects the filenames from being altered. Unzip at the other end and the DCP should be intact. The same caution applies to OneDrive and some versions of iCloud Drive.
UDP vs TCP — Why It Matters for Large Files
Standard internet file transfer — the technology behind Google Drive, Dropbox and WeTransfer — uses the TCP protocol. Every packet of data sent via TCP requires an acknowledgement from the recipient before the next packet is sent. Over long distances, the time those acknowledgements take to travel back and forth creates a serious bottleneck for large files. Both ends can have excellent internet connections and still achieve a fraction of their potential speed.
UDP-based transfer does not wait for acknowledgements before sending the next packet. It pushes data continuously, handling error-checking separately. For large DCP files over long distances, the speed difference can be enormous.
What We Recommend — Filemail
For DCP delivery, we recommend Filemail. It uses UDP acceleration built specifically for large file transfer, imposes no restrictions on file size or type, includes download tracking (so you know when the cinema has received your film), and is straightforwardly priced for independent use. The recipient does not need to register or install anything to download. Our affiliate link is on the website.
Enterprise UDP services like Aspera and Signiant are used in professional broadcast pipelines but are priced for large organisations with ongoing high-volume needs — not practical for independent filmmakers. MASV and File.io are more accessible alternatives with transparent pricing.
Long-Term Storage
Keep a copy on at least two separate physical drives in different locations. Keep a copy in online storage — zipped if using Google Drive. Note the DCP's checksum values so you can verify stored copies in future. And keep the source material the DCP was made from — your ProRes or DPX master — because recovering from original files is always preferable to reverse engineering from a DCP.
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