Overview map for matching picture and audio tracks — indicates which takes must run in sync.
Technical Details
A Sync Map contains frame-accurate timecode references (SMPTE 12M standard) and links original audio BWF files with corresponding picture sequences via shared metadata. Modern systems utilize Tentacle Sync generators (±0.1ppm accuracy) or PluralEyes algorithms, which perform waveform matching with a 48kHz sampling rate. The map files are exported as XML or EDL (Edit Decision List) and additionally contain drift correction data for cameras without Genlock synchronization.
History & Development
The first computer-based sync technology was developed by Avid in 1989 with the Media Composer, which replaced manual clapper synchronization through waveform analysis. In 2006, Singular Software revolutionized automatic synchronization with PluralEyes through audio fingerprinting. Red Giant acquired the technology in 2013, while concurrently, Tentacle Sync introduced hardware-based solutions with Bluetooth networking in 2014. Since 2019, AI-based systems like DaVinci Resolve's Auto Sync have enabled 95% hit rates even with poor audio quality.
Practical Application in Film
On "1917" (2019), Roger Deakins' team synchronized over 2,000 takes from 47 different cameras using a master sync map that linked all Steadicam and drone footage with frame accuracy. Multi-camera productions like "The Crown" use up to 12 cameras simultaneously daily, with sync maps automatically generated from embedded timecodes. Documentary workflows utilize proxy sync maps at 1/4 resolution for quick pre-editing before the final 4K masters are synchronized.
Comparison & Alternatives
Sync Maps differ from simple EDLs through bidirectional references and drift compensation. Timecode synchronization requires hardware Genlock, while audio sync maps also work with consumer cameras without timecode. Adobe Premiere Pro's Auto-Sync operates on a project basis, while Final Cut Pro X creates permanent compound clips. For live productions, hardware Genlock systems like the Blackmagic Sync Generator completely replace post-synchronization.