What Is an AAF File in Audio Post-Production?
AAF (Advanced Authoring Format) is an interchange format used to exchange editing data between different post-production systems. It's most commonly used to transfer projects from video editing software (like Avid Media Composer or Premiere Pro) to audio post-production systems (like Pro Tools).
What AAF Contains
An AAF file can include:
- Edit decision data: Timeline structure, clip positions, in/out points.
- Metadata: Clip names, timecodes, markers, comments.
- Media references: Links to source media files.
- Embedded media: Optionally, the actual audio/video files can be embedded within the AAF.
- Effects parameters: Some effects and transitions, though support varies.
The AAF Workflow
The most common AAF workflow involves picture-to-sound handoff:
- Picture edit: Editor completes the cut in Avid, Premiere, or Resolve.
- AAF export: Editor exports AAF with embedded audio and guide video.
- Transfer: AAF is sent to the sound department.
- Import: Sound editor imports AAF into Pro Tools or other DAW.
- Sound work: Dialog editing, sound design, mixing.
- Final mix: Delivered back as stems or final mix.
AAF vs OMF vs XML
Several interchange formats exist with different capabilities:
| Format | Best For | Notes |
|---|---|---|
| AAF | Video → Audio transfer | Most comprehensive, widely supported |
| OMF (OMFI) | Legacy audio interchange | Older format, 2GB limit, being phased out |
| XML (FCP XML) | Final Cut Pro interchange | Text-based, human-readable |
| EDL | Simple cut lists | Basic, no media embedding |
AAF File Sizes
AAF file sizes depend on whether media is embedded:
- Links only: A few MB (just metadata and references).
- Embedded audio: Can be several GB for a feature film.
- Embedded video: 10-50+ GB depending on length and codec.
For a typical feature film audio turnover, expect AAF + reference video to be 5-20 GB.
Common AAF Issues
- Missing media: If media isn't embedded and paths don't match, files won't link.
- Sample rate mismatch: Audio must be converted if rates don't match.
- Effect incompatibility: Many effects don't translate between systems.
- Codec issues: Receiving system must support the embedded codec.
Transferring AAF Files
AAF transfers are a critical handoff point between departments. Late or corrupted AAFs can delay sound work and final delivery. Handrive makes AAF transfer simple:
- Direct P2P: Send AAF directly to the sound team without cloud upload.
- No size limits: Transfer large AAFs with embedded media without restriction.
- Free: No per-GB fees for turnover after turnover.
Learn about file transfer for post-production workflows:
Freelance Editor's Guide to Receiving and Delivering Files →