Quick Guide: Understanding AMI Digital Files
For Curators, Exhibitors, and Stakeholders
When requesting digital AMI assets, you will encounter several file types. The file you need depends entirely on what you plan to do with it.
⚡ The “Cheat Sheet”
| If you need to… | Media Type | Request this file | Extension | Status |
|---|---|---|---|---|
| Preview / Stream | Video & Film | Service Copy | .mp4 | Standard |
| Edit / Exhibit | Film | Mezzanine | .mov | Standard |
| Edit / Exhibit | Video | Mezzanine | .mov | By Request |
| Archive / Restore | Video & Film | Preservation Master | .mkv | Standard |
| Listen | Audio | Service Copy | .mp4 | By Request |
| Broadcast / Podcasting | Audio | Edit Master | .flac | Standard |
1. Video Files (Tapes: VHS, U-matic, BetaSP, etc.)
For video tape formats, we typically generate two files by default: the Preservation Master and the Service Copy. If you need to edit or screen the footage in high quality, you must request a Mezzanine file.
Preservation Master (PM) – The “Raw” Archive File
- Format: FFV1 in Matroska (
.mkv) - What it is: A lossless, mathematical copy of the tape signal. It includes all signal noise and typically requires special software (like VLC) to play.
- Best for: Long-term cold storage; deep digital restoration.
Service Copy (SC) – The “Access” File
- Format: H.264 in MP4 (
.mp4) - What it is: A compressed, lightweight file similar to YouTube quality.
- Best for: Research, quick viewing on a laptop, sending via email/web.
⚠️ Mezzanine (MZ) – The “Editing” File (On Request)
- Format: ProRes HQ in QuickTime (
.mov) - What it is: A broadcast-standard file that is highly compatible with editing software (Premiere, Final Cut) and gallery hardware.
- Note: We do not make these by default for video. You must specifically request this if you are building an exhibition or editing a documentary.
2. Audio Files (Reels, Cassettes, Discs)
Audio workflows are unique because we create two high-quality versions: one that is purely raw, and one that is “mastered” for listening.
Preservation Master (PM) – The “Untouched” Capture
- Format: FLAC (
.flac) - The Content: This is the raw transfer with no digital adjustments. It may include long periods of silence (lead-in/lead-out) and volume levels that fluctuate or are very quiet, exactly as they were on the physical carrier.
- Best for: Archiving and evidence.
Edit Master (EM) – The “Listenable” File
- Format: FLAC (
.flac) - The Content: This file has been “cleaned up” by our engineers.
- Trimmed: Heads/tails of silence are removed.
- Normalized: The volume is adjusted to a standard loudness (-23 LUFS) so you don’t have to ride the volume knob.
- Best for: High-quality listening, radio broadcast, podcasting, and publication.
Service Copy (SC) – The “Portable” File (On Request)
- Format: AAC Audio (
.mp4/.m4a) - The Content: A compressed version derived from the Edit Master (so it retains the volume normalization and cleanup) but in a smaller file size.
- Best for: Streaming, sharing with researchers, and listening on mobile devices.
3. Film Scans (16mm, 35mm, 8mm)
Film scans differ significantly between the Preservation Master and the derivative copies regarding what you actually see in the frame.
Preservation Master (PM) – The “Edge-to-Edge” Scan
- Format: FFV1 in Matroska (
.mkv) - The Look: This is an overscan. You will see the entire piece of film, including the sprocket holes, optical soundtrack, and frame edges.
- Color: No color correction is applied; it may look “flat” or faded.
- Best for: Archival preservation and complex restoration.
- Note: Only request this for editing if you require the absolute best quality and are willing to perform manual cropping and color grading from scratch.
Mezzanine (MZ) – The “Production” File
- Format: ProRes HQ (
.mov) - The Look:
- Cropped: Zoomed in to show only the picture area (sprockets removed).
- Corrected: Red fade is removed and color is balanced to look natural.
- Best for: Video editing, documentary production, and gallery exhibition. This provides high fidelity without the extra work of cropping and grading raw scans.
Service Copy (SC) – The “Streaming” File
- Format: H.264 (
.mp4) - The Look: Visually identical to the Mezzanine (cropped and color corrected) but highly compressed.
- Best for: Streaming, quick download, and easy sharing.
4. File Size Estimates (Standard Definition Video)
Most of our video collection is Standard Definition (SD). Film scans (2K/4K) will be significantly larger.
| Content Duration | Service Copy (.mp4) | Mezzanine (.mov) | Preservation Master (.mkv) |
|---|---|---|---|
| 10 Minutes | ~250 MB | ~5 GB | ~6 GB |
| 30 Minutes | ~750 MB | ~15 GB | ~18 GB |
| 1 Hour | ~1.5 GB | ~30 GB | ~35 GB |
5. Summary: Which file should I ask for?
“I just want to listen to an interview for research.”
Request: Service Copy (Audio .mp4) Why: It has all the benefits of the Edit Master (volume normalized, silence removed) but is small and plays on any device.
“I am producing a podcast or radio show.”
Request: Edit Master (.flac) Why: You get the cleaned-up, normalized audio, but in lossless quality that can withstand editing and mixing.
“I’m editing a video documentary using our footage.”
Request: Mezzanine / ProRes .mov (Video) Why: The Service Copy is too low quality for editing. The Preservation Master is too heavy. Note: You must ask us to generate this for you.
“I’m showing a digitized 16mm film in a gallery.”
Request: Mezzanine / ProRes .mov (Film) Why: It is cropped to the picture (no sprocket holes visible) and color-corrected, so it looks best on screen.
“I want to see exactly what was on the original physical tape/film, warts and all.”
Request: Preservation Master
Why: This is the only format that proves exactly what the physical object looked/sounded like before we did any work on it.