Video Digital Product Options
For digital products created from video source material, the specifications are dictated to some extent by hardware and software capabilities.
Currently, the Video Preservation Lab creates uncompressed video streams in an AVI (Audio Video Interleaved) wrapper for the SD preservation master product option. All video is ingested on equipment that is calibrated to allow for ITU-R Recommendation BT.601 compliance, but also to allow for safe capture of graphics and other computer-generated materials that may contain luminance values in the superwhite range. This method of calibration and capturing supports the most authentic replication of the original source material.
- The choice of a wrapper was one that NARA staff looked at very critically. According to an in-house international survey conducted in the spring of 2010 of over 50 institutions involved with film and video reformatting, the three main choices for preservation products were AVI, QuickTime (.MOV) or MXF (Material Exchange Format). Each has pros and cons. Based on the feedback we received, NARA has decided to use the AVI wrapper for a variety of reasons including:
- Both the robotic capture system as well as the manual capture system can natively capture in AVI. (Only the robotic capture system has the option to capture in MOV; the manual capture system cannot natively capture in MOV.)
- While the AVI wrapper has somewhat limited support for timecode, we are able to capture a start timecode from which the remainder of a timecode track could be generated if required.
- AVI files are playable in a wide variety of open source tools including VLC.
We will continue to monitor codec and wrapper use within the professional community as well as toolsets development and reevaluate our products as needed, especially when HD video reformatting comes to the fore.
NARA’s options for reproduction masters are in line with peer institutions.