This option can be used when the file is expected to be used primarily in an online access capacity such as through ARC.

Any digital reproduction master file from video source material.

Container

• Windows Media WMV

Target Total Bitrate: ~1.1 Mbps

Timecode: Source LTC/VITC

Video data:

• Video frame size: 720 x 480 non-square pixels
• Aspect ratio: 4:3
• Video codec: Windows Media Video 9 (VC-1 compliant as defined by SMPTE 421m and 421m-Am1)
• Video bitrate: ~1.0 Mbps
• Video mode: CBR
• Video frame rate: 29.97 fps or 60fps (some source material needs to be converted to a 60fps frame rate due to a flicker artifact introduced during various format conversions)
• Key frame rate: 5 seconds
• Progressive scan
• Single-pass encoding

Audio data:

• Audio channels: 2 (stereo L R)
• Audio bitrate: 128 Kbps
• Audio mode: CBR
• Audio codec: Windows Media Audio 9.2
• Audio sample rate: 48 KHz
• Audio sample size: 16 bit

Typical file size: 6.78 MB/minute or .407 GB/hour

None

This is the current standard for ARC/OPA for all digital moving images.

Audio and video levels may be adjusted as appropriate during the initial capture process but otherwise, the preservation files are unaltered. Reproduction and distribution files may have additional image improvements such as minimal color correction if necessary.

The Digitization Services Branch’s Quality Assurance and Quality Control (QA/QA) program is evolving as new tools and resources are acquired and implemented. We are moving towards more automated and integrated systems to assure the products we make meet the specifications outlined. Digital products created by the Digitization Services Branch are validated against standardized format specifications and signature files when possible. We use a variety of format specific batch evaluation and validation tools both open source and vendor supplied, to assure technical quality level specifications are met. All files, but especially distribution system specific files, are inspected for successful playback in a variety of tools and environments. Additional quality control workflows are in development.

Equipment/System Evaluation
NARA implements scheduled service and calibration protocols according to manufacturer recommendations as well as on an "as needed" basis.

Metadata
Embedded metadata: NARA is working on embedded metadata guidelines for all file types.
Technical metadata: NARA is finalizing technical metadata schemas for all file types.

NARA is developing an in house job tracking order system to better coordinate work at the Branch level.

Item Level Evaluation: Automated File Characteristics Analysis
Fixity: NARA is evaluating workflows to create and validate checksums for each digital file.