NDSA:Standards and Best Practices Working Group/Optical MeetingNotes

Meeting minutes - NDSA Standards and Practices, September 15, 2014

Minutes: Lauren Sorensen, email me with any changes/updates

Kate Murray: Ranking stumbling blocks for video preservation, put a call out to NDSA members, meeting on 26th of Sept. Contact Kate at kmur@loc.gov to join for meeting details

Andrea Goethals: next call S&P call will be on October 20th - continue discussion on optical media 1-2pm.

August 25th, a closed meeting happened about preserving and accessioning email records; attendees included Stanford, Harvard, NARA. Interest in opening this up to any NDSA members working with this material, aim to host listservs and list of toolsets. Coming soon: Signal blog post from Chris Prom about this meeting.

Different aspects of optical discs; still interest in our group. Welcome anyone working in this area to contribute to discussions.

Speakers today: Michelle Youket (LOC), Alex Duryee (AVPS), Morgan Morel (George Blood Audio & Video).

Michelle Youket (LOC)
- Goal is to develop strategies for preservation of optical media
- Natural and accelerated aging
- 1996 - pilot study - 125 random optical discs were selected from LOC collections
- Monitor effects of storage and use
- Later expanded to 1200 discs and wide range of dates of manufacture
- Follow 1SO 18921 standard
- Adhesive labeled disc after 1000 hours aging error rates higher
- Measured effects of laser engraving
- CD-R more stable than DVD - larger size of data pitch for CD, more data to be corrupted in a smaller area with DVD.
- Dye and reflective composition - significant factor in degradation - gold more stable than silver.
- Cyanine, meant as long strategy dye.
- Phthalocyanine - at times, hard to differentiate upon inspection.
- LOC created error checker software as an assessment tool.
- JVC archival disc system error checker disc drive
- Disc-to-disc migration
- Burn tests
- Report fields: media / brand / dye / jitter

Alex Duryee (AudioVisual Preservation Solutions) @archivetype
- Article, meant to be intro to optical disc preservation: http://www.avpreserve.com/wp-content/uploads/2014/04/OpticalMediaPreservation.pdf
- Research being done by colleagues - studying preservation of physical media but little information exists about the process of extraction and logical structure of what is on a disc.
- What is on this disc? How to view and assess? There is no go-to process for examining.
- Precedent is law enforcement - however, few criminals use CDs and optical discs so often not supported by forensics tools.
- 92% migration failure rate for data extraction.
- Researching discs as carriers of data.
- Two major types of discs - audio and data
- Audio: one of first uses of consumer optical media - designed to replace 8 track
- Instead of filesystem paradigm these discs featured a single stream of modulated data running uninterrupted throughout the disc, with byte level metadata, such as track names.
- Audio CDs more akin to tapes and vinyl because of this uninterrupted stream - only metadata differentiates “pieces” on the CD.
- The human ear is bad at detecting small errors - CD audio standard is 44.1khz - 16 bit depth.
- Even the best consumer/ professional hardware has a 98-99% accuracy in a given read - not good for preservation, as don’t know if you’re getting what you need - is it capturing important metadata?
- CD-ROM/ data CDs - ISO 9660 - Similar to audio discs except broken to sessions and tracks
- See it in a file browser and directories - convenient for archivists, what you see is what you get.
- Data cds can contain multiple filesystems - older, early mid-90s HFS file systems were common.
- Can contain all 3 filesystems and operating system used to extract data will default to one it can read. So: sometimes the OS can’t see the filesystem.
- UDF filesystem started being used, manufacturers getting together to consistently use this filesystem.
- ISO Buster - tool for this filesystem breakdown.
- Other projects
  - Cabrinety Collection
  - WNYC - Audio disc project
Morgan Morel (George Blood Audio & Video) @av_morgan
- 500 once written DVDs - American Folklife Collection Veterans History Project.
- Staff at vendor asked to create findings report; outlining troubles and tools used.
- Formats for medium term storage white paper; ISO disc image recommended.
- ISO disc image can be mounted filesystem as if it were inserted into drive
- Extract production master files
- VideoTS folder and AudioTS folder
  - [Going through folders as they appear:] VideoTS is all video content - IFO is info about playback and navigation
  - VOB - audio and video data _0 menus - limit to 1GB content - need to connect to make more than one to make it playable
  - All folders listed needed to be intact
- CLI: *ended up using most for project on-site at George Blood.
  - hdiutil*
  - dd
  - ddrescue*
- GUI:
  - Mediagrabber
  - DVD Decrypter
  - Used hdutil and ddrescure - powerful for automated systems run from server
  - make workable iso images in case of damage etc
- Tools for extraction: *ended up using most for project on-site at George Blood.
  - GUI: compressor, handbrake, mpegstreamclip, streamz
  - CLI: FFmpeg*
- Out of 500 DVDs, 49 were problematic
- 9 had physical issues - ok after polishing
- Cloning errors for rest - ddresue could still make working ISO images
- 31 were DVD-ROM instead of DVD-video.
- http://www.digitizationguidelines.gov/audio-visual/documents/IntrmMastVidFormatRecs_20111001.pdf

John Passmore (WNYC) @WNYCarchives
- 30,000 CD-DA - CD-Rs with encoded audio
- Created in early 2000s by WNYC staff
- Considered preservation masters for that era
- Group of CDs were made using same machines, same brands of discs, so in a sense a control group
- CDs function as material for the reference library for a long time - Librarians noticed that pulling CDs some were not playing, ripping properly, determined a need to get data off of the CDs ASAP, purchased equipment and made a RIP station.
- Ripped about 8k CDs, dumping wav files at digital asset management station, cataloging.
- First wanted to test some to learn about increase in errors and condition of collection.
- Plextor drives used.
- Large spectrum of discs regardless of year they were from and different levels of accessibility.
- 2400 Mitsui silver CD-Rs
- 20% of silver cds measuring previously detectable errors
- None passed IASA’s specs for errors - technicians instead looking for what CD is getting kicked out and why.
- Not gradual increase based on date - totally random variables
- Conclusion: CD-DAs don’t last long and are unpredictable, accelerating aging only part of issues with optical media - hardware to make data, care and handling etc.
- More open source solutions would be great to use with hardware that exists
- Contact John Passmore at WNYC: jpassmore@nypublicradio.org

Kate: Running out of time, John Spencer will present on MDisc at next month's meeting.

Discussion
- Spencer: Plextor: only been a year that current iteration of the company has been making their own drives and have dropped support for some of their software tools.
  - Observation that understand nature of companies - rebranding burners.
- Passmore: Optidrive (?), other software
- Duryee: Secondary market now for equipment - price spike in true quality plextor drives - going for a lot used before bought by another company (current iteration of brand).
- Blood: we’re always talking about a system - drive from trusted manufacturer, CD that isn’t playing, sometimes a cheap player can help resolve playability issue.
- Youket: differences in disc composition - many different dyes with different patents - that’s why focus was on developing and using error checkers.
- Blood: Interest in how to optimize burn speeds to get low error rates. Batch variation: Mitsui sold 4 times in 5 years.