Preserving Digital Sound and Vision: A Briefing 8th April 2011

Last Friday I went along to the DPC briefing Preserving Digital Sound and Vision. I was particularly interested in the event because of digital video files currently held on DVD media at the Bodleian.

After arriving at the British Library and collecting my very funky Save the Bits DPC badge I sat down to listen to a packed programme of speakers. The morning talks gave an overview of issues associated with preserving audio-visual resources. We began with Nicky Whitsed from the Open University who spoke about the nature of the problem of preserving audio-visual content; a particularly pertinent issue for the OU who have 40 years of audio-visual teaching resources to deal with. Richard Ranft then gave a fascinating insight into the history and management of the British Library Sound Archive. He played a speech from Nelson Mandela’s 1964 trial to emphasise the value of audio preservation. Next Stephen Gray from JISC Digital Media spoke about how students are using audio-visual content in their research. He mentioned the difficulties researchers find when citing videos, especially those on YouTube that may disappear at any time! To round off the morning John Zubrycki from BBC R and D spoke about Challenges and Solutions in Broadcast Archives. One of the many interesting facts that he mentioned was that subtitle files originally produced by the BBC for broadcast have been used as a tool for search and retrieval of video content.

After enjoying lunch and the beautiful sunny weather on the British Library terrace we moved onto the afternoon programme based on specific projects and tools. Richard Wright of the BBC spoke about the Presto Centre and the tools it has developed to help with audio-visual preservation. He also spoke about the useful digital preservation tools available online via Presto Space. Sue Allcock and James Alexander then discussed the Outcomes and Lessons learnt from the Access to Video Assets Project at the Open University which makes past video content from the Open University’s courses available to OU staff through a Fedora repository. Like the BBC, discovering subtitle files has allowed the OU to index their audio-visual collections. Finally Simon Dixon from the Centre for Digital Music Queen Mary University spoke about emerging tools for digital sound.

A final wide ranging discussion about collaboration and next steps followed which included discussion about storage as well as ideas for a future event addressing the contexts of audio-visual resources. I left the event with my mind full of new information and lots of pointers for places to look to help me consider the next steps for our digital video collections… watch this space.

The Case for Digital Preservation

Now, I'm pretty sure there is no need for me to make the case to the good readers of this blog, but if you're ever stuck for something to say about why your work is important - for example at parties - then the demise of the print edition of the OED seems a good candidate!

OK, so no one is about to ditch the Pocket version, or even the Shorter (I got one of those for a graduation present from my Grandma!), but even so...

The last print OED was published in 1989. I imagine, given the regular updates to the OED online, that there has been a substantial influx of words since 1989 and I guess (given how Chaucer looks now) English will undergo some significant changes in the future. Unless we (the DP community) decide to preserve the digital OED, we will condemn readers of 2489 to struggle on with an antique 1989 print copy and much will they wonder when they don't find things like "Internet"...

(Mind you, the electricity might have all run out by then so it wont really matter...)

On the flip side, and no doubt something someone at the party will point out, this is also a case for continuing to print the OED - at least a few copies, kept in safe places... ;-)

Par2ty

This is probably an old and battered hat for you good folks (seeing as the Web site's last "announcement" was in 2004!), but most days I still feel pretty new to this whole digital archiving business - not just with the "archive" bit, but also the "digital preservation", um, bit so it was news to me... ;-)

Perusing the latest Linux Format at the weekend, I chanced on an article by Ben Martin (I couldn't find a Web site for him...) about parchive and specifically par2cmdline.

Par-what? I hear you ask? (Or perhaps "oh yeah, that old thing" ;-))

Par2 files are what the article calls "error correcting files". A bit like checksums, only once created they can be used to repair the original file in the event of bit/byte level damage.

Curious.

So I duly installed par2 - did I mention how wonderful Linux (Ubuntu in this case) is? - the install was simple:

sudo apt-get install par2

Then tried it out on a 300MB Mac disk image - the new Doctor Who game from the BBC - and guess what? It works! Do some damage to the file with dd, run the verify again and it says "the file is damaged, but I can fix it" in a reassuring HAL-like way (that could be my imagination, it didn't really talk - and if it did, probably best not to trust it to fix the file right...)

The par2 files totalled around 9MB at "5% redundancy" - not quite sure what that means - which isn't much of an overhead for a some extra data security... I think, though I've not tried, that it is integrated into KDE4 too for a little bit of personal file protection.

The interesting thing about par2 is that it comes from an age when bandwidth was limited. If you downloaded a large file and it was corrupt, rather than have to download it again, you simply downloaded the (much smaller) par2 file that had the power to fix your download.

This got me thinking. Is there then any scope for archives to share par2 files with each other? (Do they already?) We cannot exchange confidential data but perhaps we could share the par2 files, a little like a pseudo-mini-LOCKSS?

All that said, I'm not quite sure we will use parchive here, though it'd be pretty easy to create the par2 files on ingest. In theory our use of ZFS, RAID, etc. should be covering this level of data security for us, but I guess it remains an interesting question - would anything be gained by keeping par2 data alongside our disk images? And, after Dundee, would smaller archives be able to get some of the protection offered by things like ZFS, but in a smaller, lighter way?

Oh, and Happy Summer Solstice!

Carved in Silicon

Just found an article on the BBC site that is of interest - 'Rosetta stone' offers digital lifeline. Some nice pointers to research on the life of CDs and DVDs with numbers to use at presentations and it is comforting to read that what we're trying to do Just Aint Easy(tm).

I rather like this too:

"...the digital data archivists' arch enemy: magnetic polarity"

(I added the bold!)

Does that make digital archivists like the X-Men ? ;-)

Standing on the shoulders of Giants?

Just attended the Repositories and Preservation Programme meeting in Aston Birmingham I would really recommend the talk The Institutional Perspective - How can institutions most effectively exploit work in the Repositories and Preservation field? given by Jeff Haywood- University of Edinburgh.

I would like to think this may kickstart a process to find methods by which current projects could more easily use and build on the outputs of previous projects and create a framework to more easily exchange code and ideas.

Jeff's talk was given even more currency as in the afternoon session Rachel Heery give a presentation (its on slideshare) in Repositories Roadmap Session launching her just published Digital Repositories Roadmap Review: towards a vision for research and learning in 2013

The question however remains: by then will Standing on the shoulders of Giants still be a distant concept?

The best introduction to digital preservation ever?

Recently I've been involved in organising a series of 'digital preservation roadshows' for archivists in the UK. The series is aimed at archivists who have had little chance to look at digital preservation issues; the idea is to provide an introduction and some practical, inexpensive, tips and tools that will help people make a start. We've had a lot of positive feedback from the first roadshow (Gloucester, April 29th), though there were calls for a little more easing into the topic and its terminology that we'll need to take on board for the next event (York, June 26th). I wonder whether our delegates might have appreciated this video, produced by the Digital Preservation Europe project. If it's not the *best* introduction to digital preservation I've seen, it's most definitely the funniest. It made me laugh anyway :-) .