{"id":507,"date":"2016-06-14T16:33:32","date_gmt":"2016-06-14T15:33:32","guid":{"rendered":"http:\/\/blogs.kent.ac.uk\/standupcomedyarchive\/?p=507"},"modified":"2016-06-20T08:28:21","modified_gmt":"2016-06-20T07:28:21","slug":"adventures-in-audiovisual-digitisation-part-3","status":"publish","type":"post","link":"https:\/\/blogs.kent.ac.uk\/standupcomedyarchive\/adventures-in-audiovisual-digitisation-part-3\/","title":{"rendered":"Adventures in audiovisual digitisation* (part 3)"},"content":{"rendered":"

*Not really digitisation, more digital transfer<\/p>\n

Because many of our depositors (comedians, promotors and producers) have worked on television and radio we have been given copies of their contributions to these programmes as part of their collections<\/a>.\u00a0 Material has been deposited on\u00a0CD (both audio cd and CD-R), and on DVDs.\u00a0This material is usually\u00a0contributor copies that they were given by the broadcaster or production company, although we do have a few\u00a0‘off-air’ recordings. We’ve also\u00a0received published material, such as recordings of specific shows, tours, or compilations the\u00a0depositor has\u00a0appeared on, including in cassette,\u00a0audio CD and DVD formats.<\/p>\n

In this post I will focus on how we are capturing audio and video material deposited\u00a0on CD and DVD, which Richard Wright nicely describes as \u2018digital content not in files\u2019 (page 9<\/a>). ‘Digital content not in files’\u00a0refers to\u00a0digital recordings which require specific technology and workflows to move the sound\/images from their\u00a0dedicated physical carriers (such as DAT, minidisc, and DV formats, as well as material held on optical media, such as audio CDs, CD-R and DVDs) into digital files (page 3<\/a>).<\/p>\n

\"CD<\/a>

CD from the Mark Thomas Collection of a recording from the Sheffield leg of his 2009 ‘It’s the Stupid Economy’ tour<\/p><\/div>\n

Whilst previously optical media was seen as a preservation medium and storage solution, it is now recognized that optical discs are an ‘at-risk’ format (see\u00a0‘An Introduction to Optical Media Presevation’<\/a> by Alex Duryee’) and so we have been transferring any material of high priority deposited on optical media (mostly that which is unpublished on re-writable discs)\u00a0to a digital file.<\/p>\n

Our approach to this material has varied depending on the format.\u00a0 For material on audio CDs and CD-R we have viewed the physical format as a file carrier,\u00a0as a way to share and transport\u00a0audio files, and we\u00a0view the content on the disc as the important thing to capture (rather than the structure on the disc).\u00a0 However, for DVDs which are more structured (often with a menu)\u00a0we have created a disc image, which we can then mount in tools such as VLC.<\/p>\n

Audio CDs (Compact Disc Digital Audio \/ CD DA)<\/strong><\/p>\n

Audio CDs hold data in the Compact Disc Digital Audio\u00a0(CD DA) format. Data is written\u00a0in the pulse-code modulation stream (PCM), at\u00a0two channel, 16 bit, and 44.1kHz. When an audio CD is placed in your disc drive the operating system will interpret the data into different files (tracks) with the extension .cda.<\/p>\n

After consideration we decided not to extract audio from audio CDs using a disc imaging workflow, but to extract the data\u00a0and save as\u00a0a WAVE file.\u00a0We made this decision based on a number of factors.<\/p>\n

    \n
  1. Firstly,\u00a0it was the audio data itself which was important to us, rather than the structure of the disc.<\/li>\n
  2. Secondly, because\u00a0the discs we had were uncomplicated; many of the audio cds contained\u00a0only two .cda files (one of which was often a radio tone\/test track) or were\u00a0collections of edited tracks from live shows put onto a CD (but not published). Note that we prioritised material deposited on ‘unpublished’ (often re-writable)\u00a0CDs and DVDs; we have not transferred any\u00a0material deposited which\u00a0has been\u00a0published and is on mass replicated discs.<\/li>\n
  3. I think it would also be honest to say that, thirdly, disc imaging audio CDs seemed rather complicated and unnecessary for\u00a0a relatively small number of discs within our collection.\u00a0 I’m slightly ashamed to say that this goes against the guidance provided by avpreserve<\/a>, the open preservation foundation<\/a>, and the DPC\/British Library<\/a>, and I would gladly be corrected if the digital preservation and archiving community thinks we should change our workflow! I would also be interested to hear from other small archives who are undertaking this sort of work, and whether they have disc imaged their CDs or taken a similar route to us.<\/li>\n<\/ol>\n

    Instead of disc imaging\u00a0we extracted audio data using Adobe Audition (a tool we were using for digitising our sound cassettes and MiniDiscs) and\u00a0set the read speed to be low in order to provide as accurate results as possible. The data was originally\u00a0written to the disc as PCM 16 bit\/44.1kHz so we extracted the data as\u00a0this and used the WAVE (.wav) wrapper. The structure of the audio CD disc was maintained using filenames (numbered sequentially by track on the disc) and through metadata which we embedded in BWF format (using the BWF MetaEdit tool<\/a>).<\/p>\n

    We have also received CD data discs containing mp3 files. Although mp3 is not an archival format the sound files are already compressed and saving them as wav files will only increase the file size, but not the quality of the file. MP3 is a format widely used it is unlikely to become obsolete in the immediate future and so poses no preservation risk. We have also been capturing MP3s through audio editing software, either Adobe Audition or Audacity. We are exporting through software, rather than copying straight from the disc, as the software you use will have an error correction element and help prevent any errors during the export\/copy.<\/p>\n

    DVDs<\/strong><\/p>\n

    With rewritable media accessioned into the British Stand-Up Comedy Archive collections (such as hard drives, floppy drives), or media which has inbuilt menu functionality (i.e. DVDs), we thought that here it was important to create a disc image, a sector-by-sector copy, as part of the process of digitally preserving the original accession. Our aim was to:<\/p>\n