Studies FY2008
The themes of studies FY2008 are as follows:
(1) Study on digitization of analog audio-visual materials
A comparative study on specifications to digitize analog audio-visual materials for each purpose (for preservation and for distribution) was conducted.
The NDL conducted trial digitization of its holdings of analog audio-visual materials and compared the sound and image quality by listening to or viewing each digital file.
Audio materials
The target materials are the following:
- Cassette tapes
- Open reels
Table 1 shows the conditions for digitizing audio materials for preservation and for distribution.
| Table 1: Conditions for digitizing audio materials | ||||
|---|---|---|---|---|
| Usage | File Format | Sampling Rate | Bit Depth | Bit Rate |
| Files for preservation | WAV(.wav) | 48kHz | 16bit | - |
| 96kHz | 24bit | - | ||
| 192kHz | 24bit | - | ||
| AIFF(.aif) | 48kHz | 16bit | - | |
| 96kHz | 24bit | - | ||
| 192kHz | 24bit | - | ||
| Files for distribution | MP3(.mp3) | - | - | 128kbps |
| - | - | 320kbps | ||
| WMA(.wma) | - | - | 128kbps | |
Visual materials
The target materials are the following:
- VHS (Video Home System)
- Betamax videocassettes
- U-matic videocassettes
- LD (Laser Disc)
- VHD (Video High Density Disc)
- Motion picture films (8mm/16mm)
Table 2 shows the conditions for digitizing visual materials for preservation and for distribution.
| Table 2: Conditions for digitizing visual materials | |||||
|---|---|---|---|---|---|
| Usage | File Format | Container | Bit Rate | Rate Control | Audio Codec |
| Files for preservation | MPEG-2 | MPEG-2 PS (.mpg) | 9Mbps | CBR* | LinearPCM |
| 9Mbps | VBR** | ||||
| 50Mbps | VBR | ||||
| MPEG-4 AVC | Matroska (.mkv) | 9Mbps | CBR | ||
| 9Mbps | VBR | ||||
| 50Mbps | VBR | ||||
| Files for distribution | Flash Video On2 VP6 | Flash Video (.flv) | 300kbps | CBR | MP3 |
| MPEG-4 AVC | MPEG-4 AVC (.mp4) | 300kbps | AAC | ||
| Windows Media Video | Windows Media (.wmv) | 300kbps | WMA | ||
*CBR (Constant bit rate)
**VBR (Variable bit rate)
The results of the study showed the difficulty of determining uniformly the most appropriate specifications for all kinds of audio/visual materials and the need to develop a policy on the level of required quality of digital files, considering factors such as physical condition of original materials and cost-effectiveness.
(2) Trial migration of 5.25-inch floppy disks (FDs)
The NDL holds a number of 5.25-inch FDs, which are deteriorating physically over time. Therefore, the NDL conducted migration[*] of data from 5.25-inch FDs to a hard disk on a trial basis.
[*] Migration means to transfer data to a new recording medium or convert data format so as to ensure the long-term accessibility of the data. For details, please see "What is "migration" and "emulation"?" in the FAQ.
The migration was carried out in two stages. First, the data was transferred from 5.25-inch FDs to 3.5-inch FDs with a dedicated data converter, because a data converter reading data directly from 5.25-inch FDs was not easily available and the production of dedicated external FD drivers had already stopped. Next, files transferred to each 3.5-inch FD were converted to one image file and stored in the hard disk.
As a result, about 86% of them were successfully migrated.
The NDL's study on migration of FDs has been under way since FY2006. Please also see Studies FY2006 and Studies FY2007.
Other FY2008 activities
The NDL made a pilot assessment of the Digital Library from the Meiji Era in terms of long-term preservation of digital contents with DRAMBORA (Digital Repository Audit Method Based on Risk Assessment).
DRAMBORA is a toolkit to facilitate internal audit by providing repository administrators with a means to assess their capabilities, identify their weaknesses, and recognize their strengths, jointly developed by the DCC (Digital Curation Centre) and DPE (Digital Preservation Europe).
The NDL translated DRAMBORA ver. 1.0 into Japanese.
For details, please see the news of "DRAMBORA Translated into Japanese" in the DRAMBORA website.