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 "Q9: 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.