Preservation Formats

The issue of recording formats

Starting with the first tape BAVC transferred, the choice of recording formats has been controversial. For example, BAVC learned that the Minnesota Historical Society, with advice from technicians at 3M, chose S-VHS as the recording format. The stock is inexpensive, the players are plentiful, and the format is stable. The S-Video standard allows for better signal integrity relative to a composite transfer.

Since the center opened, debates have continued about the best preservation format. Granted, it would be difficult to tout S-VHS as an archival format equal to Betacam SP or Digital Betacam. However, the preferred format for a technician in the independent media field may be different from those recommended by an archivist or a conservator.

The technician's question, first and foremost, is often: "Do you want to see your tape again?" A technician is concerned about the shelf life of a tape format and its ability to reproduce the image and sound of the original,. Many of BAVC's clients do not have outside funding for the project , and some are not interested in issues of conservation. At BAVC, our focus was on preserving the original tape and accepting the reality that there is no ideal format. BAVC explains options to the client, Who then makes a decision about formats.

In my opinion there are recording formats that should be avoided and others that are best for transferring obsolete tape formats.

Preferred preservation formats

The preferred formats to transfer to are SVHS, Betacam SP, Digital Betacam and D1.

? S-VHS - A composite analog format that is cheap, easy to find and provides reasonable quality. A valid choice for a budget transfer.

? Betacam SP - A component analog format that has become the standard in broadcast production. The video signal is actually 3 discrete signals, and these signals are even recorded separately on the tape. While Betacam SP offers the best recording quality in an analog format, it has the reputation of having more dropout than U-matic and one inch. Also, the less expensive UVW Betacam SP tape machines are much less robust than the broadcast models, and have more problems.

? Digital Betacam - The preferred recording format at BAVC is a controversial choice. Digital Betacam offers 4:2:2 component recording and is a clear market leader in the video production community. But Digital Betacam is also digital recording and has 2:1 DCT compression. While there are many arguments to "stay analog" in remastering, the reality is video production has not been all-analog in twenty years, since digital time base correctors began to be widely used. The TBC, an essential tool for recording a viewable image from 1/2" open reel, is a digital box that converts analog signals to digital and digital signals to analog.. If you use a TBC to transfer, you've already moved from analog to digital. The issue of compression is much stickier; the question really is whether DCT compression, as it is implemented on Digital Betacam, is transparent enough for the purposes of video remastering. Given the market dominance of Digital Betacam, the viewable quality of the image and its cost-efficiency, the DCT compression of Digital Betacam seems acceptable, especially considering the relative low technical quality of the original formats being transferred.

? D1 - An uncompressed digital component format. BAVC was not able to justify the expense.

Formats not recommended

In my opinion, there is a high risk when transferring tapes from obsolete formats to 8mm/Hi-8, MII, DCT, DV/Digital 8, Betacam SX or DVD.

? 8mm/ Hi-8 - These formats employ tiny tapes; engineers hate to work on such small scale machines. Hi-8 offers the same image quality as S-VHS but more dropout. It is a format that has been superseded by the small digital formats; however, there are still plenty of tape machines out there. In the future, 8mm/Hi-8 will pose challenges for preservation.

? MII - A Panasonic format that is equal Betacam SP's equal in everyway except popularity. MII tape machines are hard to find.

? DCT - Ampex's digital component format. Ahead of its time. Long gone.

? DV/Digital 8 - Both formats are designed to be cost effective digital formats. Compression is reasonable for field acquisition (5:1 DCT), formats are 4:1:1 component, with 2 chroma (1 B-Y signal, 1 R-Y) signals for 4 Y (luma) signals. Tapes and tape paths are tiny, making the machines difficult to work on and probably less reliable than the larger formats. DVCPRO 50 offers better quality but is stillvery small.

? Betacam SX - A compressed digital 4:2:0 component format that is strictly for field acquisition.

? DVD - This digital format is designed for distribution, not for remastering.

Transferring tapes to one inch, U-matic, D3/D5, D2 or Digital S is not recommended, although the risk is somewhat less than transfers to the formats listed above.
? One inch and 3/4" U-matic - Should be considered an obsolete formats for remastering. Reliable technicians, machines and parts are increasingly difficult to locate.

? D3/D5 - Panasonic's answer to Sony's D2 and D1. Great quality, But machines are difficult to locate.

? D2 - An uncompressed composite digital format that has been superseded in the marketplace by a compressed component format, Digital Betacam.

? Digital S - A digital format with the form factor of VHS and the specs of Digital Betacam. An attractive idea with a small market share.