8mm Movie Film, Super 8 Film, and 16mm Movie Film
to Digital Video
Tutorial
Archiving Concepts
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By: Bruce Mayfield |
One of the primary purposes our customers use our service for - though most of them aren't consciously aware of it - is to archive their family memories.
Strictly speaking, an archive is a long term repository for stored memories or information. An archive is useful only if it meets three criteria:
- It's accessible -- to you and your Heirs -- using consumer available technology.
- It's safe for -- at least 15 to 20 years -- one generation.
- It's equivalent -- and does not compromise each, entire frame of your original movie film.
In the past, archives were made up of media that was "human readable" - primarily because there were no machines around able to do data interpretation. Texts and tomes were the heart of an archive, later pictures and photographs.
It was a natural step - for the sake of saving space - to utilize other forms of storage. Microfiche photography served to vastly reduce the physical size of many archives, and because microfiche readers were so easy to make it kept accessibility high.
Now there is so much information to store that even photographic reduction isn't enough. Digital storage is increasingly attractive both because of the very small area digital media takes up compared to the information it stores but also because so much of that information can be stored on-line and immediately accessible via a myriad of indexing techniques.
| Dirty Little Trade Secret |
| Nothing can be considered an archive if half the information is gone, and the other half distorted, even slightly. No DVD can qualify as an archive medium - the compression method used throws away too much information and the artifacts can distort the final image. Don't let the "transfer mills" claim that DVDs are anything other than a convenient viewing media. |
An archive must survive technology shifts. The problem facing archivists today is making sure that the digital media they choose to use -- today -- can be accessed tomorrow, in the future. Media for storing digital information change so often that one common media this year can be a vague memory (pardon the pun) next year.
For example, now that we know DVD-R/+R technology only last for 2 to 5 years, it is now an act of insanity to use DVDs for archiving. DVD technology itself, is being replaced with Blu-Ray technology. Hard Drive technology is being replace with Flash Drive and Flash Drive Array technology. Basic "wired" interfaces are becoming "wireless" -- like your mouse, keyboard, WIFI card, LAN nic, and, etc.
Digital archive media has to be tough. You can not expect a hard drive -- say nothing of a series of hard drives (RAID) to be working in 10 years. Archivists are always watching the market for media that can sit on a shelf without fear of time itself compromising the media or the data. We have learned some hard lessons in the past. Triacetate movie film was once thought to be the end-all archiving format for movies - but vinegar syndrome now threatens the world's collection of movie memories, including your home movies. CDs were once thought to have a century of shelf life in them, but it later turned out that the aluminum sheet would sometimes start to separate from the plastic shell, making it unreadable, and there is even a fungus that loves the emulsion of CD-Rs -- which is organic. DVD-/+R only last 2 to 5 years. Faster "video certified" hard drives -- which most people use to "achieve" their video -- generate more friction and heat and "die" quicker that "normal" hard drives. Older flash drives had "serial" data access paths and if the access path failed "anywhere", then the whole drive failed.
Digital Format is more important than Digital Medium. Until the perfect archiving media comes along, archivists must constantly focus on the fact that they are archiving the information -- the data, not the media. Whenever feasible, digital information is duplicated exactly onto new media. Extreme care must be taken when replacing one medium for another -- without replacing one format to another. .Any format that eliminates data in order to save space is not suitable for archiving. The terminology for this trade-off -- data loss for extra space -- is a "lossy" format. MPEG2, MPEG4, and AVCHD - the formats "packed" onto a DVD, are profoundly "lossy" formats.
For example, if you copy video from a MiniDV to a DVD; and, then copy that DVD back to yet another MiniDV. When you compare the video on the two MiniDVs, you will see the video on the MiniDV made from the DVD has many tiny, monochromatic digital blocks -- called "artifacts". These artifact are a result of lost visual data which is lost -- in the lossy format -- when making the DVD.
Anytime you copy a "lossy" format to a "less lossy" or "non-lossy" format, the CODEC (COder DECoder) simply "plugs" the lost data with a little digital "blob" -- usually a square -- of monochrome video. This is true even within the same format -- if the compression ratios are different. An example of this is DVD to Blu-ray. If you copy a DVD (MEPG2 format) to Blu-Ray (which is also MEPG2 format -- only a bigger footprint per frame), you will get lots of digital artifacts. This is because the extra space in the larger format frame - the larger footprint -- has to be filled with something -- digital "blobs" of video. This technology is, by the way, is getting pretty good.
The new generation of "up-scaling" technology -- built into ALL DVD / Blu-ray players -- designed for HDTV -- is so good, that DVDs designed for old "TV sets" actually look better on an HDTV screen that they every did on older TV sets. For this reason, the public is finding it hard to justify paying the higher prices for Blu-ray movies. It is also for this reason, that it is better (in my opinion) to keep your OLD DVDs and play them in NEW DVD players -- with "up-scaling" hardware -- rather than buy all new movies in Blu-ray format.
The best results in changing from one format to another -- even with a "lightly lossy format" -- is realized when the format of origin is made up of "full frames" of video -- not partial frames of video. When a "full frame" of data is expanded, simpler "line doubling" and "dot doubling" -- used by "up-scaling" techniques can be used to expand the image to fill up the desired screen or format space -- with relatively few artifacts.
This brings us to the next very important subject -- matching and mismatching original visual images with an appropriate video format. Let us look at all this information in the context of an 8mm movie film to video transfer.
