Hi Joel:
My two cents here as I do this for a living....
I would be hard pressed to send your one-of-a-kind tapes to any chain.
I've heard of one horror story after another.
For all the reasons you mention below and more, I would only go to DVD
as a second/reference media in conjunction with the master file. Ripping
files from DVD is a poor substitute for going directly to a higher
quality file-based format in the first place. File based format is the
direction everything is headed. You want multiple copies of the files
stored in different physical locations. I don't like cloud or other
services, I like to be in control of my own destiny. If you have
checksums made of the files while on the original capture drive, and
move the checksums with the data, you insure no data corruption. Then
run the checksums on a regular basis (every 6-8 months) on each copy
drive to insure the drives still hold the data without any data
degradation.
In analog video, there is no "metadata" that holds the original date and
time, so there is no way to capture this as part of the file.
Insure the analog video is digitized properly and with the right
equipment. Multiple options for playback decks allows one to see which
tapes best play back in the best deck. The analog video signal should be
properly set up and adjusted (using scopes and processing amplifiers)
and properly processed with the right time base correction to insure the
analog signal is as stable and clean as possible before you digitize.
Picture instability, color noise, etc is "baked" into the digital
version during digitization and it is very hard to correct for after you
have digitized. Choosing the right codec and compression levels for your
needs is key. The less compression, the more you can do with the content
and the better the content will migrate to new formats in the future.
Some camps will say uprezz now. Some like myself, say to stay as close
to the original format as possible - the same image ratio high by wide
as possible, holding the essence of the original analog format
(interlaced, not progressive and at 29.97pfs). Color sampling rates are
important. You want as much color information as practical (based on the
original format). Better to have the highest quality standard-def
interlaced file that you can afford to store now. There will be both
hardware and software solutions down the road that will do a much better
job at uprezzing and de-interlacing than can be done today.
There has been recent discussion about this on the AMIA list-serve
recently. Below is the answer from Jim Linder who really knows his
stuff, when your same question was asked. Hopefully he does not mind
that I quoted him.
Good luck,
John Schroth
MTS
"Fortunately in analog encoded (as in NTSC) there is a good answer if a
bit technical. I am going to try to give a short, coherent, and
understandable answer - but there is a great deal of in depth technical
information on this subject available elsewhere and if others want to
discuss it off list I am happy to.
We need to go back a bit and look at the development of NTSC and how the
color information was added or encoded into the black and white picture.
The standard adopted by the FCC mandated that those who had a black and
white television would not have to throw out their old tv in order to
get color. Color information had to be encoded into the black and white
signal - the black and white televisions would basically not see or
ignore the encoded information, and color sets would see what is called
"burst" which is essentially a signal to turn on the color decoding
circuitry and to decode the color information and apply it to the
signal. This burst signal is also called subcarrier and is of a specific
frequency. The color information was encoded based on the phase
relationship of the subcarrier during the period of time of the line of
active black and white information. Remember this is all analog and
based on time / frequency and amplitude of a signal. The phase of the
subcarrier signal contains the color information.
If you think of this phase relationship you realize that it takes a
certain amount of time to change from one phase relationship to another
- so color changes that are "nearby" or close to the previous can be
done in plenty of time, but ones that are 180 degrees out of phase
actually take a bit more time. During the time that the phase is
changing, you actually do not know what the color is at all. Normally
and in analog this is not an issue because your eye cant see such a
small part of the line, except in extreme circumstances such as when
someone is wearing a herringbone jacket or very intricate patterns with
different colors. When this happens we actually see noise or moire
patterns because the decoding in the set can not change fast enough and
so you get visual artifacts.
So, the practical limit to the horizontal resolution in digitizing an
encoded SD signal (like NTSC or PAL) relates to the burst frequency and
the time available. If you sample higher then the frequency of the
information that it was encoded in, you are generating noise and
visually the signal can actually look worse. A great deal of
experimentation was done to determine what actually is optimal and
certain digitizations systems that were built actually considered this
so that there was no "oversampling" and thus the reduction of quality
and the adding of chroma noise in the picture.
There is another factor and that has to do with the chroma decoding of
the encoded signal. There are several kinds and some are better with
certain signals with others. There are comb filters that remove specific
frequencies in order to present a cleaner lower noise signal and
adaptive comb and other filter types that are all designed to reduce
noise and artifacts.
So you do not digitize in the highest resolution possible - you digitize
at the optimal resolution and with the optimal chroma decoding to get
the cleanest and most accurate representation of the original analog
signal. Fortunately this technology has been available for some time and
a great deal of video preserved has used this technology and is now
happily in files."
On 12/11/2016 9:37 PM, Joel Bresler wrote:
> Dear friends:
>
>
>
> I would like to digitize some camcorder footage. A few questions for anyone who has tackled a similar project.
>
>
>
> First, there are plenty of services (Costco, etc.) which will digitize tapes onto DVDrs. I am wondering in this age of increasingly cheap storage if it makes more sense to go from tapes directly to digital files instead? (Avoids any quality issues going to DVD first and then ripping to digital; avoids issues with suitability of DVDrs for archival storage; renders video in editable, digital form right at the start.) Are there any suggested services that take this approach?
>
>
>
> Second, any suggested quality level for the video? Is there any need to preserve it at a higher resolution than the original?
>
> Third, suggested ways of storing the digitized video? (RAID array? Backed up on Amazon Web Services?)
>
> And last, is there any way to capture date and time metadata on the transferred video? WITHOUT showing it continually on screen as the video plays?
>
>
>
> Thanks in advance for your insights!
>
> Regards,
>
>
>
> Joel
>
>
>
>
>
> Joel Bresler, Publisher
>
> www.sephardicmusic.org
>
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>
> Lexington, MA 02420
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