practice sorce file degradation

[tintinibar]

I've used the same practice source file, which is a DVAVI from my camcorder that uses mninDV cassettes, about 10 times. I have only run the original cassette a few times. It's a 3 minute video clip of my son and I was troubleshooting a problem that I had and have since corrected it. How can you compare the degradation of a source file that has been used never, 10 times, 100 times, etc? Even compared to the original cassete data, I know that cassettes wear out, but can someone compare it to something in life that would give someone without all the techcnical knowledge a basis for someone who plans on doing a lot of premiere, after effects, chroma, etc editing with the same ssource file to know they will have quality loss? Also, if you were to make, say 100 copies of a DVAVI file from cassette, is it harmless to make all 100 copies from the first DVAVI, or all 100 from the cassette directly, or is there an in between?

[mustardman]

I'm afraid I don't really understand your question, but here are a few tips.

Every time you do an edit (eg:fade) & recompress you loose quality - most people will muck around with several edits to get the look they want, and then combine all the "edits" into one processing file and work the original.

ie: To find out what...
orig -> motion stabilise -> A
A -> fade -> B
B -> colour correct -> C
C -> black border -> D

Then, once all parameters are defined, then
orig -> motion stabilise, fade, colour correct, black border -> A

Direct cuts will not alter the quality, unless you are using a crappy editor or a temporal based encoding method (eg: MPEG). DV, MJPEG, HuffYUV are all examples of "non-temporal" encoders.

Try not to dub tape -> tape multiple times as although the signal is digital, the tape will still degrade. Capture the tape (tape -> AVI) and then use the computer to go AVI -> tape as many times as you like. Hard disks are considerably more robust than video tape.

[theReal]

is it harmless to make all 100 copies from the first DVAVI, or all 100 from the cassette directly

It is absolutely harmless to make 100 copies from the DVAVI on HD (as long as your HD doesn't break - which it shouldn't before you've done several thousand copies).

As mustardman said before - a tape wears out much faster than a HD, so after 100 copies you might already have damaged the tape which would lead to serious errors or total read failure.