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Steve House May 25th, 2005 12:05 PM

Preparing DV Tape for First Use & Storage of Recorded Tape
 
Back in the old analog videotape days and also with reel-to-reel audio tapes during my stint in radio broadcasting it was standard practice to cycle a new tape by fast forwarding to the end and then rewinding it just before use to insure a smooth tape pack and uniform tension. I haven't seen anything suggesting this with digital but it intuitively seems like a good idea to me. What are other's thoughts on this - anyone do it and do you think it may help minimize problems such as sparklies and drop-outs?

After recording, tapes were always stored tails-out and rewound just before playback. Does anyone still follow this practice with DV or is it no longer considered essential since print-through isn't an issue in digital? Again, thinking the smooth tape pack and uniform tension from a fresh rewind might help reduce problems with capturing, etc.

Similarly, in the old days one would record blue screen the length of a fresh videotape before use and often pre-stripe timecode as well, especially when it was to be the target tape for assemble edits. I've seen a couple of references to "blacking" a DV tape and pre-recording code before shooting but haven't seen any definitive information to show this is a standard practice. Do you do it or not and why?

What are currently recommended practices in these regards?

Glenn Chan May 25th, 2005 02:12 PM

The BBC has online training articles. One of them for the VX2000 says to avoid timecode breaks. It mentions that if you black the tapes beforehand, you will have continuous timecode over the entire tape and thus you can never get timecode breaks (at the expense of time and equipment wear).
Considering many cameras have an end search function, you should try to avoid TC breaks in the field. In post, many editing systems can now capture over timecode breaks. Or if you know TC breaks exist, dub the tape first and it will have continuous TC if you do it right.

Uniform tension: Don't know, but it might help because DV still records magnetic signals onto the tape like analog formats. frequencies are much higher though.

Marco Wagner May 25th, 2005 02:14 PM

This was a question I had a few weeks back and have researched in great deal now. From what I have seen and been told here is probably the best method. If I am wrong, or somone has a better method, post it and forgive me.

1. There really is no point in striping or blacking out a DV tape as the timecode get's overwritten anyway from what I have seen and been told. Just extra wear on your heads.

2. It has been recommended that you forward a new DV tape to the end, then rewind it. Then, before an actual scene or shot, roll (record) between 15 seconds to a minute.

3. Always put the tape back into the tape case right away when it's not in the transport.

4. Stick with the same brand tapes. DV tapes use 2 dif. lubes, dry and wet. Mix the two and you can have cement on your heads. Stick with one brand and model DV tape.

5. If you film in extreme weather, like here in AZ 115 degrees is not uncommon 3 months out of the year, wait until you get back indoors to rewind your tapes after a shoot. I did some shooting in the desert a while back, 110 degrees. I made the mistake of rewinding the tape then and there on an old 8mm. It was a new tape, but the heat softened it quite a bit. It had a lot of issues on playback. Another tape, not rewound outside, from the same batch worked great.

6. Tap the tape on your forehead 3 times before putting into the transport. Ok not really...

I use a DV Winder to pack my tapes. Some will argue against this saying that the winder can break or stretch tape. Solution is to use half dead batteries in the winder so it winds slower. My winder stops pretty smoothly and i have yet to have any issues. It still winds the whole tape in like 3-4 mins vs 2 mins on fresh batteries.


After doing all this each time I have noticed a huge drop in dropouts, pops, snaps, frame drops, etc. Hope this helps.

Robert Martens June 3rd, 2005 12:37 AM

I've been curious about this stuff myself, and have asked about it before (posted a comment in this thread), but would like to address something:

Quote:

Originally Posted by Marco Wagner
There really is no point in striping or blacking out a DV tape as the timecode get's overwritten anyway from what I have seen and been told. Just extra wear on your heads.

It may get overwritten, technically speaking, but (at least in the case of the VX2000, which I've used to try this out before) the numbers remain the same. With a striped tape, the camera will write brand new timecode, but it'll match up with the existing, and keep counting the same way the old code did; you can start recording at any point on the entire tape, the code won't break. You'd never know it was "overwritten" just by looking at it. Conversely, with blank tape, breaks are easier to create; unless you start recording at a point on the tape that already has timecode, the camera (this camera, anyway, I'm sure others are different) will start over, from 00:00:00:00. That won't happen if the tape's been striped. And I believe that's the idea. Not "the timecode will stay there forever", but "I won't have to spend time rewinding and fast forwarding to find existing code on a tape I just inserted".

Of course, it's easy enough to just leave yourself a little tail at the end of a shot, so you have a place to start, and it would be plain stupid to simply start recording on a tape without looking at it first (you'll either record over footage you want to keep, or leave too large an empty space on the tape between shots, giving yourself less usable tape real estate), but still--it just seems dangerous. That's me, though, I guess it's no big deal for some people.


I would like to know, though, just how you get bars and tone on the tape if you don't prepare them beforehand. Everybody says that it's only professional to have at least proper SMPTE bars at the head of the tape, if not a chip chart (though I don't understand why. The bars aren't passing through the camera's optics, so they can't be very useful for matching shots, and as far as adjusting your equipment goes, well, why would you have to do that for every new project you work on? You adjust your video and audio monitors when you set them up, then leave them like that, don't you?), but if you're not supposed to do anything to the tapes before they go into the camera, how do you record the patterns?

Likewise, they say even the best decks can't cue up to the exact beginning of a tape, so you should leave room, say maybe a minute to be on the safe side. Shouldn't you have that done already by the time you're on the set, so you don't have to redo it all every time you change tapes?

Steve House June 3rd, 2005 09:17 AM

Quote:

Originally Posted by Robert Martens
I've been curious about this stuff myself, and have asked about it before (posted a comment in this thread), but would like to address something:



... Everybody says that it's only professional to have at least proper SMPTE bars at the head of the tape, if not a chip chart (though I don't understand why. The bars aren't passing through the camera's optics, so they can't be very useful for matching shots, and as far as adjusting your equipment goes, well, why would you have to do that for every new project you work on? You adjust your video and audio monitors when you set them up, then leave them like that, don't you?), but if you're not supposed to do anything to the tapes before they go into the camera, how do you record the patterns?

Likewise, they say even the best decks can't cue up to the exact beginning of a tape, so you should leave room, say maybe a minute to be on the safe side. Shouldn't you have that done already by the time you're on the set, so you don't have to redo it all every time you change tapes?

Don't know what the bars would do at the head of each tape for the camera raw footage but tone would help normalize the levels of audio recorded at different times being edited together. Other than that, bars and tone at the head of final output distribution tapes would be useful and most broadcasters require it. But for DV camera original that's purely a source for editing it does seem a bit redundent.

Meryem Ersoz June 3rd, 2005 10:27 AM

Quote:

Originally Posted by Steve House
Back in the old analog videotape days and also with reel-to-reel audio tapes during my stint in radio broadcasting it was standard practice to cycle a new tape by fast forwarding to the end and then rewinding it just before use to insure a smooth tape pack and uniform tension. I haven't seen anything suggesting this with digital but it intuitively seems like a good idea to me. What are other's thoughts on this - anyone do it and do you think it may help minimize problems such as sparklies and drop-outs?

After recording, tapes were always stored tails-out and rewound just before playback. Does anyone still follow this practice with DV or is it no longer considered essential since print-through isn't an issue in digital? Again, thinking the smooth tape pack and uniform tension from a fresh rewind might help reduce problems with capturing, etc.

Similarly, in the old days one would record blue screen the length of a fresh videotape before use and often pre-stripe timecode as well, especially when it was to be the target tape for assemble edits. I've seen a couple of references to "blacking" a DV tape and pre-recording code before shooting but haven't seen any definitive information to show this is a standard practice. Do you do it or not and why?

What are currently recommended practices in these regards?

These procedures were exactly what I was told to do at an HDV seminar which I attended. The guy delivering the info was remarkably well-informed and precise with everything he did. He ran a film transfer house, and this is how he advised us to manage our video materials for maximum preservation of data. I would say, what was good then is probably still good now.

I almost always stripe tapes (okay, unless I run out of striped tapes and need a shot in an emergency). I rarely have capture problems with a striped tape, but with an unstriped tape, FCP seems to have a greater number of difficulties finding timecode marks. This problem can be overcome fairly easily, but it can be time-consuming, and if you are batch capturing, it can also override previous captures, replacing an already-captured shot with the new one, which is also time-consuming and a pain to fix. Striping seems worth it to me, based on personal experience, not research.

(I stripe on my cheaper camera which I use as a deck, saving wear and tear on the heads of the more expensive camera, unless I'm in a rush, in which case I may stripe using both cameras, which expedites the process....)

Glenn Chan June 3rd, 2005 12:56 PM

If you do your own shooting I would not black/stripe your tapes. Just avoid them when you shoot.
A- Never replay your material. There may be good reasons to replay your material (i.e. check to see if sound and video recorded right). If you do...
B- Use the end search feature of your camera. If it doesn't have it...
C- Shoot extra material onto the end of shots. After reviewing footage, simply cue things back into an area with timecode. It should pick up and not reset to 00:00:00;00. (see Robert's post)

If you do manage to get timecode breaks, dub the tape onto a new one via firewire/IEEE1394. With consumer equipment, the record deck/camcorder should generate its own timecode and give continuous timecode. Work off the dub, which is the exact same quality.

Quote:

I would like to know, though, just how you get bars and tone on the tape if you don't prepare them beforehand. Everybody says that it's only professional to have at least proper SMPTE bars at the head of the tape, if not a chip chart (though I don't understand why. The bars aren't passing through the camera's optics, so they can't be very useful for matching shots, and as far as adjusting your equipment goes, well, why would you have to do that for every new project you work on? You adjust your video and audio monitors when you set them up, then leave them like that, don't you?), but if you're not supposed to do anything to the tapes before they go into the camera, how do you record the patterns?
Some of the professional cameras can generate color bars (just the 6 color bars, which isn't the full pattern). At the same time, an audio mixer can feed tone into the camera, which gives the tone part.

If you use firewire/IEEE1394 transfer all the way through, then bars and tone is kind of pointless. If sending your tape to a broadcaster, your master tape does need bars and tone.
There are some systems out there that are not all digital. DVCPRO is like DV, except much of the older equipment did not have IEEE1394 ports. So you have your audio being handled in the analog domain, and this can be mis-adjusted via the audio input settings on your editing system.

If you are working with analog, bars and tone can be useful since there can be different types of inputs coming in. They all have different levels... for example: (audio) professional line level (+4dbu) and consumer line level (-10dbV) [which differ by 11.78dB].


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