XH-A1 playback issue question. Please Help

[Jay Jelliff]

I have experienced a problem with playback, timecode not counting and sometimes the tapes just goes to a blue screen and stops. I'm using Panasonic tapes. It's happened 3 times, once at the very beginning of the tape and then was played fine after 4 minutes, the second was in the middle of a tape (11 minutes choppy from 13:00-24:00), and the third was the beginning of a tape 00:00-17:00. Two of the occurrences were outdoor filming, the third was an indoor studio interview. After an exhaustive internet search finding almost nothing on causes and correction, I found a youtube video that demonstrates what I am experiencing. At the 47 sec mark of the following video, the poster shows the LCD on the XH-A1 with an example of the video problem.

NEED HELP!! XH-A1 / Mini-DV Tape Problem - YouTube

Is it dirt, misaligned tapes or what? I have run a head cleaning tape after the first occurrence without success.

Any input would be appreciated.

[Colin McDonald]

Do the problems recur consistently (exactly the same place and fault) every time the tapes are played back on the XH-A1?

Have you tried playing back the tapes on another camera, and if so do you get the same results?

Are the tapes you are using all from the same batch?

[Eric Olson]

Originally Posted by Colin McDonald

Are the tapes you are using all from the same batch?

This sounds like either a broken camera or a bad batch of tapes. It is easiest to check the tapes first. Clean the heads and try a 63 minute Sony HDV tape. If the problem goes away, the Panasonic tapes are either defective or counterfeit. Don't use them again as such tapes may damage the camera.

[Jay Jelliff]

The playback problem occurs in the same place on each tape. I have tried the tapes in my other XHA1 and 2 different HV30's. Same problem in the same place on each tape. I buy tapes 100 at a time (20 boxes of 5) and other tapes from the same batch have performed fine. I can also take the same tape, with the problem on it, and fast forward to a blank area of the tape and record/playback fine. I have always used the same Panasonic tapes. As for "a broken camera or bad tapes", yes. Considering those are the only two things involved, it certainly must be one of them. :) I was hoping to isolate the problem before I send in the camera for repair.. Hopefully, someone on here has seen this problem before and tell me what they found to be the cause.

I have run dozens of tapes through this camera and have yet to have it fail. So, 3 tapes out of the MANY I have used doesn't exactly constitute a consistent problem. I just never know when it's going to happen and I worry about shooting irreplaceable footage.

[Colin McDonald]

It sounds like the tapes, but you would only know that for sure if you had a similar problem with the other XH-A1 using another of the batch.

I have a Firestore for really important recordings where continuity on a single camera is critical so that I would have back up in the event of a dropout. It sounds like you have a similar possibility of using another camera connected through FireWire to do a simultaneous tape recording as a backup.

Sorry that's my best suggestion.

[Jay Jelliff]

Thanks, Colin. I guess I'll burn a few tapes from the batch through the other A1 and see if it suffers a similar problem before sending Camera 1 in for repair.

[Noa Put]

Originally Posted by Jay Jelliff

I just never know when it's going to happen and I worry about shooting irreplaceable footage.

The only option for that is to buy a external recorder, my xh-a1 is not being used that much anymore but have used it with a sony hvr-dr60 for about 3 years with no dropouts, I run tape for backup but actually have not got a clue if it records to dv tape without errors as I never had to use them.

Btw, the problem I see in the video looks very probably like a tape issue, I have had a similar experience loosing about 1 hours worth of church footage, I had about a hundred dropouts on a brandnew unused jvc dv63me tape, it happened right after I changed the tape and the camera never gave me any warning during recording, it was very cold and humid that day and warm and dry inside, I filmed with another tape when I got inside the church and changed tapes after about 5 minutes, that second tape got me into trouble. Right after that I bought the Sony recorder, best investment I ever made with that camera.

[Chris Soucy]

This sounds like yet another occurance of the dreaded BSOD (Blue Screen of Death).

Yes, it's possible it's just a fault with that one tape, the only way you can tell is to put it back in the camera, rewind it and then record right to the end and see if the problem reoccurs.

If it plays back fine after the second record, it's a BSOD.

Historically, the most common occurances has been either: when operators have been in a rush to change tapes due to ongoing performances, and not fully seating the tape in it's carrier, causing the tape to mistrack.

There is no warning and no indication things aren't working fine UNTILL it comes time to rewind and play it and, nothing! (This has been the most common documented reason).

Variants of this are newbies being a bit tentative or operators not really paying attention to what they were doing.

It is possible, if occurances become more and more often, that it indicates a pinch roller wear problem or other issue with the deck, but I've never seen a documented instance where that has definitely been fingered as the culprit.

And no, the mistracking that causes a BSOD removes too much data to resurect the I frames, though in most instances the GOP header frames, though currupted, can be seen in the viewfinder during Play/ FF.

Try the tape again and see what happens, then you'll know for sure.


CS

[Noa Put]

That's the first I hear about it, my tape that had the problem recorded and play-backed just fine when I tested it afterwards so it definitely would have been such a "BSOD", interesting. And yes, I was in a hurry to exchange tape at that time :) Though I find it strange this would be the case as I have been doing that for years without an issue, I don't see how you can not fully seat a tape, it just slides in, you close the door and off it goes?

[Jay Jelliff]

Originally Posted by Chris Soucy

This sounds like yet another occurance of the dreaded BSOD (Blue Screen of Death).

the only way you can tell is to put it back in the camera, rewind it and then record right to the end and see if the problem reoccurs.

If it plays back fine after the second record, it's a BSOD.


CS

So, if it is the BSOD, is it the tape or the camera?

[Chris Soucy]

If it's a BSOD, it's neither the tape nor the camera.............it's, er, you.

There is just enough clearance in all the tape transports I've investigated to allow the tape to not fully seat by anything up to 1/2mm.

Doesn't sound like much and isn't, but that's all that is required.

Interestingly, I've attempted to provoke a BSOD by deliberately mis - seating tapes in 3 seperate decks, over and over and over again. Not once has it done it, which means nothing except I simply wasn't doing it right, er, wrong, somehow.

There is another possible theory which I haven't bothered to explore as life's too short, and that is that the spool locks somehow haven't kept the tape tensioned for some reason, and it is that which has allowed the tape to mis - load.

This theory goes down the gurgler when matched to the "quick change" criteria that so many of these instances have in common, but it's a theory.

To reiterate, I've seen not one instance where tapes suffering from BSOD symptoms have had data successfully recovered from them from the original write, so don't get your hopes up.

Oh, and no, re - aligning the heads is not an answer, as, because of the tape mis - tracking during the write, the data WAS NEVER correctly written and simply is not there.


CS

[Chris Soucy]

Originally Posted by Chris Soucy

Oh, and no, re - aligning the heads is not an answer, as, because of the tape mis - tracking during the write, the data WAS NEVER correctly written and simply is not there.

To explain this in slightly more detail, the I frame build and error correction algorithms in HDV cameras are fiendishly clever and mind bogglingly complicated, using both look forward, look backward and numerous other ways to assemble data and correct it for the errors inherant in tape systems.

It has to be an incredibly robust system and can cope with numerous types and degrees of data loss.

HOWEVER, a BSOD error corrupts not only every I frame, but every GOP header frame as well, so that the look forward, look back algorithms simply do not have a "whole" frame anywhere to use as a basis for comparison.

This is way in excess of what the error correction system can fix, so it's "game over".

The GOP header frames still appear during play/ FF because, even though damaged, they were "whole frames" so the undamaged information is displayed, even though unusable for I frame rebuilding.

So, when I say "simply is not there", it's true even though it's not. Everybody got that?

Nope, thought not.


CS

[Chris Soucy]

Noa,

You'd think so, wouldn't you?

just slides in, you close the door and off it goes

Well, on occasions, it simply doesn't.

The worst case I can remember was a guy in Russia who'd shot either 5 or 7 tapes in sequence, all with quick changes.

Of that number, whatever it was, 3 tapes straight, in sequence, were afflicted by BSOD syndrome, total write offs.

It wasn't the tapes, later confirmed to work perfectly after another write/ read cycle.

Here, and on other sites out there, I've seen it happen with every HDV camera, from every manufacturer, and every single tape type.

It just happens, but usually with the "quick change" to the fore.

I've been watching this for the last 6 years at least (ever since HDV went live) and it's been a constant background noise from the start.

Rare, but it keeps happening.

Roll on solid state (and a whole lot of other problems).


CS

[Noa Put]

Eventhough I don't have to deal with it anymore I do find it interesting to hear another possible explanation for what happened that day, back then when I lost 1 hour footage I was able to capture the tape completely but had only short clips from a few frames to a few seconds. I did try to reconstruct what was left but it actually was just unusable, my only luck was I had an iriver on the groom and since that did not record directly to the camera I at least had something intact to work with. The sound on the tape was totally useless. Like I said when I recorded over that tape again it recorded just fine.

I had asked everyone I knew for an explanation and no-one every heared of something like this happening, they also couldn't understand why the camera didn't give any warning, the xh-a1 was only a few months old and all my tapes where only used once and taking out of it's wrapping when I used them. The only thing that came up was the weather condition, it was cold and humid outside and hot and dry inside and since I replaced the tape right after I got into church that sounded as a reason. But when I hear your explanation that sounds more like it.

Next time I have a recording problem I"ll come to you :)

[Jay Jelliff]

Originally Posted by Chris Soucy

If it's a BSOD, it's neither the tape nor the camera.............it's, er, you.


CS

Ok, that made me laugh out loud! I'm still smiling as I type. Thank you for your candor.

Now on to my dispute of that statement. On one of the three problem tapes, the problem occurred in the middle of the tape. The first 13 minutes recorded and played back for capture perfectly. At 13:04 the skipping began and at 24 minutes the skipping stopped and I captured the remainder of the tape without problem.

As I researched this problem on the web and waited for advice on here, I found advice to FF and rewind the tape several times before attempting playback. On another of the problem tapes where the skipping occurred at the beginning, I tried the FF/rewind solution. I FF and rewound the tape 4 times and initiated playback, surprisingly, I was able to play and capture the first 4 minutes of the tape that had the issue without problem. Subsequent attempts to play the tape resulted in the skipping returning.

I have been shooting HDV video with this camera and other AH-A1's for many years and have used literally hundreds of tapes. I have never had any problem and now suddenly I have 3 tapes in a month where the problem is uh, er, ME!?!? All the problem tapes came from the same camera and tapes from the same batch used in other XH-A1's and HV-30's have no problem. You see why I am suspicious that there is a problem with THIS camera??

I await your response.

Thanks