HPX250: Bad frames in recording

B

brynsank

Active member
Anyone having issues with bad frames/encoding glitches/TC breaks when shooting with their HPX250? I don't recall having the issues when the camera was new a year or so ago, but recently I've been getting them on almost every shoot and it's driving me nuts. The TC breaks create all sorts of hassles with exporting - causes failures every time until I find the problem, which is infuriating on long recording like presentations where I typically wouldn't watch the whole thing through before exporting. I've attached an example from a recent shoot. Originally shot at AVC-I 50 29.97p, resized to 720p for the interwebs.AD B-Roll.Still001.jpg
 
I bought mine right when the 250 first came out and it shoots today as well as the day I got it. That frame is crazy wierd.
You may need to ship it the camera back to Panasonic. At least you have the 5 year warranty.
 
Interestingly, it seems that it's getting much worse. That shoot was only about 20 minutes long, but I had about 5 or 6 bad frames... When it started I would only get one bad frame for every few hours of recording.
 
This doesn't look like bad P2 media or unverified P2 data offload. That has a different, distinctive look on the final footage. After 7 months of light-moderate use, I never experienced such. Maybe the AVC-I VLSI chip gone haywire somewhere inside.
 
The only question that matters right now is -- what does the footage look like when played back from the P2 card? Do the glitches show up there? If the footage looks good on the card, then there is nothing wrong with your camera or your card, and it is almost unquestionably a problem of how the footage is being copied to the computer.

So verify the appearance of the footage on the card. If it IS glitched on the card and plays back from the camera (not from the computer, but from the camera) with glitches, then move on to step 2: is it happening on only one card, or all cards? If it's on only one card, and every other card works perfectly, then suspect the card. If all cards have a problem, then the camera is likely at fault.

But if the footage is good on the cards as played back from the camera, then it's the computer that's at fault.
 
It sometimes appear on my NLE monitor ( premiere CS5 ) but i never seen this on the final export. plus if i restart my NLE, it disappear
 
Do you ever see it when you play the original P2 card footage back thru the camera LCD screen? Looks more like a computer hardware or software issue.
 
How interesting - as you suggested Barry I played it back in-camera and it appeared flawless (I just watched it in-camera, not on an external monitor). Now that I think of it, I've been a little suspect of the USB port I'm using from time to time due to some unusual behaviour with other devices. I'm going to try re-importing it through another port and see if that makes any difference.
 
I'm pleased to report that I re-imported through another USB port (PCI-e USB3 card rather than the motherboard port I was using before) and the bad frames are now good. I haven't had time to go through the footage with a fine tooth comb yet to make sure there there are no corrupt frames left, but there were specific timecodes I had taken note of before re-importing, and the corrupt frames at those places are now rectified so I think it's pretty safe to assume that the source of the problem has been identified.
My sincere thanks to you Barry for making the suggestion. I actually received the Return Authorization Form from Panasonic yesterday after a lengthy discussion with one of their techs over the phone - they suggested I send it in for warrantied repair. So I'm very grateful to have been able to identify the problem before sending it off!
 
Also be aware the USB transfer process appears to be very particular. Make sure the 250 is the ONLY device on the hub. Sharing with a disk drive or other device will often hang or corrupt the transfer. A lesson learned from another kind soul here at DVXuser.
 
Typically I copy all P2 content to the hdd and import from there. When editing in CS6 or FCP X, if it imports in all OK, I can format the card. Rarely ever read it directly off the camera unless it's an urgent, time sensitive live scenario or that there's no extra P2 reader to do the job. Reading off the HPX250 adds risk to the data if one's not careful to check for any digital flaw.

This sheds some light to how fragile USB to hdd is and the whole P2 data archival process. Even if you store the verified (MD5 or byte by bye) copied data on the hdd, that too is at risk of some sort of data corruption. Either left on shelf for too long (>1.5 years where fewer lubrication and de-magnetization kick in) or simply regular hdd mechanical servo failure.
 
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Well, to be fair, that has nothing to do with P2: it's the same situation facing every digital media, including CF cards from the Red or DSLRs, or SxS cards, or SDHC/SDXC cards, or even your own computer hard drive backups...
 
Yeah I used to use a P2 card reader until it died - then I just switched to reading off the camera via USB. Takes a little longer, but does the trick for no additional expense. I'm normally not rushed as I usually won't start editing til the next day.

FWIW, my process (when I was getting corrupt files due to the USB issues) was to connect the camera via USB, open P2 Viewer, create a new virtual card on my HDD, then copy from one to the other. The beauty of P2 Viewer (unlike a straight file copy) is that you can view all mounted P2 cards at once and read from them as though they are one unit. The downside is that, as far as I can tell, there is no verification process - unless it is included but not acknowledged during the copy process.
The other day when I ran it through another USB port I used Adobe Prelude because of the option for bit-by-bit verification. The downside to this is that it seems I can only read from one card at a time. Often I have media spanning two cards, so this creates an extra step.

lonewolf, I'm not sure how the failure rate of hard drives speaks to the fragility of the P2 archival process. I have never (and will never) archive my footage on HDD only. That is just foolish no matter what format you are working with, no?
 
The P2 Viewer Plus has verification. You have to activate the premium features. It appears that not even one rep at Panasonic knows the costs for this. Unfortunately I complained (& many others) so much about overall functionality that it got pulled. Will take more time for R&D.

As much as I hate to, I'm seriously considering getting into LTO-6 tape archive backup for important raw P2 footage. HDD is fast but has limitations on long-term storage. Backing up to 2 hdds and migrating it every year or so to a bigger capacity one so far works out for me. I heard that within the decade, there should be at least a 20 Tb single SATA hdd. Now we're only at the 4 Tb mark. Blu-Ray disc is just too tedious to archive 3-4 Tb at a time.
 
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