several shots untransferable from SDHC card

[Michael Slowe]

Marten, why not take the files out as video directly on to your drives via the SDI output from the camera? This may not be the best route generally but it should get the stuff out that you are having problems with, especially as you state that the clips do play from the camera .

Michael Slowe

[Rafael Amador]

Michael Points a solution.
Normally those are clips that haven’t been properly closed (too fast stop/rec?).

I’ve read a post I think (from Craig) about a similar issue.
The solution was more or less to make a “subclip” from these wrong clips and export not the full length.
I can not remember if he did it “in camera”.
I’ll try to find the info.
rafael

http://www.nagavideo.com

[Rafael Amador]

Here it is:

https://forums.creativecow.net/readpost/142/867403#reply_box

rafael

http://www.nagavideo.com

[Marten Berkman]

Rafael and Michael, thank you for your feedback!

First I must share more of the situation that i discovered:

When XDCAM transfer in FCP hit a corrupted clip, it balked at all subsequent clips, giving me an error response. Thus i assumed all subsequent clips were affected. When I tried a random selection of those clips in camera, they played fine.

turns out that I was playing good clips that remained on the card. the first clip of the group that XDCAM transfer hung on would not play.

I opened XDCAM transfer independent of fcp, and found this more stable, in that i could preview a clip until it reached the corrupted point, though I still had to restart XDCAM transfer after it hit a corrupted point. I also noticed that the card registered “in use” even after XDCAM transfer was closed, was impossible to eject properly, and I had to restart the camera and restore media before executing USB transfer again.

So i thought, having a sense of where the corrupted point was, why not export only a selection of the clip before that point in XDCAM transfer. That worked. unfortunately one of the corrupted clips failed about three seconds in.

I then tried Log and transfer plug in in fcp, and was delighted to discover that at least even im portant corrupted clips were transferred successfully, though only to the corrupted point, without hanging anything. However, i was still missing important media.

(some clips would not transfer at all in log and transfer, and by situational deduction, i think these were clips where there was rapid stop/start of recording…i was still able to salvage them…read on…)

My friend Cory Trepanier had encountered a corrupted clip and his solution was to select short sections of the clip one at a time for export, which would work until a corrupted point was found. at least media was being successfully exported, albeit in pieces.

So i tried this in XDCAM transfer and was delighted to discover I could export media at the end of the clip. I did successive exports, working backwards, ie increasing the clip size until the corrupted point was hit and was no longer able to export.

So Rafael, same idea as Craig’s link that you sent me, though i am happy to say i was able to do the clip dividing in XDCAM transfer.

And thanks for the SDI suggestion, Michael, alas I do not have facilities to record SDI, though i was thinking i would be calling on a friend who does. I was also thinking doing at least an iLink out in HDV, but the material has to be recorded in SD, not HQ to do that.

Now the question remains, is this a corrupted card problem? or a problem of too rapid powering down, or recommencement of shooting? when i have time I will try to recreate this to discover if that isolates the problem.

It seems odd that a point midclip or near the beginning of the clip should be affected by powering down or recording again before the card indicator lights are green. However i am not familiar with the architecture of a clip’s data. Could it be that something recorded near the end is critical info for frames so much earlier in? or is the data recorded chronologically (except for key frames of course). perhaps this is neccessary for VBR?

A note of warning to those using log and transfer for xdcam: seeing as it can download a corrupted clip successfully up to the problem point, this may go unnoticed in a batch process until actually viewing the clip. However the downloaded clip length in your browser will indicate what was successfully captured, while the media length in the log and transfer window will indicate original shot length. scan and compare these two after log and transfer and any discrepancies will be clear.

whew what a long post for my initial problem! I hope sharing this will help anyone else finding themselves in this situation. Thanks Michael and Rafael for your help. If any light gets shed on whether this was a card issue, or a power down/stop/start issue, i’ll post it.

cheers,

marten

[Craig Seeman]

[Marten Berkman] “I’ve read about issues of shutting off the camera too soon, but this issue applied to several clips which were in succession before shutting off the camera, as well as isolated clips.
“
Starting to record a new clip before the light goes from red to green can also corrupt a clip and/or it’s metadata.

If the card throws a restore media error which in the camera, try that to fix it.
Also in camera try Menu/Others/Clip/Update which can fix the issue if it’s metadata related.

If the clip itself is corrupted, splitting the clip in camera can edit out the corrupted portion. In process it creates new metadata so the “good” portion is identified properly as a separate clip.

[Craig Seeman]

[Marten Berkman] “i am happy to say i was able to do the clip dividing in XDCAM transfer. “

Good to hear. In file based media it’s possible that the corrupted clip may also impact the metadata making the following clips superficially unplayable. It’s probably the file equivalent to a bad tape crease where one must find a way to get past the damage to play the rest of the tape.

In the end the EX is a computer writing a file and like any computer writing a file, a file or portion of can become corrupted.

At some point one of use should do a tutorial on the various ways to split the clips when one runs into this.

[Marten Berkman] “is this a corrupted card problem? or a problem of too rapid powering down, or recommencement of shooting?”

Again it’s not just powering down, it’s going into record before the red light (indicating a write is still in progress) turn green. If you’re not sure what that means that than may well have been what happened because you have to consciously look for that especially with SDHC since it finishing the record from buffer to card takes a few seconds longer than SxS.

I would certainly reformat the card and run it through the battery of tests that have been posted elsewhere on this list to check whether the card itself is in decline.

[Marten Berkman] “It seems odd that a point midclip or near the beginning of the clip should be affected by powering down or recording again before the card indicator lights are green. However i am not familiar with the architecture of a clip’s data. Could it be that something recorded near the end is critical info for frames so much earlier in?”

It might be a metadata issue since such things as SMI link multiple clips together. It may well be something that indicating a “false” EOF (end of file issue) that the metadata thought was mid clip. All speculation though on my part.

[Marten Berkman] “A note of warning to those using log and transfer for xdcam: seeing as it can download a corrupted clip successfully up to the problem point, this may go unnoticed in a batch process until actually viewing the clip. “

Just to be clear, you should be using Clip Browser with CRC checking when transferring files. CRC is a key check in making sure the data is transferred properly. Only after the file is transferred successfully should you then use XDCAM Transfer or Log & Transfer for wrap to .mov.

Did you use Clip Browser first. If not that may be a root of the problem. It may not fix it but it might catch it if the CRC reports that the copy does not match the data on the card.

[Marten Berkman]

Thanks Craig!

I find it interesting the camera firmware does not inhibit powerdown or recording when a writing action is not finished (a phenomenon I’ve grown accustomed to in my digital still camera!). I will definitely keep my eyes on the slot lights next time. It reminds me of working with the Red camera.

No I have not used clip browser first, and indeed, I see how it makes sense to if it can check the raw data on import. I was relying on the transferred version as my master copy, but having the raw data is ideal. what was i thinking? I am not familiar with the transfer function of clip browser, or CRC, and am downloading the latest version now to check it out.

next I’ll be wondering if there is any software to tweak the picture before wrapping as a .mov file…but that might be redundant. I suspect there is no extra information, such as in a RED raw file, to tweak before transferring to a .mov, since (if i understand correctly) no futher compression takes place in the transfer.

Many thanks for the heads up, and generous time and detail in your response. This has been an enlightening day.

[Jordan Dwyer]

Some SDHC Cards have bad sectors on them. When you record over that bad sector, the actual footage that is recorded in the bad sector will be lost but the footage before and after is still accesable. The trick is too find a way of playing the footage without going over the bad sector. This means to make in and out points before the bad sector and making a new clip in clip browser. If this happens to your memory card it will happen again to that memory card. This happened to me when i was using a sandisk card.

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[Craig Seeman]

If the card has a bad sector wouldn’t a reformat map out the bad sector. Of course one might not want to trust a card if sectors are beginning to fail.

[Brent Dunn]

Are you transferring into final cut directly from the camera? You should copy the BPAV folder onto your hard drive first, then do the transfer or conversion of the XDCam files.

Brent Dunn
Owner / Director / Editor
DunnRight Video.com