PDA

View Full Version : Footage Gltiching/Freezing



brownpaperbagproductions
09-20-2009, 09:08 AM
We're shooting a feature that takes place in the woods, I've been shooting at 25p 1080 but switched to 50p 720 to avoid mud, we shot something and when we watched it on the camera playback it froze in a couple spots, we just thought maybe the card was getting full and the camera was slow on playback, upon watching it again after transferring it to FCP we realized that freezing was really a glitch in the footage.

Has anyone had this freezing problem?

We've been using the same SD card as the 25p footage and haven't had problems with its speed, so I don't know what it could be?

To be more specific, it freezes then jumps in time to where it would have been if it hadn't froze.

Oedipax
09-20-2009, 10:06 AM
What class SD card were you using? I've been using a Class 6 with mine and haven't had any freezes yet.

AdrianF
09-20-2009, 12:26 PM
Had freezing a couple of times, exactly as you describe. On each occasion the card was either full or I hadn't reformatted after heavy use, so I'm fairly sure this is card related. These only happened on a Kingston 8gb class 6, I haven't experienced it on any other card.

Ozpeter
09-20-2009, 04:30 PM
Are you sure the shutter speed was manually set?

Was there anything particular happening in the shot at this point, such as something passing across the shot close to the camera?

Does the GH1mtsCheck utility confirm the problem?

brownpaperbagproductions
09-20-2009, 06:32 PM
One 8gb PNY Optima SDHC class 4
One 4gb Sandisk Extreme III SDHC class 6.

I formatted the 8gb and it still froze. I used the 4gb unformatted but it, I suppose more or less justifiably, froze from being unformatted.

But what's weird is I havn't had this problem before. If you say its cause the card is slow, was I just like the first 20 hours of use on it when it never had this problem?

I guess I can try to format the faster card but is there really no other explanation?

Yes, there was some movement close to the lens, about 5 feet, with lots of forrest details, and yes the shutter was manually set at 50. Its not strobby, it holding a frame for about 8 frames then jumps in time like it just caught up.

pailes
09-20-2009, 11:53 PM
Is it PAL or NTSC? The PAL version seems to have this bug but so far the NTSC version seemed to be fine, but probably the NTSC version suffers from the same problem.

AdrianF
09-21-2009, 06:59 AM
I guess I can try to format the faster card but is there really no other explanation?

Each time this has happened to me, I have been filming trees, once in a forest and another time at a waterfall surrounded by trees on either side. It could be that the codec is working at the top end of it's performance and if the card is struggling at that particular moment then it chokes. It looks to me just like dropped frames and that is what I've put it down to.
This is just a theory as I haven't seen it happen any other time and you say that you were shooting in a forest too, so I guess it's either that or the camera gets scared when it's out in the woods and shits itself ( or muds itself ).

pailes
09-21-2009, 07:53 AM
Each time this has happened to me, I have been filming trees, once in a forest and another time at a waterfall surrounded by trees on either side. It could be that the codec is working at the top end of it's performance and if the card is struggling at that particular moment then it chokes. It looks to me just like dropped frames and that is what I've put it down to.

I can confirm this observation. Also had similar thoughts on the topic already:
http://www.dvxuser.com/V6/showthread.php?t=175165&page=2

Barry_Green
09-21-2009, 08:24 AM
Something to try -- over in the Canon pages, Tim Smith of Canon is advising everyone using a 5D Mark II to always use UDMA cards. He said that some banding and artifacting can happen on non-UDMA cards, but that it doesn't happen with UDMA cards. He said that the working theory is that when the card can't keep up with the data flow, the camera dumbs down its compression (compromising quality) to match what the card can accept. He says with a UDMA card, that never has to happen.

Now, I don't think SDHC even has the option of UDMA, but it certainly can be faster than Class 4! So if you've got mud, or frame glitching, or anything other than great performance, try using a Class 10 card. It might be worth a try.

brownpaperbagproductions
09-21-2009, 09:43 AM
Well, I guess I have to get a new card then. Thanks guys.