Black frames? Flickering?

[joeydingding]

Hello,


I'm currently working on a short and in the test runs I see that I get black frames in my video.

What is happening here?

[Walter Schulz]

Please!
Give at least some basic information about version and settings used or do you want to read an obvious answer like "You just described it: You got black frames in your video!"?

[joeydingding]

Hello, Im sorry!

I'm using the latest nightly build.
I'm using Felix 16GB 1000x UMDA 7 card
16:9 at max (continuously)
global draw live only

When I play the video in mlrawviewer I got black frames. The timeline stops when the black frames appears. But resumes afterwards.   Like eye-blinks

[Walter Schulz]

Movie tab -> RAW video -> [Q] -> Frame skipping
Which setting do you have?

[joeydingding]

frame skipping is off.

[Walter Schulz]

Well, the obvious one it is not.
I hope Baldand will jump in to solve this. Means: I'm not working with MLRAWviewer and have no expertise here.

[joeydingding]

what do u use?

[Midphase]

Hello, Im sorry!

I'm using the latest nightly build.
I'm using Felix 16GB 1000x UMDA 7 card
16:9 at max (continuously)
global draw live only

When I play the video in mlrawviewer I got black frames. The timeline stops when the black frames appears. But resumes afterwards.   Like eye-blinks

First of all, what camera are you using this on? You have 3 listed in your signature...and two of them can use ML. Secondly, the "latest nightly build" isn't good enough, you have to give us a date, the builds change on a daily basis. Thirdly, I haven't heard of "Felix" and I suspect this issue is related to the card. Fourthly, what resolution? Seriously, 16:9 at max means nothing without knowing what camera you're using or if you're in crop mode or not. Lastly...is Global Draw enabled while recording or not?

Please go and do some homework and come back when you can ask reasonably informed questions and give out the pertinent information that allows this community to try and help you.

[joeydingding]

I use the 7D
I use batterygrip
I use magiclantern-Nightly.2014Jul18.7D203
I shoot 1728x972
Global Draw off while recording !

[Midphase]

Thank you, my diagnosis is that the problem is your card.

I'd suggest that you run some benchmarks and see what write speeds you're getting from it.

[Walter Schulz]

Not sure about the diagnosis. Shouldn't "Frame skipping = off" just stop recording?

@joeydingding: The black frames doesn't by any chance happen after about 4 GByte?

[Midphase]

Not sure about the diagnosis. Shouldn't "Frame skipping = off" just stop recording?

@joeydingding: The black frames doesn't by any chance happen after about 4 GByte?

I don't think the black frames are skipped frames.

[Walter Schulz]

You might want to explain?

[Midphase]

I think they're corrupted frames, but not necessarily skipped frames. I suspect the card might possibly be having some write errors, and if that's the case then it wouldn't trigger for recording to stop since no frames are actually being skipped.

A quick test would be to reduce the resolution to about half that, and see if the errors still occur. I suspect the footage will look fine since the card probably has enough bandwidth to handle the slower data rate.

Just a speculation.

[joeydingding]

In think they are corrupted frames.. I'm getting distorted frames now.

I think it's the cheap chinese card. I will get a komputerbay soon and post more info involving this problem.

Thanks guys.

[joeydingding]

Okay guys I did some testing with lower resolution:

Lower resolution no black or corrupt frames anymore. Guess the card is bottlenecking on me. But!

The battery grip is a problem too. I can record less frames with the battery grip attached. I also have less memory. More fps drop in preview mode (black and white).
The sensor is cooler with battery grip attached..

Weird.. Any battergrip users who encountered the same?

[Midphase]

Battery grips can sometimes cause issues. I know for instance that Canon recommends removing battery grips when updating the firmware...so it must have some effect on the camera.

I think if you get a good Komputerbay card, your problems will go away and hopefully you can continue using the battery grip.

[budafilms]

Okay guys I did some testing with lower resolution:

Lower resolution no black or corrupt frames anymore. Guess the card is bottlenecking on me. But!

The battery grip is a problem too. I can record less frames with the battery grip attached. I also have less memory. More fps drop in preview mode (black and white).
The sensor is cooler with battery grip attached..

Weird.. Any battergrip users who encountered the same?

Battery Grip is cooler for the distance of the battery to the processor.
The battery produce some degrees up.