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-   -   Bottom line flickers! It's driving me crazy (https://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/93017-bottom-line-flickers-its-driving-me-crazy.html)

Josh Green May 7th, 2007 10:22 PM

still nothing
 
I've still found nothing that helps the situation. I ended up just placing a mask over the footage on the top and bottom and re rendering. That took it away.

Martin Trotter May 9th, 2007 03:44 AM

not an ideal solution. I've posted on another forum to see if anyone can come up with anything.

Gert Kracht May 9th, 2007 04:30 AM

It may seem like a strange question, but what sort of monitor do you have? CRT of TFT?

Just because a good friend had similar problems with capturing. His CRT had a very strong magnetic field and that caused several problems during capturing. It also could be another device what does the same.

Who knows....

Martin Trotter May 9th, 2007 04:44 AM

mine is a rather large CRT. I would doubt it, but you never know. Never had any trouble with previous camera.

Martin Trotter May 9th, 2007 06:17 AM

a reply from another board - what do you think?:

Here's what I see when we shoot 16x9 from a Digibeta.

The top scanline actually starts slightly less than half a scanline in. The bottom ends half a scanline out. You can see this when you examine the picture on a field monitor with underscan active.

Sort of like:

......................--------------------
--------------------------------
--------------------------------
... etc ...
--------------------------------
--------------------------------
--------------------......................

Normally these half scanlines are out of the visible picture area but you can see them on a 4x3 monitor with the 16x9 aspect ratio enabled.

If I use FCP to slow down this footage with field blending on, it interpolates these half fields with their blank siblings and produces a flicker in the usually black part of the scanline.

Take a close look at your footage and see if you have similar half scanlines at the beginning and end of your video frames.

As I say, if we are going back out to a proper widescreen display, these half scanlines would usually be out of the visible area and not a problem, however if we are letterboxing they are brought back into view.

Added to this, DV uses a different field order from nearly everything else and I think FCP now automatically moves it up (or down) a field to conform it which might produce this flicker at the bottom rather than at the top and the bottom.

Obviously, different cameras and we're in PAL land so your milage will surely vary.

My solution is to crop off the top and bottom scanline.

Ben Hayflick May 9th, 2007 07:24 AM

I am seeing something similar in Vegas. Actually there are two problems, which may be related.

When I play back 16x9 24F SD footage from the tape, the video looks perfect on my JVC CRT monitor, using an S-Video connection. It even works when I play it back from an old Sony TRV50 and not the A1, which surprised me as the Sony is neither 16x9 nor 24p, much less 24F.

Problem 1:
However, playback of the same footage in Vegas causes the bottom line of video to flicker annoyingly. I noticed it doesn't happen all the time- there is one clip where there's no problem, but then 75% of the way into the clip the flickering begins. Other clips have the problem all the time, and none are completely free of this problem.

Problem 2:
When I watch this footage play back on the LCD screen of my A1, the aspect ratio crazily jumps back and forth from 16:9 and 4:3 every several frames. Unwatchable. The Sony's LCD would do this too, but then pass a near perfect image through its S-Video out to my JVC studio monitor (near perfect because it shows Problem 1 as above).


I'm sure I'm doing something absurdly wrong, as I'm new to Vegas, 24p pulldown and the A1. Here's a list of the facts:

-16x9, 24F, SD, 2:3 pulldown mode A1 footage, captured by Sony TRV50.
-Vegas Project:
NTSC DV 24p Widescreen (720x480, 23.976 fps)
Frame Rate 23.976
"Allow Pulldown Removal when opening 24p DV" is checked
-Footage in Vegas Timeline doesn't show as 24 fps
-Footage looks fine when played back on CRT computer monitor, neither problem 1 or 2 showing


Can anyone help? It seems the A1 isn't causing the problems; as stated above the footage plays back clean from the tape. So, Firewire? I'm kinda lost.

Steven Dempsey May 9th, 2007 10:00 AM

I see this same phenomenon while watching some SD TV broadcasts on an HD monitor.

Steve Rosen May 9th, 2007 12:02 PM

I have noticed the problem many times with letterboxed video transfers from super16 film - so obviously the camera isn't an issue - as suggested, try lots of different TVs just to satisfy yourself...

Gert Kracht May 9th, 2007 01:34 PM

Quote:

Originally Posted by Martin Trotter (Post 675407)
mine is a rather large CRT. I would doubt it, but you never know. Never had any trouble with previous camera.

Just for once....try to put distance between the camera and the monitor as much as possible.
You could end up putting the camera on the ground, a chair of something else.

Maybe the old camera was a bit more shielded than the A1.

At least, trying does not hurt and who knows....

Josh Green May 17th, 2007 06:09 PM

Hey Martin
 
Hey Martin, I figured out a fix for the bottom line flicker. I was capturing in NTSC DV anamorphic but my sequence timeline was set to just NTSC. On my latest project, I captured in anamorphic and set my sequence to anamorphic and by golly when I sent it through to DVDSP and authored the DVD, the bottom line flicker was gone. Maybe this will help you.

Josh Green May 21st, 2007 11:56 AM

never mind
 
Never mind, the flicker is still there. I'm on a new project now and it's there and clear as day. It's bastardly!


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