What causes this bending/bowing of video? - Page 2

deter · #21 08-21-2011, 06:35 PM

jmac698,

Only 1 drop out, or streak in the picture.....Please check again.....

As far as the dup frames. Don't really care if you guys believe me or not. Uploaded the three frames were the skipping is.

They are hard to find in the video or videos. It takes a trained eye and knowing how to look for them.

THAT EVEN GOES FOR SCROLLING OVER THE FRAMES 1 BY 1

It works like this......

Frames 1,2,3,4,5,6,7,8,9,10,11,12,13,12

If I wrote this out from 1 to 5,000, could you find the double frame.....Yea but it wouldn't be that easy....

jmac698 · #22 08-21-2011, 08:19 PM

Deter,
I do believe you! Could you tell me what software you are using to view the dups?

As for the dropouts, I only noticed one - you have good eyes to find more than me! However, once I found one I wasn't trying hard to find more.

I did notice something strange about your dup.mpg file, at first I opened it in Avisynth with a different command, which gave me 8 frames and they were dupped from frame 4-8, in the same pattern you describe, 1 2 3 2 3..., and then I used DGINDEX instead, which gave me only 3 frames. I think there is something about the file or the software used to view it which causes this problem. Maybe I can look at the timestamps....

Please don't take offense

Update: I see nothing unusual about any of the files. My conclusion is that it's related to the software you are using. Hopefully this is helpful to you, as you may be getting unexpected results in other projects with your software.

admin · #23 08-21-2011, 08:31 PM

I opened the MPEG video "bending.mpg" in Womble MPEG-VCR, went frame by frame, and don't see a single duplicated frame. I don't like DGINDEX, as I've seen problems like this for 10 years now. When using Avisynth, I'd much rather use one of the FFMPEG source inputs (ffvideo, I believe). Or simply convert to Huffyuv AVI with VirtualDubMod, then process the AVI (not MPEG) in Avisynth.

The bending errors is clearly some sort of timing issue, but it may not be caused by problems corrected by a TBC. The aforementioned guess on luma values causing chaos is sensible.

NJRoadfan · #24 08-22-2011, 11:14 AM

Quote:

Originally Posted by admin

The bending errors is clearly some sort of timing issue, but it may not be caused by problems corrected by a TBC. The aforementioned guess on luma values causing chaos is sensible.

I've seen similar errors on cheap CRT TVs depending on the content. Bright areas will cause the video to bend on those too.

admin · #25 08-22-2011, 11:18 AM

I saw this kind of error on my local CBS station last year. Several episodes of CSI had bright flashes that distorted the video somewhere in the uplink process -- it wasn't an issue with my HDTV. It caused a jump of several lines, which was only obvious because the CBS eyeball logo bounced each time it happened. I saw this several times throughout the season. The same episodes viewed on re-run, on another channel some months later, were not flawed in this way. In fact, I think the re-runs were of better tonal quality, whereas the original run seemed to be in the wrong colorspace (clipped whites and darks, giving "rich" colors, albeit inaccurate).

Same error family, but visually distorted in another way.

jmac698 · #26 08-22-2011, 12:20 PM

I have 5 recordings of the same thing from different channels, the colors are all different, even hd channels have different colors. I think Fox turns up the colors to make it look better. I wrote a filter to determine exactly how the colors are being manipulated, I should be able to find out what they are doing.