Strange DVD picture

[geeees]

Hi Everyone,

I've realized that the picture of many widescreen DVDs (PAL) don't have a straight upper edge, but it has a step in it. It goes all the way through the movie and of course the ripped movies have the same problem as well. Here is a screenshot to make it easier to understand what I mean.
The problem occurs regardless player or computer (I don't have a TV, so no clue about this).
I was looking for answers on the web without success.
Does anyone know what is this and if it can be get rid of in the ripping process?
Thanks a lot for your help in advance!

[Ghitulescu]

What kind of image is that that has 1023x767 pixels? Ripped or screen captured DVDs should always be 576 or 480 pixels height.

The half lines are part of the standard. Before explaining you more I need to know or to see a real image from that DVD, because not all WS DVDs have the 2 halflines (it should also be one below).

[geeees]

Hi!

Thanks for the reply!

The thing is, I don't have the DVD on me anymore, I have to dig out one with the same half line feature. The screeshot was made by print screen (I guess that explains the abnormal hight of the pic). I've tried to use VLC and Gomplayer's snapshot, but it didn't work for some reason. I didn't know the size of the image is of importance.
If I remember correctly, the hight was 576 pixel.
Actually I've never noticed the half line on the bottom...

[geeees]

OK, I've found another DVD with the same feature.
And guess what, there is a half line on the bottom as well :)
I managed to make a proper snapshot with VLC:

[manono]

...and if it can be get rid of in the ripping process?
Crop it away and add back the black when reencoding. Since you resized the picture to some screwy dimension, I can't give a AviSynth specific script. My guess is that it was caused by the video being slightly off-axis

In the second picture, are you talking about the very thin lines that extend partway across the picture? Crop them away and either add back black or resize to do away with the black line entirely.

[geeees]

Thanks manono!

I never really bothered to crop before ripping, but now I did and voilà, the half lines are gone.

But I'm still waiting for Ghitulescu's reply. He mentioned that those half lines are "part of the standard". I'm wondering what he meant with this.

[Ghitulescu]

Well, as until HDMI/DVI didn't appear on the market, it played just a marginal role, whether a video was digital or analog stored. Once the interface (player -> display) was analog, then it had to follow the standards for analog signals, in your/our case PAL.
The PAL image starts with the second half of the first line, continues with the third one, then with 5th and so on, goes on the next field, and ends with the first half of line 576.

The reason was the state of the technique back in the fourties. You would also notice that the analog lines are also not perfectly horisontal, at least it was so for a long period of time.

Get a book, a standard, google or browse wiki if you need more. But it's not important for your daily work. It's something for perfectionists.

[geeees]

Hi Ghitulescu,

thanks for the short explanation. Though I wouldn't describe myself as a perfectionist, it looks better without them 2 half lines. And it's really just a few seconds to set up before the encoding.

Thanks again!

[Ghitulescu]

Hi Ghitulescu,

thanks for the short explanation. Though I wouldn't describe myself as a perfectionist, it looks better without them 2 half lines. And it's really just a few seconds to set up before the encoding.

I repeat myself: don't get rid of those 2 half-lines if you intend to play the image through an analog connection (FBAS, Y/C, RGB, YUV - the latter 2 in SDTV), because the player would recreate them again.

[geeees]

The chance of playing these movies on an analog device is rather small, but thanks for the hint anyways!

[Ghitulescu]

through an analog connectionThe chance of playing these movies on an analog device is rather small, but thanks for the hint anyways!
Analog connection not device.

[geeees]

Sorry, apparently I missed your point.
Here's what I was trying to say: I buy a DVD and want to back it up but don't have the capacity to save it in DVD format, so I want to encode and put it in an .avi or .mkv container. Before encoding I get rid of the half lines by cropping. I will only play this file on my laptop or PC. Am I all right then, or doing something useless/stupid by cropping?

[loekverhees]

If you are only playing it on your PC/laptop, then cropping is fine.