last attempt

[chobo321321]

I am trying to get rid of flickering (hard to notice with dark colors very noticable with light colors) where the image meets the letterboxing (on both the top, and bottom letterboxing).

My source is a 640x360 Anime encode (16:9) aspect ratio.

I encoded it using the following script.

AVISource("19.avi", False)
ConvertToYUY2()
LanczosResize(720,360)
AddBorders(0,60,0,60)

I then applied a pulldown using pulldown.exe using the following parameters.

pulldown.exe 19.m2v 19-pull.m2v prog_seq [i] prog_frames [p]

I played the burned DVD using my computers DVD player, and it played perfectly fine, so the problem is something with the TV, or DVD player for the TV. The only thing I could think of that might be the problem is whether to use progressive, or interlace for the source setting.

The encode was done using xvid 4.0 codex, and is an AVI file. I have no idea whether the source is progressive, or interlace, and I have no idea how to check. I have tried loading up the avi file in DVD2AVI, but it doesn't load up. I'm not even sure if that is the problem. I have searched the forums, and google, and could not find much relating to flickering only by the letterboxing(at least only noticable there).

Any help is appreciated.

[sacajaweeda]

29.970fps = interlaced
23.987fps = progressive

Don't rely on a computer monitor to test your stuff with. The monitors are progressive so the refresh rate isn't the same as a standard TV.

[chobo321321]

Thanks for clearing that up. I have been doing all my encodes using progressive, and there still is flickering by the letterboxing. I have run out of idea's on what could cause this.

[sacajaweeda]

What is your source from? Something you captured? VHS? Is it from another DVD? I get a bad edge every once in a while from VHS stuff. If that's what you got just crop it a line at a time till it stops and then add extra lines to your border.

[chobo321321]

The source is an anime-dvd-rip. When I check the AVi with Gspot it reports it to have a frame rate of 23.97, so I'm assuming it's progressive. The source file plays fine on my computer with no problems. Even the burned DVD plays fine with no flickering, it's just when I play it on my TV it comes up with flickering by the letterboxing.

The source file has an aspect ratio of 16:9, and a res of 640x360., so the file had no letterboxing to begin with, but since I had to convert it to a res of 720x480 I added a 60 pixel letter box on the top, and bottom.

[sacajaweeda]

I would try either resizing it to 480 line vertical resolution or if the extra 120 lines distorts it too much maybe try using a different color subpicture to letterbox it that contrasts better than the black that is making the flicker so noticeable.

[junkmalle]

I played the burned DVD using my computers DVD player, and it played perfectly fine, so the problem is something with the TV..

Exactly. The display on the TV is always interlaced. At the top and bottom edge of a letterboxed picture there can be a sharp discontinuity between light and dark. This makes the flickering of NTSC most noticable.

The way to get rid of it is to antialias the edge of the picture with the black background. Since you don't have access to the original film or a high resolution capture, the closest you can come is to darken the top and bottom scan lines of the picture by about 50 percent.

[chobo321321]

Exactly. The display on the TV is always interlaced. At the top and bottom edge of a letterboxed picture there can be a sharp discontinuity between light and dark. This makes the flickering of NTSC most noticable.

Finally someone understands the situation Do you know how I can go about anti-aliasing the top, and bottom edges? The source SVCD has no letterboxing, but I add it in there so it looks right. Thanks in advance.

[junkmalle]

[quote="chobo321321"]

Do you know how I can go about anti-aliasing the top, and bottom edges?

Tricky. The most obvious solution requires a darken and reduce contrast filter that you can limit to a wide one or two pixel high box. One box at the top of the image and one at the bottom. I don't know of a filter that does this though.

After thinking about it for a while I may have thought of a fairly easy solution: use a logo filter with an alpha channel. Make your logo a full screen black image. For the main part of the picture make the logo transparent. At the very edges of the picture make one scan line 50 percent transparent. If it take two scan lines to get rid of the flicker make one about 66 percent transparent and one 33 percent. For the letterboxes it doesn't matter if the alpha map is transparent or not.

An image like this should work for the alpha channel

[chobo321321]

Thanks for the help junkmalle! I'm gonna give your solution a try. I'm kinda surprised though, that there are almost no posts, topics, or guides for this kinda problem. You would think that more people would have tried converting a SVD witha 16:9 ratio into DVD format.

[junkmalle]

Chobo, I ran a little test with VirtualDub and it's logo filter. The logo/alpha channel technique seemed to work. You may need to fiddle around with just how transparent the alpha channel needs to be to get optimal flicker reduction.