ffmpegX Input Resolution

[promoter]

Major:

With your help I've successfully created an SVCD from an iMovie project using ffmpegX 4.0a. However, there are black letterbox-style bars at the top & bottom of the screen, and I'm seeing distortion at the top & bottom of the image that would usually be hidden in the overscan area. At what resolution should I export from iMovie so that ffmpegX will crop off the sides, top, & bottom to avoid seeing the distortion? Thanks for your help!

[Macnewbie]

You do know that ffmpegx is upto version 0.0.4d now, right?

[promoter]

You do know that ffmpegx is upto version 0.0.4d now, right?

Yes, though I haven't gotten 0.0.4d to work yet. I can't find a way to tell ffmpegX whether to letterbox or crop the video. From the release notes, I don't think this has changed from 0.0.4a to 0.0.4d.

My source video is captured from a VHS tape. There are thin bands of distortion at the top & bottom of the frames of the captured video. These bands don't appear when viewing the original tape on the TV, so I assume they fall into the overscan area. All I want is for these disorted lines at the top & bottom to be cropped or pushed into the overscan area so I don't see them in the finished SVCD. Because the video is "letterboxed," I see the full captured frame including the distorted areas.

[squeed]

I don't think that changing the resolution on your current video source is going to matter. You need to crop that distortion out of your video. I think that MacMpeg2 Decoder can crop off that stuff for you.

You can find it on my site if you would like.

-Squeed
http://www.squeeds.com
VCD and SVCD Support for MAC

[promoter]

Squeed:

I'll try MPEG2Decoder 1.0b8 this weekend to see if I can crop out the distortion. I'd still like to know how to stop ffmpegX from letterboxing my SVCDs. I recall Major saying the black bars are added as needed, from which I inferred that sometimes they're not needed. It seems that this would be a function of the input video's resolution.

[squeed]

On the Mpeg-2 tab of ffMpeg there is a checkbox called "VOB Letterbox". I have never tried turning it off but I think it has something to do with the black bars.

Since movies that are presented with black bars are called letterbox it would make sense that, that is what it is.

Have you tired turining it off ?

-Squeed
http://www.squeeds.com
VCD and SVCD Support for MAC

[promoter]

Found the solution. The magic resolution for avoiding the letterbox bars in ffmpegX is:

720x540

I had exported at 720x480, and ffmpegX 0.0.4a added the black bars @ top & bottom. I figured it might have something to do w/the square vs. non-square pixel issue I've read about (but don't understand). After reading an article on it, I exported from iMovie @ 720x540 (a 4:3 ratio, like my TV). When I encoded a short clip in ffmpegX, there were no black bars @ top & bottom.

On the Mpeg-2 tab of ffMpeg there is a checkbox called "VOB Letterbox". I have never tried turning it off but I think it has something to do with the black bars.

I saw that checkbox when I looked more carefully tonight. And, I just now figured out why I couldn't get 0.0.4d to work. I needed to rename the QuickTime source file by adding ".MOV" to the end of the name. (Aside: Something should be written in a FAQ about naming conventions for the utilities used by ffmpegX, e.g., "input file name must end in '.MOV," "file/folder names can't have spaces," etc.).

I'm playing w/0.0.4d now to get the best results. Thanks everyone for your input.