I'm having aliasing problems

[DougGorius]

I'm converting an .mov file, which is 1280x544 pixels and with a framerate of 23.976, to an mpeg-2 encoded dvd, with the 23.976 framerate kept, the 3:2 pulldown set and in 16:9. But the result always has lots of aliasing, and it looks horrible. For some reason, when I make the dvd 4:3 instead of 16:9, the aliasing goes away, but I need it to be 16:9 in the best quality possible. Can someone help me? Thanks!

[tomlee59]

Aliasing? What kind -- spatial or temporal; luminance or chrominance, or both? And do you have a screenshot? And have you viewed the result on different monitors to verify that it's in the source, and not a display artifact? I am skeptical that you are actually seeing aliasing, which explains all these questions.

[DougGorius]

I think it might be stairstep aliasing. Could you describe what those types of aliasing you said are?

[tomlee59]

The fact that these terms are unfamiliar to you suggests that you may have jumped to conclusions on the diagnosis. I'd be happy to offer you a dissertation on the finer points of sampling theory, and how sampling below the Nyquist rate can cause spectra in reconstructions to appear at different frequencies than their source, but that ain't going to solve your problem. Also, because I can't imagine how serious aliasing could occur with modern tools (at least, not without a lot of effort), let's pretend you never mentioned aliasing, and go back to the "it looks like crap" description.

If you could provide details on what the source characteristics are (res, frame rate, codec, bitrate), what tool you are using for the conversion (I'm assuming ffmpegx, because you posted here, but please confirm), what settings you've chosen, etc. If you could post the contents of the logfile (click on blue "i" in Progress pane), that would be helpful, too.

And if you could provide a little more detail on the precise nature of the craptitude, that would help diagnose things. Are you seeing macroblock artifacts in high detail/fast motion areas? Are you seeing "comblike" teeth in laterally moving objects? Judder? Etc. The more specific you get, the more likely one of us can figure out a solution.