1024x432 MPEG-2 to H264/MPEG4 encodes render as 576x432

[SiRGadaBout]

Hi,

1) I drag and drop an EyeTV-recorded MPEG-2 file onto FfmpegX. It displays various details, such as the resolution - in this case 544x576.

2) I determine that the pixel ratio for the encoding is 32:17, and that the aspect ratio for the film (after cropping to remove letterboxing) is 2.35:1. So, I choose an output resolution of 1024x432.

3) I choose (1) MPEG-4 to encode and as a container, (2) choose H264 to encode, MPEG-4 as a container, and deselect all video encoding options in the interests of a speedy rendering (these being trial runs). For the same reason audio is not encoded.

4) I click "Encode".

5) I receive an output file in each case that is correctly cropped but not the correct aspect ratio, but rather 576x432 (or something similarly square-ish, and distinctly un-cinematic)

Can someone tell me why this has happened three times so far? I'm sick of wasting hours on pointless encodes…

[Case]

Can someone tell me why this has happened?

I can confirm that the display aspect ratio for ffmpeg mpeg4 is off (4:3 instead of 2.35:1), at least for that resolution, but not for H.264 (mencoder or x264). It is a presentation thing, as the file does have the whole 1024x432 resolution video in it, even if displayed at 576x432. However my test H.264 video files were presented in their intended aspect ratio.
I don't know why it happens. I wouldn't rule out a bug in ffmpeg, as mencoder and x264 showed different behaviour.