Resolution & Aspect Ratio

[markf78]

i am trying to use ffmpeg to convert video to my iPad which has a screen resolution of 1024x768 (4:3). my source video is 720x304 with a pixel aspect ratio of 1:1 and a display aspect ratio of 45:19. my question is what settings should i use for the frame size and why? also, i thought i read somewhere that changing the DAR in the output video leads to a distorted picture? is this true? what do i need to do to preserve the picture quality? any help would be greatly appreciated.

[hech54]

First thing to do is tell everyone exactly what type of video it is.....second thing to do is cut a tiny 15 second sample of that video and experiment with that.

[markf78]

it's xvid encoded (mpeg 4 part 2 asp) 23.98fps video in an AVI container...

[hech54]

http://www.dvdtoipads.com/ipad-faqs/ipad-video-format.html

[Alex_ander]

If you want numbers. Probably you want to letterbox it rather than crop (low initial resolution). Then to find the new height of the video after resizing its width to 1024, take the ratio of DARs and multiply it by full display height:
new_height=(4:3/45:19)x768=432;
fill the rest (totally 768-432=336) with black horizontal bars, then it will keep proportions.