aspect ratio problem from 1280x720 to 720x480 (quicktime)

[Johnny Cheung]

Hi,

I am trying to export some footage I shot using the HVX200 720p, the source is 1280x720 (23.976fps), and I need to get it to an uncompressed quicktime file in order to transfer it to digibeta tape.

I use premiere cs4, the problem I have is that when I choose quicktime and encode it as "dv ntsc widescreen 24p", the aspect ratio of output file is fixed to 720x480, and the encoded footage looks compressed a bit as the aspect ratio is wrong (correct downsample ratio for 1280x720 should be 720x405), and if i choose "uncompressed yuv 10bit 4:2:2", it does allow me to reset the aspect ratio, however when i set it to 720x405, the preview window shows the output file with two vertial matte bar on the right and left side. since i dont have the extra codec to see the result of the uncompressed quicktime video, i didn't try to actually proceed with the encoding.

So my question would be how i can fix it to make the aspect ratio correct? Should i proceed with the 720x405 for the uncompressed encoding? And i know the digibeta has to be at 720x486, so in that case, how should i encode the file?

thanks

 

[Cranky]

> when I choose quicktime and encode it as "dv ntsc widescreen 24p",
> the aspect ratio of output file is fixed to 720x480

This is not aspect ratio, this is the frame size in pixels. It is the same frame size for both 4:3 and 16:9 video. You need to set proper pixel aspect ratio whether it is widescreen or 4:3. For 4:3 you also need to pan&scan the center portion of your widescreen source to avoid distortion.

I don't know whether quicktime supports aspect ratio; for example AVI container has no aspect ratio flag, while WMV does have. See, I am a PC guy, I don't know much about Macs. With AVI, you can export to it and it will look distorted if you watch it with the default 1:1 AR. But if you know that it has to be 16:9 for example, you can set aspect ratio in a video player. I don't know whether this approach will work for you.