DV Info Net - FCP export dimensions and sequence settings

There isn't always one way to do something. With anamorphic source (aka wide screen squeezed into a not wide stored frame), once you master all the knobs and switches, you can choose the one you want.

For easiest editing of material shot in the same format, you want the sequence to match the source to minimize rendering. "Squeezed" SD video means 853x480 pixels were squeezed into 720x480. It does this by storing pixels that are rectangular (taller than they are wide) so as to fit in a 720x480 frame. Don't ask why as it's a whole discussion in the history of television. CCIR 601 specifies these skinny pixels. It's the DV standard. FCP 7 is good about seeing what the source is and setting the sequence to match it the first time you drag material onto an empty sequence.

You can export your sequence as squeezed denoting the pixels are CCIR 601 aspect ratio and packaged in a standard 720x480 frame. In order for it to be played properly, the player software must recognize the PAR and frame size. If it does, it will display it as 853x480 and things will look right. This approach depends on the playback software interpreting the file correctly and the image quality of the pixel expansion is determined by the player.

Alternatively, during the render, you can specify an output frame size of 853x480 and a square PAR. This eliminates the anamorphic (squeezed) aspect of your footage from this point onward. The quality of the expansion is determined by the rendering software. It also needs to properly set the file settings so playback software plays it correctly (and not interpret it as squeezed).

I've seen variation over the years with rendering and playback software as various cameras were released and bugs fixed etc. I suggest some experiments using the rendering and playback software you have.