SD anamorphic is 4:3. On replay the TV or computer should stretch the image back to 16:9. You could make a file that was 1024 x 576 which is true 16:9 square pixel.
What is the file for? The choice of DV codec seems a little strange as it is a lossy codec and not a lot smaller than IMX
Thanks for feedback.
The footage didn't look squashed in FCP, but when I opened the exported file in quictime, it was 4:3, with a squashed look, giving the impression it was 16:9 put in the wrong frame.
The footage is going to be broadcast on a norwegian kids tv channel, and the standard format is IMX50.
I solved my problem in this case, by taking my portable harddrive with footage onto a computer at the tv station, and lifted the footage from the time line to one of their publishing sequences in FCP.
However, I still don't know exactly the right settings in Compressor to use for footage shot 720x576 anamorphic in IMX50. If I make it 1024x576 like you say, wouldn't it make the quality of the picture lossy?
What codec would you recommend instead of the one I used?
SD broadcast is 720 x 576 in PAL countries. A 16:9 sequence is actually anamorphic squeezed into a 4:3 frame. This is normal. If you want to create a file for the web that displays true 16:9, the pixel aspect is 1024 x 576.
So editing for SD PAL you chose the 720 x 576 anamorphic sequence settings. The best codec for broadcast would be ProRes 422. IMX and DV are compressed formats and you will experience quality loss, particularly with graphics and text in DV.
So in future capture as ProRes422 720 x 576 anamorphic and edit with a matching sequence.