Set interlacing information in QuickTime

Question

I'm trying to set the correct interlacing information via the QuickTime 7 API on a movie that I am creating.

I want to make my movie progressive scan but when I visually check the output, every frame is squashed into the top half. So even though I make sure QuickTime knows my movie is kQTFieldsProgressiveScan it still gets confused.

This is what I am doing:

myCreateNewMovie(...);
ICMCompressionSessionOptionsCreate(...);
BeginMediaEdits(media);

myCreate(ImageDescription with appropriate FieldInfoImageDescriptionExtension2);
SetMediaSampleDescription(media, ImageDescription);

and then when writing each frame I add the same description:

ICMImageDescriptionSetProperty(myFieldInfoImageDescription, ...);
AddMediaSample2(...);

Answer 1

From various bits and pieces on the net I got the impression that setting the sample description for the media was getting overwritten. Now I'm setting the FieldInfo data inside my ICM Encoded Frame Output callback and it seems to be satisfactory.