Need a way to specify field order for lossless input

[oyvindln]

I was looking into this tool as something to suggest to people to use for easily converting, processing and and deinterlacing videotape captures, but it isn't usable on captures in lossless file formats since there is no way to specify field order for deinterlacing. None of the common lossless codecs like ffv1, utvideo, huffyuv etc have any flag for field order, and since basically all capture devices capture in top field first when using uncompressed output while ffmpeg defaults to bottom field first when order is not specified the output is deinterlaced with the wrong field order.