[export_ffmpeg.so] Selected dvd profile, general video type for video
[export_ffmpeg.so] warning: Interlacing parameters unknown, select video type with profile
[export_ffmpeg.so] Set interlacing to unknown

[export_ffmpeg.so]: INFO: Selected dvd profile, ntsc video type for video
[export_ffmpeg.so]: INFO: Set interlacing to bottom-first

[export_ffmpeg.so] Selected dvd profile, pal/secam video type for video
[export_ffmpeg.so] Set interlacing to top-first

[export_ffmpeg.so] warning: Interlacing parameters unknown, use --encode_fields

--encode_fields C

enable field based encoding (if supported) [off]
This  option  takes  an argument if given to denote the order of
fields. If the option is not given, it defaults  to  progressive
(do not assume the picture is interlaced)

Valid codes for C are:

p   progressive (default)

t   top-field first

b   bottom-field first