how to invert field order with ffmpeg

[marcorocchini]

Hi,
how can I reverse field order in ffmbc or ffmpeg?? thank all cats

[Selur]

afaik. there is no option to automatically change the field order, but you can enforce one:

"-top 1" -> tff
"-top 0" -> bff sets to bottom field first
"-top -1" -> same as input

[jagabo]

You can reverse the field order by cropping one scanline off the top and adding on on the bottom. Or vice versa.

[poisondeathray]

https://www.ffmpeg.org/ffmpeg-filters.html#fieldorder

-vf "fieldorder=bff"
-vf "fieldorder=tff"

The transformation is done by shifting the picture content up or down by one line, and filling the remaining line with appropriate picture content. This method is consistent with most broadcast field order converters.

If the input video is not flagged as being interlaced, or it is already flagged as being of the required output field order, then this filter does not alter the incoming video.

It is very useful when converting to or from PAL DV material, which is bottom field first.

Not sure what " filling the remaining line with appropriate picture content" means. You should experiment with it




https://www.ffmpeg.org/ffmpeg-filters.html#phase

Delay interlaced video by one field time so that the field order changes.

Not sure which one works better

[jagabo]

"phase" should work better with YV12 -- no blurring of the chroma.

[marcorocchini]

for kindness, an axample of use of phase?

ffmpeg -vf "phase=b" .. ?

[marcorocchini]

You can reverse the field order by cropping one scanline off the top and adding on on the bottom. Or vice versa.

ffmbc -i input.avi -target imx50 -aspect 16:9 output.mxf


for kindness, how I have to change the catcommandline to reverse field order? -vf crop=? thanks

[poisondeathray]

for kindness, an axample of use of phase?

-vf phase=b