[FFmpeg-user] Generate/Playback Interlaced (1080i) video with lavfi.

[Matthias, Thomas]

Hi,

I’m trying to generate some smtpebars with a script, and it works fine for 1080p video.  However, I’ve tried numerous combinations for generating 1080i video using the –vf tinterlace filter.  For example, if I want to generate 1080i50 video, do I use 25000/1000 as the framerate, and then –vf tinterlace=6?  This doesn’t seem to work.  I’ve also tried setting the framerate to 50000/1000 and then using –vf tinterlace=4, but that seems to be giving 1080p25 instead of true 1080i50?  I’m probably way off here, any help would be really appreciated.

Example command (not at all inclusive of everything I’ve tried):

ffmpeg –y –f lavfi –i “smptebars=duration=1:size=1920x1080:rate=25000/1000” –pix_fmt uyvy422 –vcodec rawvideo –vf tinterlace=6 smpte_bar_test.mov

More importantly, using the decklink output device, is there a way to playback an interlaced video?  Even if I try to playback a video that I know is 1080i, it always plays out as progressive from the decklink output device.

Thanks!