I have problems getting proper interlaced output with Shotcut 20.07.11.
I am working on a few old, but personally important SD videos (Super-8, VHS - i.e. all interlaced) using some advanced Avisynth scripts for cleaning them up. Furthermore, I am always using FFV1 as intermediate codec for all steps until the final x264 encoding.
I worked with FFV1 files before in shotcut and set every clip to “Interlace” and “Top/Bottom Field” manually after having loaded them into the playlist. On export, I chose FFV1, again “Interlace” and “Top/Bottom Field” enabled, and it works when I just put the clips next to each other in the timeline and add simple cross-dissolve transitions and fade-in/fade-out. Project settings are of course also set to PAL DV (i.e. 720x576, interlace enabled, 25fps etc.)
Now, I wanted to “repair” an stabilization error in one of my videos using the scale and rotate filters and keyframe editing. However, whatever export option I chose, I now always get an progressive output file with 25p instead of 50i.
I know that scaling filters need deinterlacing before being applied to interlace video material, but when I select interlace output, I assume that the affected parts of the video would be re-interlaced after internal composition, while the scenes, where the scaling filters are not applied, are output “1:1”.
Any hints what could have went wrong in my setup?
If this is a limitation of Shotcut (found a hint saying “use filters in shortcut for automatic deinterlacing”), I would regard this being a bug because I am not used to get progressive output (with half frame rate) when I select “interlaced” in the output settings or doubled frames when selecting progressive output with the frame rate set to 50p.
Thanks in advance for any answer!