Remove Interlacing

Interlacing often exists on older video sources, such as camcorders, and was previously used in broadcast television. Playing this video results in jagged images on a computer monitor, but with CINELERRA-GG you can use deinterlacing effects to solve this. After some experimentation, it has been determined that the FFmpeg F_kerndeint plugin seems to produce the best results with the least amount of fiddling. But some of the parameters described next are pertinent to other potential plugin usage.

Line Doubling:
done by the Deinterlace effect when set to Odd lines or Even lines. When applied to a track it reduces the vertical resolution by ${\frac{{1}}{{2}}}$ and gives you progressive frames with stairstepping. This is only useful when followed by a scale effect which reduces the image to half its size.
Line averaging:
the Deinterlace effect when set to Average even lines or Average odd lines does exactly what line doubling does except instead of making straight copies of the lines, it makes averages of the lines. This is actually useful for all scaling.
Inverse Telecine:
this is the most effective deinterlacing tool when the footage is an NTSC TV broadcast of a film. It is described in Effect Plugins (10.10.43).
Time base correction:
the previously discussed three tools either destroy footage irreversibly or do not work at times. Time base correction may be a better tool to use because it leaves the footage intact. It does not reduce resolution, perceptually at least, and does not cause jittery timing.
Frames to Fields effect:
converts each frame to two frames, so it must be used on a timeline whose project frame rate is twice the footage's frame rate. In the first frame it puts a line-averaged copy of the even lines. In the second frame it puts a line-averaged copy of the odd lines. When played back at full framerate it gives the illusion of progressive video with no loss of detail. This effect can be reversed with the Fields to Frames effect, which combines two frames of footage back into the one original interlaced frame at half the framerate. However, keep in mind that Frames to Fields inputs frames at half the framerate as the project. Effects before Frames to Fields process at the reduced framerate. The output of Frames to Fields can not be compressed as efficiently as the original because it introduces vertical twitter and a super high framerate. Interlaced 29.97 fps footage can be made to look like film by applying Frames to Fields and then reducing the project frame rate of the resulting 59.94 fps footage to 23.97 fps. This produces no timing jitter and the occasional odd field gives the illusion of more detail than there would be if you just line averaged the original. It is described in Effect Plugins (10.10.32).
HDTV exceptions:
1920×1080 HDTV is encoded in a special way. If it is a broadcast of original HDTV film, an inverse telecine works. But if it is a rebroadcast of a 720×480 source, you need to use a time base and line doubling algorithm to deinterlace it.

The CINELERRA-GG Community, 2021