#746 Unable to create DVD with interlaced video properly

[jan-adam]

The most important thing when creating a DVD is to maintain the time resolution. This is very important because the progressive formats of 50 fps and 59.94 fps are deliberately chosen to record, for example, sports and other events with fast action or things that need to have a "live look". Also, all currently used downscaling methods to old SD formats (for example for satellite broadcasting) will preserve the time resolution:

50 fps progressive -> 25 fps INTERLACED (50 fields per second)
59.94 fps progressive -> 29.97 fps INTERLACED (59.94 fields per second)

Unfortunately, DVDStyler works completely wrong here. I added a 4K 50 fps video to the project, and with the default settings the output DVD was 25 progressive. Totally wrong.

I've tried changing the title settings (three dots, video properties, target format: interlaced instead of progressive), but the output DVD still looks bad. The output is 25 fps wrapped in interlacing.

Then I started messing around with the ffmpeg command line. And the bug is probably here. You need to add an additional filter to make ffmpeg convert 50 fps to interlaced 25 fps correctly (and similarly 59.94 fps to interlaced 29.97 fps).

A quick and dirty solution is to insert the "interlace" video filter somewhere at the beginning of the command line. Another requirement: after scaling. The ffmpeg-vbr.bat file is very complicated, I didn't know where to put it.

For testing, I inserted this:

-filter✌️0 scale=720:576,interlace

right below the ":NoFix" label, on the first line, between "-c✌️0 mpeg2video" and "-dc 10"

And voila! Now the DVD looks correct and we have a smooth 50 fps (25 fps with true interlacing).

The "interlace" filter has a built-in low-pass filter to avoid twitter and moire artifacts. Just use this filter (for 720x576 video, not original size!) and the progressive 50 fps will turn into smooth interlaced video.

TODO for the owner of DVD Styler:

• Fix the described bug, e.g., by adding an interlace filter.
• Consider all cases. I tested and described a quick and dirty solution for CBR mode. However, the fix should also be applied to other modes, such as two-pass.
• Additionally, for 50 and 59.94 fps video, DVDStyler SHOULD automatically set the output to interlaced instead of progressive

[jan-adam]

Sorry, the editor automatically created the emoji. It should be:

-filter:v:0 scale=720:576,interlace

between

 -c:v:0 mpeg2video   and   -dc 10