Crop Clarification

[Ryushin]

I'm getting mixed messages if I need to use cropping or not. This is coming from this thread

Essentially I re-encoded all my UHD disc sources into a HDR10 MKV files with the letterbox cropped out (top and bottom for widescreen and sides for 4:3 sources like Snyder's Justice League). I now want to re-rip all my DV UHD discs using MakeMKV into a MKV file and then extract the DV RPU.bin file and inject it into my cropped encodings.

Since I'm seeing conflicting information, do I use cropping option in the dovi_tool from the source that does have letterbox, to inject into my encoding that has been cropped to remove the letterbox. Thanks much for creating this tool.

[quietvoid]

My suggested workflow is as follows:

• Extract RPU from source with mode 0, to validate the parsing is correct.
• Edit the RPU according to the output/final video needs, using the editor subcommand.
• Use the RPU with x265, or if that's not possible (i.e encoding with FFmpeg directly) then using the injector for the final video.

For cropping, I did post a pretty clear explanation before here: https://forum.doom9.org/showpost.php?p=1951422&postcount=33

Source video 2160p with letterbox bars:

encoded as 2160p with letterbox bars: don't use crop. encoded as 2160p and cropped (no more letterbox bars): use crop. encoded as 1080p with letterbox bars: you need to edit the active area to set the final letterbox bars size as offsets, see documentation. encoded as 1080p and cropped: use crop.

So with the editor workflow, an example for UHD disc profile 7 to profile 8.1 encode, where you have cropped all the letterbox bars:

{
    "mode": 2,
    "active_area": {
      "crop": true
    }
}

In the end, it is usually pretty safe to use --crop all the time as well.

[Ryushin]

Thank you. So the crop command pretty much works the way one logically would expect it to. If I'm encoding a source and I'm cropping it, extract the DV source with the crop command and then inject it into the cropped encoded video.