Printing to 1080p dimensions

On the Print page, in Page Setup, we have a wide selection of page sizes. I’d like to be able to export to 1080p resolution (1920 x 1080 at 72dpi) for the purposes of making videos. I can’t easily figure out how to add new presets for page sizes. I checked Setup’s Layout Options, and converted to mm (508 x 266mm), but can’t quite figure out how to apply that to my score, so I can export to 1080p.

(Feature request: 1080p and 4k should be standard included output presets for the modern era.)

If you are exporting Normal jobs (as opposed to booklets, 2Ups etc.), the only page size that matters is the one in Layout Options. Ignore what the print preview shows, and ignore the dropdown in the right panel of Print mode.

Ultimately, until such time as they implement a video export feature, you need to create a new layout to the dimensions that you want, or just scale your pages in your video editor.

You want to make score videos? Here are approaches for different operating systems.

macOS Catalina:
There should be a hotkey that allows you to videotape the entire or a part of your screen with choosable audio input. You may use either virtural system-wide audio bus driver (like Soundflower or blackhole, available on GitHub) or hardware loopback functionality provided by your audio interface to bridge Dorico audio output into the videotape recording process.

Here comes an example of what I videotaped on my computer (my composition):

Windows:
Even though non-LTSB/LTSC releases of Windows 10 have XBox Gaming functionality to help you videotape any Windows application, its audio and video quality may not meet your needs (looks more terrible and takes much bigger file sizes comparing to what can be done on macOS). Considering purchasing a Bandicamp license and using Bandicamp to capture the desktop. In this case, a good NVidia video card helps Bandicamp to videotape the screen in a more stable way without overloading the CPU. Regarding how to capture the audio at the same time, I am afraid that you have only hardware approaches (like what I mentioned above for macOS, e.g.: ZOOM UAC-2 supports hardware loopback) because software approaches cannot capture ASIO audio streams (unless you let Dorico to use ASIO-to-WASAPI adapter drivers like Steinberg GLL driver, FL Studio ASIO Driver, etc.). Nevertheless, it is sophisticate on WIndows.

P.S.: LTSB / LTSC releases of Windows 10 have no XBox Gaming functionalities, but there are approaches to get them installed.

Thanks all, and to @ShikiSuen. I was going to use ScreenFlow to make the videos. But what I really wanted was for Dorico to format the pages to fit within 1920x1080px at 72dpi, in other words, really maximize that space. That’s why I asked for a “page size” for that resolution.

Be careful with screenflow; you’ll have to use image formats, not PDFs. It doesn’t properly display PDFs (or rather, it limits your ability to zoom in on a document while animating it and it is rasterized). I use camtasia to animate my scores and it actually uses the vector shapes of PDFs which is much better.

I would rather suggest Johntt to export SVG formats and make the animation in Macromedia Flash 8 (or MX) or similar software vector-based animation software.
https://archive.org/details/vintagesoftware?and[]=Macromedia+FLash+MX

P.S.: Do not use Adobe Flash (maybe name changed) unless you either own it or have Adobe CC subscription. Adobe Flash is hardware-performance-consuming.