assemble 4 1080p mkvs into a single 4k video?

[dillybacon]

does anyone know of an encoding tool that could join 4 separate 1920x1080 videos into one 3840x2160 video? i just got a 4k monitor and have been looking for sample content. one set i found for whatever reason has each 4k video broken into 4 1080p videos and i would like to stitch them back together. is there a tool for that?

thanks!

[Sparktank]

1) define "found".
2) I'm not sure how that even works.

Stitching (in Matroska terms, it usually means to linearly attach multiple sigments and treat it as a single video (with same dimensions/FPS)) multiple 1080p will not generate a 4K resolution.

Sounds like you want to piece it together like...
----------------
| A | B | C | D |
----------------
Which would give you 1080p resolutions still.

Unless you mean to re-encode them all into one new resolution (4 parts; 4 quadrants; 1 whole new resolution of 4K).
Like so....
------
| A B |
| C D |
-------

You would need to use Avisynth and reencode them.
I don't think there's a "lossless" way to do it (ie. without reencoding).

i just got a 4k monitor and have been looking for sample content.

I'm certain there's sites out there with actual 4K samples in 4K resolutions (as a whole video instead of segmented frames? How would you even describe that accurately?).
I mean, that don't require complex reassembling.

[dillybacon]

i understand what you mean but they are the official samsung 4k demos that are used in electronics stores right now. nothing shady, just decent demo material even though it is still compressed. if i run 4 instances of mpchc and put one in each quadrant of my screen, its like watching the 4k sample with boundary lines. not sure why it was broken up this way - will check out avisynth thanks

[Guest]

i understand what you mean but they are the official samsung 4k demos that are used in electronics stores right now. We need to know if they are in the public domain, so where did you get them?

[mariush]

Look up on Youtube for 4k camera reviews and footage, some are uploaded in 4k, for example :

https://www.youtube.com/watch?v=H5e-GphXgkk

https://www.youtube.com/watch?v=hEYhkvZEVN4

You can watch them on full screen straight from youtube (or save them to your computer temporarily, there's lots of ways to do that)

[awvnx]

It can be trivially done in Avisynth.

a1 = FFVideoSource("foo.mkv")
...
StackVertical(StackHorizontal(a1,a2), StackHorizontal(a3,a4))

You can run Avisynth scripts in realtime by opening them in MPC-HC, but you'll probably need a powerful CPU to do this without dropping frames.

Youtube 4K is decent at around 20 Mbps, but that bitrate is too low when closely examining the video.

If you don't mind anime sources, search for "imouto 4k". It's a short video of a 4x4 stitch, and very sharp, encoded with crf=16