Need help from youtube-dl/ffmpeg expert

[MeckiMesser]

I downloaded a vr video from Youtube using youtube-dl.
But the video is not as expected. I guess there is a problem with youtube-dl or ffmpeg downloading vr material.
See my post regarding my problem here in the forum:
https://forum.videohelp.com/threads/392980-youtube-download-vr-videos-with-one-stream-...l-split-inside

I think the problem is caused by me, handling youtube-dl and/or ffmpeg without using the necessary parameters/configuration.
Is here any experienced user who can help?

Regards

[pandy]

But the video is not as expected.

What do you expecting from video?

[MeckiMesser]

I expect that download is a vr (virtual reality 360°) video.
VR video has special format, distorded in high and width.
But has no horizontal split.
The download from youtube-dl is a wrong composition of video elements.

I guess the video is a composition of 4 x 90° components (equivalent to 4 cameras used ??)
(like hvq mentioned, potplayer shows 4 interactive angles).
And youtube-dl can't build this in a correct way.
But why?

[pandy]

Combination of crop and stack (overlay) can be used in ffmpeg to modify video in desired way.

[MeckiMesser]

The video downloaded is definitely composed in this way by youtube-dl, because I switched off the use of ffmpeg and got the same download.
Maybe I can use ffmpeg to repair the video.

[pandy]

The video downloaded is definitely composed in this way by youtube-dl, because I switched off the use of ffmpeg and got the same download.
Maybe I can use ffmpeg to repair the video.

Would try to find information on format - Google should have description somewhere - have no time currently to dig internet - try to do some research on this, if you find something please provide links.

---
Seem this is new VR format called Equi-Angular Cubemaps
https://blog.google/products/google-ar-vr/bringing-pixels-front-and-center-vr-video/
https://code.fb.com/virtual-reality/next-generation-video-encoding-techniques-for-360-video-and-vr/

Seem facebook created ffmpeg filter (afraid it need to be added to special ffmpeg build)
https://github.com/facebook/transform360

this topic may be beneficial too
https://github.com/ytdl-org/youtube-dl/issues/15267

[richardpl]

Facebook filter does not support youtube's vr format as input.
There is plan to have native ffmpeg filter doing such conversion(s).

[MeckiMesser]

The easiest way to get correct format is to use --user-agent "" for download,
then the video was downloaded in equirectangular panorama format from youtube.

Thanks to Pandy for it's great work.