how long does it take for videos to upload to a shared album?

Is the Photos app trying to download everything from iCloud to upload everything again to that shared album?!

Is that the way iCloud Shared albums work?

Yes, that is necessary. The file size for Shared albums is limited. To add photos and videos to a shared album, Photos will create image files with a pixel size of at most 2048 pixels at the longest edge. So it needs to download the full sized originals from iCloud to create the new images for the shared album. Videos will be converted to a resolution of up to 720 pixels. iCloud Photo Sharing - Apple Support

File types that you can use in iCloud Photo Sharing

iCloud Photo Sharing supports HEIF, JPEG, RAW, PNG, GIF, TIFF, and MP4, as well as special formats you capture with your iPhone, like slo-mo, time-lapse, 4K videos, and Live Photos. You can even share your Memory videos. When shared, photos taken with standard point-and-shoot cameras, SLR cameras, or iOS devices have up to 2048 pixels on the long edge. Panoramic photos can be up to 5400 pixels wide.

iCloud Photo Sharing supports HEVC, MP4, and QuickTime video file types, and H.264 and MPEG-4 Video file formats. Videos can be up to five minutes in length and are delivered at up to 720p resolution. You can even share GIFs that are 100MB or smaller.

Also, Shared Albums are using a different section of iCloud and do not count against your iCloud storage.

I was on the phone with Apple support this morning and they confirmed it.

But léonie, you do see my point, right?

The photos are already on iCloud. It makes no sense what so ever, for the app to re-download everything and uploaded again.

I do know (now) and realize Shared Albums are using a different section of iCloud, but it's still everything within iCloud.

Every iCloud sub-section is in the iCloud space/bubble/house/section.

It could make sense if, a photo or video was not in the supported format of Album Sharing, for it to download, convert and upload (only) those files.

The rest is already there. It's just a matter of iCloud mirroring the file location.

There's no other cloud system out there, surely not any of the big boys, that uses this method.

Glad we're on the subject.

I've just upgraded my iCloud account to 2tb. After one week, I managed to upload my whole photo library to iCloud (~300gb).

I have my iCloud account shared with my sister and was trying out the shared albuns.

I tried to create an album of a trip we made, selected all the photos and videos and added them to that Shared Album I created. (I'm doing this on the Photos app on my Mac and I have the Optimize Mac Storage turned on).

I then noticed that it was "Downloading 3300 items to be shared".

Is the Photos app trying to download everything from iCloud to upload everything again to that shared album?!

Is that the way iCloud Shared albums work?

Yes, I see that this is a wasteful, additional network traffic.

It could make sense if, a photo or video was not in the supported format of Album Sharing, for it to download, convert and upload (only) those files.

But the videos need to be converted to a lesser resolution, so they are downloaded from iCloud to be converted to the supported, reduced size.

And anyway, the downsized videos and photos from the shared albums will be stored locally on your Mac, not only in iCloud. They will take up additional storage on your Mac.

How long is a piece of string?

There is no possible way to answer since there are too many unknown variables - basically the answer is as long as it takes - you can no speed it up but you can delay it - keep the Mac powered, awake and on the internet

And as a suggestion in the future do smaller steps - 67 videos, even short ones, is a massive amount of data and will take a long time -- Patience is a virtue, give it time and do not mess around with the porcess

LN