Hello,
Sorry to hear you are having issues. Please refer to this guide on Codec: https://forums.stardock.com/485954/deskscapes-support-faq#codecs

Thanks
Basj,
Stardock Community Assistant.

Hello,
I have forward your problem/question to Stardock Support Team for their assistance. Please keep an eye on this thread for any updates. We appreciate your feedback and patience.

Basj,
Stardock Community Assistant

https://codecguide.com/download_k-lite_codec_pack_mega.htm

I use this K Lite codec  Mega pk. 

With default install.

Give it a try should fix your issue .

I am having the same problem as OP and have tried using the K-Lite Codec pack and it still won't work. I am trying to use the Stars by Neil Banfield dream and keep getting the message that I don't have the mpeg2 codec installed even though I do. I am on Windows 10 and have downloaded it from the Microsoft Store and even tried the K-Lite Codec pack and it still doesn't work.

Hi Jan, I just tried your suggestion and it didn't work unfortunately. I am not sure if the MPEG-2 codec has been installed correctly. Looking at the list of codec under System Information - Components - Multimedia - Video Codec, and I can't see any that say mpeg2 or mpg2. Unless K Lite installed it somewhere else or as part of something else.

Anyway, Deskscapes still keeps telling me I don't have it installed and so won't apply the dream. I have also noticed that Neil Banfield's Star dream is no longer available on WinCustomize so I wonder if doesn't work anymore with DS11?

It's my favourite desktop background so I'd really like to get it working again.

Hi, yes Deskscapes was already set to those settings and using EVR. It just doesn't seem to be able to find the mpeg2 codec installed on my system and so for the particular dream I am trying to use, keeps telling me I need the codec installed.

It seems to be particularly this Stars dream by Neil Banfield. I have tried some of his other dreams such as Blurry Blobs and Ovals and they work fine. I have also tried some of the stock backgrounds that come with Deskscapes such as Coloured Lights and Desktop Earth and they work fine.

I am using a fresh installation of Windows 10 (I had to reinstall due to some other issues not related) but last week when using my old installation that I had for a few years and had Deskscapes 11 and the Stars dream, it worked fine. I guess reinstalling Windows 10 and starting afresh has reset something and now either Windows is not installing the mpeg2 codec properly or for some reason Deskscapes isn't able to locate it.

Thanks very much Neil this fixed it for me, I didn't realize I didn't have any DirectX Runtime files installed and needed to get them. I absolutely love your Stars dream and use it in combination with the Rainbow effect in Deskcapes and really enjoy the colourful stars slowly moving towards me, it's very relaxing.