What you're describing has been done for years by Kodi, Plex, Emby and other media front-ends. I am sure you are aware of this software. When you rip something, you end up with a computer file. If you name that file accordingly (e.g. Movie (2018)), the media front-end will pull up the title, various artwork, cast and crew information and technical information from sites such as IMDb and The Movie Database. This recreates the experience of having the disc and player with even greater immersion due to the added artwork and movie wall browsing for all titles in your collection -- not just the single disc in the player. So this is similar to how you would browse content in Netflix.
This is one example of a skin in Kodi: https://www.youtube.com/watch?v=HbwG7ZuBrDU
There are a few steps involved...
1. You must rip your media
For 1080p content, this is easy. You can buy any Blu-ray drive (preferably, one without riplock) and use ripping software such as MakeMKV or AnyDVD HD to make a 1:1 digital copy. Then it is just a matter of sitting through the process of ripping each disc and naming the resulting file with the appropriate naming conventions. The two most common ripping formats are ISO and MKV. ISO retains the movie extras with the ability to use menus with some software, while MKV contains only the main title and appropriate audio and subtitle tracks. MKVs are supported by all media players and reduce file sizes by a considerable amount, so it is the more popular format.
4K UHD content has made the ripping process more complicated. To hack AACS 2.x, you need a specific type of Blu-ray drive with specific firmware. This is detailed in the first post of this thread.
You must purchase a "friendly" Blu-ray drive and flash its firmware to an older version to get it to read UHD discs. Flashing the firmware is a fairly involved process and requires direct access to your motherboard to connect the Blu-ray drive. If you are not very technical, this may seem imposing, but it can be done if you buy the right drive and follow the instructions linked in post one. The most popular software for ripping 4K UHD media are MakeMKV and DeUHD, among others listed in the first post. There is still security built-into AACS 2.x that hasn't been enabled yet. So it is possible to lose the ability to rip new 4K UHD media in the future. But that hasn't been an issue so far through the first two layers of AACS 2.x protection. AACS 1.0 (1080p Blu-ray) has no such restrictions.
2. You need a server to store your media
Sitting through the process of ripping and renaming your media is tedious if you have a large collection. Once you have ripped something, you need some place to store it. Given you are using a projector, I would recommend a separate "ripping" station with access to a NAS box with several hard drive bays or a PC with a case and motherboard capable of supporting many mechanical hard drives. It is an option to use RAID software to manage hard drive space and deal with the possibility of failed drives. RAID use will increase the amount of drives you need, however. You will need a lot of storage, as Blu-ray rips are huge digital files: Think 12TB or more of usable drive space, especially when UHD rips can exceed 50GB each. Investing in a bunch of large TB hard drives is something you need to consider when building a server for your collection.
3. You need a client/player
To play content from the server on your projector, a front-end with a 4K HDR media player is required:
- Nvidia Shield (Kodi and Plex. Not great at upscaling and average image quality. Issues with color space conversions);
- Apple TV 4K (Kodi fork (MrMC) and Plex. Can't do TrueHD Atmos or DTS:X and converts all HD audio to PCM. Better image quality and upscaling than the Shield, but not high-end. Supports Dolby Vision through MrMC with ISO rips);
- Dedicated Kodi Boxes
(Limited to Kodi with similar upscaling and image quality to the Apple TV 4K but with support for HD audio);
- Windows HTPC
The Windows HTPC is what you're inquiring about. There are some caveats to this approach: You are running a full PC operating system, so expect to use a keyboard and mouse on many occasions. You will likely have to deal with bugs and issues caused by Windows Updates and new GPU drivers. If you don't like to tinker with Windows, you may not like owning a HTPC. You should be technical and comfortable in using Windows. Automation with a Harmony remote or an iPad with iRule is possible, and this is how you would interact with the HTPC on most occasions. But do know that you'll have to deal with Windows fairly frequently, so a mouse and keyboard is necessary.
As for the benefits of madVR, there are several. Good HDR tone mapping for projectors is available with a fair amount of customization. This is actually being improved at this moment. Color accuracy and upscaling quality are very good and comparable to the best Blu-ray players out there. Calibration via a 3D LUT should strongly be considered and is easy to accomplish in madVR. I can't say there are many advantages to frame rate handling. Matching frame rates is still the best way to get smooth motion, and all of the options above will do that. Smooth motion is offered, but it is designed to eliminate 3:2 pulldown judder, not to improve the playback of matched frame rates. There are other options such as the Smooth Video Project (SVP)
if you want true frame interpolation for 24p sources. Many media players that use madVR can be configured to use SVP.
madVR is always a great option for getting accurate colors to the display with good upscaling quality. The growing list of its HDR options is also appealing. But you have to be willing to live with the constant tinkering and hassles of running a media front-end over Windows. It is not even close to as simple as living with a basic streaming box. So there is some sacrifice.
Before you get this far, you must figure out if you can build the server necessary to store all of your discs and you need to find a "friendly" UHD Blu-ray drive, flash the firmware and get it to recognize both your 1080p and 4K UHD discs. The ripping process requires a lot of patience and file renaming. Only then can you worry about a client player to play this media. There should always be a client out there that can play your collection, so you don't have to commit to anything immediately. You must first determine if you are capable of accessing the necessary drives and software to rip everything. Again, refer to post one for some instruction.
I hope that answered most of your questions