I've been struggling with a slow computer and want to build a new rig for just capturing and encoding video files, Mainly lossless AVI SD but encoding can be HD 3:4.

I'm thinking of getting AMD Ryzen 7 3800XT 8-Core 3.9 GHz Socket AM4 to build on a Mini ITX motherboard a few TB's hard drive and a 32 or 64GB RAM, My budget limit for the complete build excluding the monitor which I already have is not to exceed $1000, Any recommendation for the motherboard and case? Is the above spec adequate enough for such a task?