Questions about archiving my video files

[Bahamuth]

Hello everyone,

after being absent for a long time, I thought, when I can get some good answers for my encoding questions, it might be here.

First I want to say, that there are surely many many threads about similar questions inside here, but I hope, my questions might be more current / better solved with more current versions of x264.

First my specifications:
CPU: Intel i7-3770s @3,9GHz
RAM: 16 GB
GPU: NVidia GeForce GTX 980
OS: Windows 7 Professional 64 bit
Software: StaxRip

Video sources I want to (re)encode:
DVD: MPEG2 720x576/540 (Amount: >200 DVDs)
BluRay: VC1/H264/MPEG2 1920x1080 (Amount: >30 BluRays)
Others: various formats with various resolutions, going down to 100x100 pixel (Amount: at least several hundreds I want to archive, some with rather old codecs like Duck TrueMotion)

What I want to achieve:
Encoding the various videos into a (mostly) single video format, placing them on my NAS. File size most probably isn't a problem (20 TB space), so I'm trying to achieve quality videos (yet I'd like not to have BluRays with 25 GB but maybe 10 or less after reencoding).

My questions:
x264 or x265?
I've read quite some sites and found various comments. Some say, x265 is better for streaming and x264 is better for archiving. Then again they say, x265 is better for videos in lower resolution. Considering my sources, which format should I choose? The input videos will have material of all kinds (real life, CGI, animations). Somewhere I've read, that starting from around 2500kbit/s x264 and x265 make a significant less difference in encoding.

CPU (x264/x265) or GPU (NVEnc)?
Should I encode with my CPU (which, depending on the quality settings, might be rather slow) or on my GPU (which runs like ten times faster)? Most comments I've read about this have stated, that NVEnc is better for streaming e.g. game play and such. Of course GPU runs faster, but it looks like the quality isn't close to the one via CPU encoded x264.

Encoding mode?
Which encoding mode should I use to achieve a suitable good quality to file size ratio? CBR with a specific bitrate per medium (e.g. 2500kbit for DVD, higher for BluRay etc.), VBR, CQ? Single Pass, Two Pass, Triple Pass?
I know that depending on the encoding mode, the encoding time will raise significantly.

Cropping black borders?
Something I have to admit I don't have looked up in the internet yet. Is it good or bad cropping away the black borders from a video? Does it even make the file any smaller? After all there always would be the same color, which should make it easy to be encoded as the pixels never will change during the whole video length. Or is it a bad idea when thinking about subtitles? But aren't they placed from the software? Let's say I crop a video from 720x576 to 720x500. When activating subtitles, the software most probably will place the subtitles beneath the video anyway, if I would watch the video in full screen, that is.

MKV or MP4?
More a less important question. Should I use MKV container or MP4 container? I'm used to work with MKVToolNix. Mp4ToolBox is something unknown for me.


I do my best to answer any questions which probably will follow.