Is there any where you might point me to to learn further about these terms? ABR, CRF or CQ(P).
I recommend Werner Robitza's Understanding Rate Control Modes (x264, x265, vpx) article for a quick-ish rundown.
Using H.264, H.265, and VP8/9 codec specs for reference...
Average Bit Rate (ABR)
A.K.A Target Bitrate
Like the other modes you mentioned, this is a variable bit rate (VBR) mode.
If you have time to kill and you want to maximize quality, you can also employ 2-pass encoding. This pre-analyzes footage to find the best way to quantize and store its data.
This mode indirectly controls quality, is often paired with an optional Max Bit Rate, and has no minimum bit rate. As Vouk said, setting this parameter is the best for outputting to a certain file size.
Resolution, color bit depth, and frame rate are the most important factors when considering video bit rate. Consider the duration/length as well when you want a specific file size.
Constant Rate Factor (CRF)
Control the bit rate to achieve a specified visual quality. This is rather self-explanatory, but be warned that it may remove small details that it believes are unwanted artifacts. Note: Lower number == higher quality.
Constant Quantization Parameter (CQP)
This is a more literal "constant quality" mode. It is generally not recommended because CRF does the same thing, but with better quality and file sizes.
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Whenever I have a question about a particular codec's parameters, I tend to turn to its documentation within FFMpeg's documentation and, of course, search engines.