19:28:59.849: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 756 (6.7%)
You are experiencing GPU rendering lag. I see you got a good GTX 1070 GPU so that shouldn't be the reason why you are experiencing rendering lag playing Minecraft Java. If you haven't updated your drivers recently, go and do so with
GeForce Experience.
19:28:59.850: Video stopped, number of skipped frames due to encoding lag: 757/11351 (6.7%)
19:20:16.827: CPU Name: Intel(R) Core(TM) i7-5930K CPU @ 3.50GHz
You are getting encoding lag playing Minecraft and recording. An i7-5930K is an ok CPU. However, I notice it is a "K" that can be overclocked. Are you overclocking the CPU? Don't. It is not worth the extra 5-6% increase in performance. If the CPU is being over taxed, you will get throttling that can screw up your recordings. Go back to BIOS defaults.
19:25:50.637: [ffmpeg muxer: 'adv_file_output'] Writing file 'C:/Users/porku/Videos/2020-06-03 19-25-50.mkv'...
19:28:59.849: [ffmpeg muxer: 'adv_file_output'] Output of file 'C:/Users/porku/Videos/2020-06-03 19-25-50.mkv' stopped
Just an observation since the observations above are just guesswork. Is your C: drive nearly full? Not disk optimized? Highly fragmented?
Get a PC cleaner like CCleaner or Glary Utilities and get rid of crap. Run it everyday.
Run Windows Optimize Drives on the C: drive (only if its a SATA drive).
If your boot C is still close to full after doing all of this, then go out and install another drive to record to.
Outside this, I don't see any obvious problems from a quick look through your log.
