I can't help you with the video but I have just done an experiment with a photo of my cat (no human volunteers were willing). The RAW image (taken on X-Pro2 with 56mm f/1.2 at 1/250 f/2.8 ISO 500) was converted to JPEG at NR settings of -4, -2, 0, +2 and +4. The whole image is at the NR -4 setting, the 600x400px crops are at NR settings of -4, -2, 0, +2 and +4. To be honest, there really isn't much of a difference until you get to +2 and only the +4 looks bad. Hope it helps, I will try to repeat this experiment with a human face at a higher ISO.