Why videos in low light take more space in videos in daytime?

285 views

I’ve observed this in many phones over the years, and it seems like videos in low light take more space than those with more light. One would think that due to the detail loss in the low light, the videos would take less space. Why isn’t that the case?

In: 2

2 Answers

Anonymous 0 Comments

Low light requires high ISO, basically turning the video amplifier up to max, and this causes video noise. That shows up as random grain-like effects in the images, with pixels randomly brighter or darker than their neighbours.

And randomness is the enemy of compression; much of image compression relies on most pixels being the same as their neighbours, and video compression relies on one frame being largely the same as the preceding and following frames. The very randomness of noise means it takes more bytes to encode in compressed formats.

You are viewing 1 out of 2 answers, click here to view all answers.