Wagging the Dog: Effects of Hyperoptimal Youtube Upload Bitrates

Musicvid wrote on 12/15/2018, 7:03 PM

Pretty simple stuff, but this colorful theory has shown up on the forum three times in as many weeks.

Source: 2160 50p 4k

Download: 2160 50p 4k

Upload Format: x264 two-pass

Download format (VP9 4k, original quality)

Recommended Youtube upload bitrate: 60 Mbps

And now I've got a link to point them to, which will never get clicked.

I call it a good Saturday evening.




john_dennis wrote on 12/15/2018, 11:44 PM

"You can check out any time you want, but you can never leave."

john_dennis wrote on 12/16/2018, 12:57 AM

The problem with the fixed sized pipe that you expose is that different content requires different bit rates to make things work. Here is an experiment that I did to illustrate the bit rate requirement for different content.

The first example is what I'll call the walking, talking heads (a stage play, not a song and dance musical).

  • Locked-down camera.
  • One or two people on a stage strolling and talking.
  • Not all of the frame moving or even illuminated. 

The second example is a sporting event.

  • Camera continuously panning to follow the subject.
  • The subject(s) are moving body parts.
  • The water around the subject is being disturbed and is in constant motion.

I rendered one minute from two different sources that meet those descriptions from the same project to the same Custom Command Line in the Happy Otter Scripts. Doing so allowed me to use an encoder that encodes to a Constant Rate Factor. In this case I chose CRF=20. Everything in the project and the encode is the same except for the nature of the content. Here are the results:


The high motion sports content required 51.6% more bits/pixel*frame than the low motion stage play. Which one do you think is going to look worse when it's bit rate is constrained by youtube?

Musicvid wrote on 12/16/2018, 9:23 AM

The one with the most complexity and worst lighting?

Knew you couldn't stay away from this, j_d. I think the rest were watching WWF