(Click to enlarge)
You'll notice that Dog Run had to be repeated since it was much shorter than the others. There are some other things worth mentioning:
- The spikes in the blue BarScene graph are scene changes; therefore an encoder could, on the first pass, detect scene changes for keyframe purposes using a standard deviation threshold value.
- At nearly 100% entropy, snow is obviously not going to survive lossy compression very well. Its high standard deviation would also prompt the encoder to make every frame a keyframe. This would be a major problem unless you had good "hard" rate control.
Here's the BarScene graph, which has the most distinct activity.
I found Ronald Bultje's "Overview of the VP9 video codec" very helpful. I'm close to fully understanding the VP9 bitstream and once I do, I'll be able to start my actual encoding experiments.