This kind of effect can be achieved by masking and radical scaling in "y"
Put the Anchor point where you want the scaling to be centered, Duplicate the layer, Draw the mask through the anchor point (snapping helps) then scale in Y until you get the effect you want.
It looks like you could do the whole project by simply adding a bunch of layers and masks.
Yes it's exactly the same. Nothing but copies of layers masking and scaling. The key to making the edge pixels match the actual footage is having the mask precisely line up with the anchor point. If you plan a little you can even mask at an angle:
It's all about using the anchor point and a mask line to scale the pixels to get the streaks.
Rick gives you the better, more accurate solution to this, but one that would emulate the look of that video without essentially copying someone else's creative ideas would be to play around with the "block load" effect. Block Load basically reduces the resolution of your footage to varying, user specified degrees, so you can "pixelate" it in an animate-able manner. It is one of those cheesy effects that seldom gets used, but with creativity, can produce interesting results. Coincidentally, it would also be a much faster and easier way to come up with something similar to your example.
Come to think of it, I would imagine if you were to apply the Block Load, set your grid to like 10 (I don't remember if it allows you to set both width and height slices) boxes wide, then you can simply move your anchor point to the top of the frame, start your scale off at whatever number makes 1 row of "pixels" fill the frame, then slowly scale it back down to 100, while increasing your grid width until it no longer pixelates the video. This way, you don't have to make a bunch of duplicates and no masking is required.
I totally agree with you, I don't plan on replicating the video but to understand the technique used so I can better understand the types of options available on After Effects. I love the effect of block load, it's lovely.
Thank you very much for your advice!