I'll take you through how to replicate the paint stroke effect in After Effects, as briefly as I am able. The artwork would have to be created seperately.
Hold tight, because this guide assumes you have some basic knowledge of After Effects.
I've broken it up into three parts. The paint stroke, the brush texture and putting it all together.
1. The paint stroke
Firstly, I scoured Google for a 'free brush stroke texture' and found this:

I then searched for 'free paint splatter texture' and found this:

- Bring these images into After Effects
- Create large compostion at 3840 x 1080. Name it 'Paint stroke'.
- Use two copies of the brush stroke texture and scale them up and stretch them in the X direction, so that they create one long stripe across the screen.
- Use two copies of the splatter image and scale and rotate them until you like how it looks.
- Add a white solid to behind everything.
- Add an adjustment layer above all others and add a 'Levels' effect to it.
- Drag the lefthand slider until your blacks are nice and dark.
- Select all layers and precompose them by hitting control (command on Mac) + Shift + c. Name the layer 'Paint stroke matte'.
- Add another copy of the white solid layer below the precomp layer.
- Set it's track matte value to 'Luma Inverted Matte'. (This will set the whites of the layer above to transparent.)

- You can add a 'Fill' effect to the white solid layer to control the colour.
Here what mine ended up looking like (Fill set to red colour and black is transparent):

2. Brush texture
- Create a new composition, sized 1920 x 1080 and name it 'Brush'
- Use the pen tool to create a shape layer that looks something like this:

- Add a 'fast box blur' effect and set the blur radius to 120.
- Create a new solid layer above and add a 'Fractal Noise' effect.
- Set the contrast to 350 and then unfold the Transform section.
- Click off 'Uniform Scaling' and set the Scale Width to 5000 and the Scale Height to 15.
- Prcompose this layer and name it 'Brush Map', then turn off its visibility.
- Add an adjustment layer between the two layers and add a 'Displacement Map' effect. Set the Displacement Map Layer to the Brush Map layer and set the Max Horiz Dist to 350 and the Max Vert Dist to 0.
- Select all layers and precompose them (Ctrl/Cmd + Shift + D). Name it 'Brush Texture'.
- Add another solid layer below the texture layer and set its Track Matte value to 'Alpha Matte'.
- Add an adjustment layer to the top and add a 'Roughen Edges' effect and set its scale to 25 (the effect scale, not the layer scale).
Hopefully now it looks something like this:

- Create another large comp at 3840 x 1080 and name it 'Brush on matte'.
- Drag in the 'Brush' composition, then add another solid (make sure it is 3840 x 1080 size).
- Set the solid layer's scale to 120, then drag it so the right side of the layer just covers the right side of the Brush Layer.

- Parent the solid layer to the Brush layer.
- Keyframe the X-position of the Brush layer so that it goes from completely off screen on the left to completely covering the screen on the right over about half a second (or however long you want it to take). Should look something like this:

3. Putting it all together (Almost there)
- Add the 'Paint stroke' layer and the 'Brush on matte' to a 3840 x 1080 composition. Make sure they are in the same position and that the matte layer is on top. Name the comp 'Paint on'
- Parent the 'Brush on matte' layer to the 'Paint Stroke' layer, then set it's scale to [100, 60] (60% on Y only).
- Set the 'Paint stroke' layer's Track matte to 'Alpha Matte'
- Create one last 1920 x 1080 comp and add as many 'Paint on' comps as you want. Position, rotate and scale, until you are happy with the effect.
Here was my final product. Hope this helps someone.
