spench.net

To more carefully study the effects of reversing motion vector directions, I created a 'control' video of me making particular motions at different speeds. You can witness the results:

The following snippet of the Burley Brawl from The Matrix: Reloaded has been passed through my hacked version of libavcodec to reverse the direction of each motion vector:

The use of motion vectors for motion compensation in video compression is ingenious - another testament to how amazing compression algorithms are. I thought it would be an interesting experiment to get into the guts of video decoder and attempt to distort the decoded motion vectors before they are actually used to move the macro-blocks (i.e. before they affect the final output frame). My motivation - more creative in nature - was to see what kinds of images would result from different types of mathematical distortion. The process would also help me better understand the lowest levels of video coding.

In the end I discovered the most unusual effects could be produced by reversing the motion vectors (multiplying their x & y components by -1). The stills and videos shown here were created using this technique. Another test I performed was forcing them all to zero (effectively turning off the motion compensation) but the images were not as 'compelling'.

Here are some stills with Neo and The Oracle conversing from The Matrix: Reloaded after the video's motion vectors have been distorted by my hacked version of libavcodec:

Inspired by a music video (which I can now no longer recall) I attempted to replicate this special effect that involves sliding the background slower than the keyed moving foreground to emphasise the motion. The two separate layers are composited as opposed to just doing a pan across the original footage. Considering I'm not using calibrated video equipment and the lighting conditions changed throughout the takes, I think the result is okay.

This is the finale of the year 2000 Prize Giving Video at my old high school. I attempted to create one of the Earth zoom-in/out sequences from scratch. They have been shown in many films, TV series and computer games. It features at the beginning of the video.

Some weekends ago I had access to a blue screen and performed a quick chroma key experiment.

Here is a neat trick you can do to make oneself see-through:

I also saw this as an opportunity to re-use an animation I created back in 2000 (it's not easy balancing your entire body on a small blue box!):

I had this idea 9 months before I saw (or even had heard of) The Matrix - you can ask my art teachers at my school!
The only difference is the shoe-string budget: that's four uncalibrated VHS video cameras and some hot air.
Check out the video, which is the result of some morphing I managed to do several years later.