A proper Steadicam rig that can capture smooth tracking and chase shots usually requires thousands of dollars (not including the camera) and a highly-skilled operator. As a cheaper workaround, these filmmakers used a gyro-stabilised camera drone that they held in front of them like a traditional film camera.
The approach by Brazilian production house Space Criative is unorthodox, to say the least. But the results are impressive, and guerrilla filmmaking at its finest. Assuming that what we're seeing in this colour-corrected footage was actually captured by the DJI Phantom, that is.
Another advantage to this approach, as demonstrated at the end of this video, is that the shot can change from a low-angle chase to an aerial view of the action when the videographer simply lets go of the drone and lets a pilot take over.
It also poses some unique challenges. Steadicam operators rely on a strategically-positioned video monitor to show them how a shot is framed and what obstacles they might run into or step on as they move. Because the tiny cameras on drones don't have an LCD display with a live preview, the videographer here has to blindly frame a shot.
If filmed in 4K, it does result in plenty of resolution for cropping down the footage in post-production and tightening up the framing. But the results are still dependent on making sure the drone's camera is perfectly angled while it's being carried, which isn't as easy as this videographer makes it look. However, if you're on a tight budget, lots of practise will probably make this a cost-effective technique.