I have applied through a recruiter. The first Skype meeting was organized shortly, because "the position had to be filled ASAP". The meeting was about 40 minutes long with a short job introduction and some general questions.
After the first Skype meeting I was asked to do a test assignment - to write a stereo matching solver for calculating dense disparity map between one stereo pair of images (the images were provided and had an abnormally large baseline). The solver must be written in C++ and optimized for multi-core architecture. In addition, 3 different evaluation approaches must be also implemented and tested. It was also forbidden using existing libraries for the solver implementation. They gave 2 weeks for accomplishing the task (with possibility of prolongation till 4 weeks on request).
I have developed a similar stereo matching solver during my master work at University, so it took me only 10 days to accomplish the task and submit my solution. We agreed to have another Skype meeting to discuss it.
During the second meeting, the interviewer said that they are impressed with my solution and there were no certain issues to discuss. They also said that they contact me within a 2 weeks period and discuss the next steps.
After that, they just disappeared. I never was asked to do such massive test assignments and got a feeling that the firm just delicates some tasks to applicants for a fake position. I regret that I spend a lot of time for the test assignment and got no feedback from the company.