Multiple Synchronized Video Streams on IP Network

Abstract: Video surveillance today can look very different depending on the objective and on the location where it is used. Some applications need a high image resolution and frame rate to carefully analyze the vision of a camera, while other applications could use a poorer resolution and a lower frame rate to achieve it's goals. The communication between a camera and an observer depends much on the distance between them and on the contents. If the observer is far away the information will reach the observer with delay, and if the medium carrying the information is unreliable the observer has to have this in mind. Lost information might not be acceptable for some applications, and some applications might not need it's information instantly. In this master thesis, IP network communication for an automatic tolling station has been simulated where several video streams from different sources have to be synchronized. The quality of the images and the frame rate are both very important in these types of surveillance, where simultaneously exposed images are processed together. The report includes short descriptions of some networking protocols, and descriptions of two implementations based on the protocols. The implementations were done in C++ using the basic socket API to evaluate the network communication. Two communication methods were used in the implementations, where the idea was to push or to poll images. To simulate the tolling station and create a network with several nodes a number of Raspberry Pis were used to execute the implementations. The report also includes a discussion about how and which video/image compression algorithms the system might benefit of. The results of the network communication evaluation shows that the communication should be done using a pushing implementation rather than a polling implementation. A polling method is needed when the transportation medium is unreliable, but the network components were able to handle the amount of simultaneous sent information very well without control logic in the application.