Network architecture¶

• Frame format

The application foreseen aims at transmitting video streams, so we choose to use the MPEG-4/H264 coding standard, and the adapted codec x264 for video compression/decompression. The associated frame format MP4 is used for the encapsulation of multimedia data type. As a result of this encapsulation, we will transmit longer frames, containing not only data bits, but encaplsulation bits (header, footer...). Therefore, we must consider a higher bit rate than the effective video bit rate.

• Protocol stack

We define here a first sketch for the protocol stack that would best fit this application:

- Transport layer: the transmission content is video stream, and our application requires real time performance. Therefore the Real Time transport protocol (RTP) seems adapted for the project. In fact RTP adds a header to UDP packets, which specifies the transported media type and format (codec) and numbers the packets to handle losses.

- Network layer: the real time constraint also imposes to minimize the packet transmission time. The solution for that is to use UDP transport