Congestion-aware transmission rate control using Medium Grain Scalability of Scalable Video Coding
In packet-oriented networks, packet losses occur mainly due to queue overflows in congested network elements. An increase of the packet rate therefore raises the likelihood of congestion and expected number of lost packets. However, an increase of the packet size has typically a negligible impact on the packet loss rate or congestion in wired packet-switched networks. Scalable Video Coding (SVC), an extension of the Advanced Video Coding (H.264/AVC), provides different types of scalability, one of which is Medium Grain Quality Scalability (MGS). When MGS is in use, layer representations can be pruned unevenly without affecting the decoding of the remaining bitstream. The article proposes a packetization algorithm to improve the quality of the reconstructed video stream while the expected packet loss rate remains unchanged compared to conventional packetization. The algorithm is based on appending MGS enhancement layer data into conventionally generated packet payloads until the Maximum Transmission Unit (MTU) is reached. The simulation results show that the proposed algorithm provides 0.3 to 0.5 dB gain in average luma Peak Signal-to-Noise Ratio when compared with a conventional packetization method while the packet rate remains unchanged.