This method is based on the relation between the modes of H.264/AVC, the base layer of SVC, and the enhancement layers of SVC.
It is the scalability info, a description of the enhancement layers of the video that includes the resolution of the spatial layers, the frame rate of the temporal layers, and the average bandwidth required to transmit the video up to each layer.
Scalable video coders provide different scaling options, such as temporal, spatial, and SNR scalabilities, where rate reduction by discarding enhancement layers of different scalability-type results in different kinds and/or levels of visual distortion depend on the content and bitrate.
For the enhancement layer of multicast group i, we decide its transmission rate in sub-channel l such that the enhancement layer throughput in suchannel l be maximinzed.
The panels display the frequency ranges and the spectral content of the core layer and the first enhancement layer of a scalable AAC + SBR bit stream.
Constrains (8-12) ensure that one subchannel can not be reused by a unicast traffic, the base layer of a multicast traffic, and the enhancement layer of a multicast traffic.
There-fore, we can calculate the achievable throughput of the enhancement layer of each multicast traffic and the achievable rate of each unicast traffic in each subchannel, and then allocate each subchannel to the traffic with maximum achievable throughput initally.
where ρl, uis either 1 or 0, depending on whether the subchannel l is assigned to unicast user u or not, αl, iexplains whether the subchannel l is assigned to the base layer of the i th multicast group, βl, jdenotes whether the subchannel l is assigned to the enhancement layer of the j th multicast group.
The differentiation in robustness of base and enhancement layer of the scalable media and the resulting different received qualities depending on the user's reception conditions leads to graceful degradation, which can in fact lead to higher acceptance of the service itself due to higher service availability, for some users possibly at reduced quality.
When the transmission power in each subchannel is determined, the optimal transmission rate for the enhancement layer of multicast group i in subchannel l, r l, k *, k * ∈ U i mul, is determined such that E l, i k can be maximized, i.e., k * = arg max k ∈ U i mul E l, i k.
In addition, several enhancement layers for the reconstruction of higher scalable levels of the video are encoded.
