Information Technology Reference
In-Depth Information
One important aspect of this cross layer design is that the information of depth is
also considered for the prioritization process. The distortion cost for an object that is
farther from the camera or the viewing point in a video scene is adjusted according to
its depth value. This allows prioritization of packets that are closer to the viewing point
as they are assumed to contribute more to the perceived visual quality.
In the home entertainment scenario, the transcoder receives three segmented,
encoded video streams. The transcoder also receives feedback from the WLAN
transmitter about the channel conditions. The function of transcoder is to tune the
data rate of the three streams based upon the channel condition. It changes the
quality of the video by selecting the appropriate QP value from the available QP-
distortion set table. This table information is received by the transcoder in the
form of signaling form the source provider. The transcoder operates at the com-
pressed domain level to avoid excessive complexity burden as suggested in [27].
Existing transcoders can modify the QP with very minor degradation in quality
compared to directly compressing the video at the modified QP.
Fig. 4
Schematic diagram of the proposed cross layer multimedia transmission system for
the home entertainment environment
