Image and video scalability in the compressed domain.

Image and video compression is becoming increasingly popular with the advent of broadband networks, high powered workstations, and compression standards. Compared to the traditional spatial domain techniques, the compressed domain techniques in a reduced computational complexity and storage requirements. In addition, significant processing speedup may be gained because of the lower data rate in the compressed domain. In this thesis, we have proposed two novel techniques, namely format compatible (FC) DCT and format modified (FM) DCT to implement image/video spatial scalability by operating directly on the DCT compressed data. The FC-DCT technique can be used to manipulate the standard bit streams, which maintains the formats of the processed bit streams. We have implemented the JPEG DCT domain hierarchical mode encoder based on the FC-DCT technique. On the other hand, the FM-DCT technique is simpler and has a significantly lower computational complexity. Hence, the FC-DCT and FM-DCT techniques can be chosen based on the specific needs of the applications. We note that the FC-DCT and FM-DCT techniques are not directly applicable for manipulations of video data due to the requirement of motion estimation/compensation procedure in addition to DCT coding. Hence, we propose a macroblock type selective (MTS) encoder to implement scalable MPEG video coding using a combined FC-DCT and modified DCT domain motion compensation technique. The proposed encoder provides an elegant way to re-encode the scaled video while maintaining a good video quality. In addition. it is compatible with the standard MPEG encoder. (Abstract shortened by UMI.