Rate control for region of interest video coding in H.264

Includes bibliographical references (pages 45-46).The Rate Control module in the reference video codec software Joint Model (JM), developed by Joint Video Team (JVT) of H.264/AVC video coding standard, is responsible for assigning bits to each coding unit such that the available bit budget is efficiently utilized. Different parameters are considered to assign a Quantization Parameter (QP) and hence have a check over the number of bits allocated to a coding unit (16x16 macroblock, unless partitioned). The flexible macroblock ordering (FMO) feature in H.264/AVC enables customized ordering of the macroblocks for the encoding. This thesis implements an algorithm by combining the rate control scheme and the FMO feature to selectively enhance the quality of Regions of Interest (ROI) in a video frame which is called the ROI video coding. Such kind of video coding is particularly helpful in applications like video conferencing or transportation of surveillance videos over wireless channels. These applications require video encoding schemes which exploit the fact that the entire frame is not important and hence different parts of the frame should/can be encoded with varying qualities. ROI coding is to be enabled by making appropriate changes in the rate control module to accommodate some regions in a frame with relatively higher importance. The algorithm employs FMO Type 2 which is meant to divide macroblocks into foreground and background regions in a frame. The coordinates for the ROI comes from a tracking algorithm and is updated for every frame. Later the macroblocks in the non-ROI/background (region other than the ROI) slice group are assigned a relatively higher QP. Then the bits allocated for the frame is divided in a manner aiding this disproportionate QP assignment within a fram