Improved H.264/AVC Requantization Transcoding using Low-Complexity Interpolation Filters for 1/4-Pixel Motion Compensation

Transcoding is a fast technique for video adaptation, which offers great flexibility for changing the characteristics of already coded video sequences in order to match the properties of the terminal display devices and the bandwidth availability of the transmission networks. For reduction of the bitrate, requantization transcoding is often used. In our previous work, we introduced a hybrid architecture for requantization transcoding, which is able to reduce the bitrate for H.264/AVC bitstreams with quality results approaching the rate-distortion optimal decoder-encoder cascade. In this paper, we focus on the filters used for interpolation of the accumulated requantization errors, which are used for compensation of the current (sub-)macroblock partition. We show that by using reduced complexity filters, computational complexity can be significantly reduced without quality loss