Title :
Leveraging the quantization offset for improved requantization transcoding of H.264/AVC video
Author :
Notebaert, Stijn ; Cock, Jan De ; Vermeirsch, Kenneth ; Lambert, Peter ; De Walle, Rik Van
Author_Institution :
Dept. of Electron. & Inf. Syst., Ghent Univ., Ghent, Belgium
Abstract :
Requantization transcoding is a method for reducing the bit rate of compressed video bitstreams. Most research on requantization is concerned with the architectural design, the selection of a suitable quantizer, or the reduction of requantization errors. In this paper, we propose to incorporate a new dimension in requantization transcoding: the quantization offset. We compare two requantization methods: increasing the quantization step size and decreasing the quantization offset. Furthermore, we propose a novel heuristic for requantization transcoding based on a theoretical rate-distortion analysis. The experimental results for H.264/AVC video show that requantization is improved in rate-distortion sense with gains up to 1 dB for open-loop requantization of B pictures compared to requantization with fixed quantization offset.
Keywords :
data compression; quantisation (signal); rate distortion theory; transcoding; video coding; H.264/AVC video; bit rate reduction; compressed video bitstream; improved requantization transcoding; open-loop requantization; quantization offset; theoretical rate-distortion analysis; Automatic voltage control; Image coding; Image reconstruction; Laplace equations; Quantization; Rate-distortion; Streaming media; Transcoding; Transform coding; Video compression; H.264/AVC; requantization; signal processing; transcoding;
Conference_Titel :
Picture Coding Symposium, 2009. PCS 2009
Conference_Location :
Chicago, IL
Print_ISBN :
978-1-4244-4593-6
Electronic_ISBN :
978-1-4244-4594-3
DOI :
10.1109/PCS.2009.5167466