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Rate distortion optimized multipass video encoding for H.264/AVC

: Mohammed, H.M.; Färber, N.; Thoma, H.

He, Y.:
25th Picture Coding Symposium 2006. Proceedings. Vol. 2 : 24 - 26 April 2006, Beijing, China
Beijing, 2006
Picture Coding Symposium (PCS) <25, 2006, Beijing>
Fraunhofer IIS ()
Algorithmus; Berechnungskomplexität; experimentelles Ergebnis; Kostenfunktion; Optimierungsalgorithmus; optisches Bauelement; Problemlösung; SNR=Signal-Rausch-Verhältnis; Übertragungsrate; Vektorquantisierung; Verzerrung; Videocodierung

In this paper we describe the application of a rate-distortion optimized multipass (RDM) algorithm to the encoding of H.264/AVC video. The RDM algorithm addresses the problem of dependent quantization in a hybrid coding framework by constructing a trellis from the exponentially growing search tree which is then searched using a Lagrangian cost function. To avoid exponential growth, states with similarly distorted reference frames are merged based on the assumption that similar rate-distortion behavior will result for future frames. The goal is to select an optimal quantizer for each frame such that the overall R-D performance is optimized. The paper addresses the issues of complexity reduction and rate control, which are important for the application in practice. Experimental results obtained with H.264/AVC show an average gain of l dB PSNR compared to a single pass rate control while limiting the complexity increase to a factor of 4. The proposed rate control achieves the target bit rate within a margin of 0.1 %.