National Taiwan University

Tao-Sheng Ou

Homer H Chen

Yi-Hsin Huang

Po-Yen Su

Tsung Yau Huang

Chieh Kai Kao

The present invention is directed to a rate-distortion optimized (RDO) transform and quantization system. A frame classification unit classifies an input frame as either a key frame or a non-key frame. A rate model update unit generates at least one model parameter of a rate model according to a transform coefficient and a bitrate resulted from an encoded key frame. An RDO transform and quantization unit processes the input frame, thereby generating a quantized transform coefficient according to the model parameter. A frame buffer is used to store a previous frame, according to which the bitrate is estimated.

Method for rate-distortion optimized transform and quantization through a closed-form operation

A rate control method of perceptual-based rate-distortion (R-D) optimized bit allocation is disclosed. An input frame is firstly determined as a key frame or non-key frame. A key frame is additionally encoded to generate rate-distortion (R-D) points. The R-D model of each basic unit (BU) is updated, followed by perceptual-based bit allocation, thereby generating a target bit rate. A quantization parameter (QP) is computed according to the target bit rate, and the current BU is encoded according to the QP. A rate-quantization (R-Q) model is updated if not all BUs have been encoded.

Rate control method of perceptual-based rate-distortion optimized bit allocation

A perceptual-based video coding method provides a perceptual-based rate-distortion (R-D) curve as a predictive R-D curve. The Lagrange multiplier for a current frame is then determined by deciding a slope, with sign reversed, of a tangent to the predictive R-D curve at a current point that is on the predictive R-D curve and closest to a previous R-D point of a previous encoded frame. The current frame is then encoded according to the determined Lagrange multiplier.

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Taipei, Taiwan

Tao-Sheng Ou