Patent ID: 9729888
Date: 2017-08-08
CPC Classifications: H04N

Claim:
1. A method of selecting a video coding mode and a quantization parameter for an image coding unit to be coded and quantized in an image coding process, comprising: taking a video stream as input; selecting, for the video stream, an initial quantization parameter and a best coding mode for the initial quantization parameter; evaluating coding modes for subsequent quantization parameters in accordance with a coding mode transition state machine comprising coding mode states and transitions between coding mode states, wherein each state of the coding mode transition state machine corresponds to a coding mode and a mode transition likelihood score is assigned to the transition between a pair of coding mode states, at least one mode transition likelihood score being assigned a value based at least in part on whether the transition is from an inter coding mode to an intra coding mode or if the transition is from an intra coding mode to an inter coding mode, transitions from inter coding modes to intra coding modes being given a lower likelihood score than transitions from intra coding modes to inter coding modes; selecting an optimal coding mode and an optimal quantization parameter among the evaluated coding modes and quantization parameters, wherein the number of transitions between coding mode states is selected in accordance with a transition likelihood threshold, so that only transitions between coding modes having a transition likelihood score above the transition likelihood threshold are allowed; and encoding the video stream with the optimal coding mode and the optimal quantization parameter.