Real-time video coding/decoding
View Patent ↗A video codec having a modular structure for encoding/decoding a digitized sequence of video frames in a multi-core system is described. The video codec comprises a memory unit; a multithreading engine. and a plurality of control and task modules organized in a tree structure, each module corresponding to a coding operation. The modules communicate with each other by control messages and shared memory. The control modules control all coding logic and workflow, and lower level task modules perform tasks and provide calculations upon receiving messages from the control task modules. The multithreading engine maintains context of each task and assigns at least one core to each task for execution. The method of coding/decoding comprises an error resilient algorithm.
1. A method of encoding/decoding a digitized sequence of video frames in a multi-core system, the method comprising:
encoding the sequence of video frames by performing core motion estimation and weighted texture prediction; and
decoding encoded sequence of video frames using high motion update and low motion update for error resilience;
wherein the error resilience comprises:
defining each macroblock as a high motion macroblock or a low motion macroblock;
defining for each macroblock of a current frame a set of macroblocks including the macroblock of the current frame and at least one macroblock located at the same position in previous frames; and
making a choice between INTRA and INTER coding mode for each macroblock of high motion update frame and each macroblock of low motion update frame;
wherein the choice between INTRA and INTER coding mode for the error resilience is based on the following:
the INTRA coding mode is used for high motion update frames, when
cost_intra·K H <cost_inter, and
set C(D) contains at least one high motion macroblock; and
the INTRA coding mode is used for low motion update frames, when
cost_intra·K L <cost_inter, and
set C(T L ) contains at least one high or low motion macroblock;
where
K H —INTRA cost scaling factor for high motion frames;
K L —INTRA cost scaling factor for low motion frames;
T H —high motion INTRA update period;
T L —low motion INTRA update period; and
D—high motion INTRA update depth.
2. The method of encoding/decoding of claim 1 , wherein a macroblock is defined as a high motion macroblock, when
S>=MVT H , and
SD>=MVTD H ; and
a macroblock is defined as a low motion macroblock, when
MVT L <=S<MVT H , and
MVTD L <=SD<MVTD H ,
where
S is a sum of absolute values of motion vector components of the macroblock;
SD is a sum of absolute values of motion vector prediction difference components of the macroblock;
MVT H is a high motion threshold for the sum of absolute values of the motion vector components;
MVTD H is a high motion threshold for the sum of absolute values of the motion vector prediction difference components;
MVT L is a low motion threshold for the sum of absolute values of the motion vector components; and
MVTD L is a low motion threshold for the sum of absolute values of the motion vector prediction difference components.