Non-Transform Coding

Abstract

Techniques for selectively transforming one or more coding units when coding video content are described herein. The techniques may include determining whether or not to transform a particular coding unit. The determination may be based on a difference in pixel values of the particular coding unit and/or one or more predefined rate-distortion constraints. When it is determined to not perform a transform, the particular coding unit may be coded without transforming the particular coding unit.

What is claimed is: 
     
         1 . A method comprising:
 under control of an encoder of a computing device configured with computer-executable instructions:
 dividing a video frame into multiple coding units; 
 determining that one or more criteria are satisfied related to a particular coding unit of the multiple coding units; 
 performing intra-frame prediction on the particular coding unit to generate residual information; and 
 based at least in part on determining that the one or more criteria are satisfied, generating a bitstream at least partly from the residual information without transforming the residual information. 
   
     
     
         2 . The method of  claim 1 , wherein the determining that the one or more criteria are satisfied includes determining that a difference between the highest pixel values and the lowest pixel values of the coding unit is above a predetermined value, determining that one or more predefined rate-distortion constraints are satisfied, or determining that the particular coding unit would be associated with more than a predetermined number of non-zero quantized coefficients if the particular coding unit were transformed and quantized. 
     
     
         3 . The method of  claim 1 , wherein the generating the bitstream includes:
 quantizing the residual information;   entropy coding the quantized residual information.   
     
     
         4 . The method of  claim 3 , further comprising:
 reconstructing the particular coding unit from the quantized residual information without inverse transforming the residual information; and   utilizing the reconstructed coding unit to encode another coding unit of the multiple coding units.   
     
     
         5 . A system comprising:
 one or more processors; and   memory, communicatively coupled to the one or more processors, storing computer readable instructions that, when executed by the one or more processors, cause the one or more processors to perform acts comprising:
 determining to refrain from transforming or inverse transforming a particular unit of a video frame; and 
 based at least in part on determining to refrain from transforming or inverse transforming the particular unit of the video frame, coding the particular unit through intra-frame prediction while refraining from transforming or inverse transforming the particular unit. 
   
     
     
         6 . The system of  claim 5 , wherein the coding comprises entropy coding the particular unit based at least in part on previous units that are coded without transforming the previous units. 
     
     
         7 . The system of  claim 5 , wherein the particular unit comprises a coding unit defined by the High Efficiency Video Coding standard. 
     
     
         8 . The system of  claim 5 , wherein the particular unit comprises a non-split transform unit. 
     
     
         9 . The system of  claim 5 , wherein the coding includes refraining from applying a de-blocking filter to the particular unit. 
     
     
         10 . The system of  claim 5 , wherein the determining to refrain from transforming the particular unit includes determining that a difference between the highest pixel values and the lowest pixel values of the particular unit is above a predetermined value, determining that one or more predefined rate-distortion constraints are satisfied, or determining that the particular unit would be associated with more than a predetermined number of non-zero quantized coefficients if the particular unit were transformed and quantized. 
     
     
         11 . The system of  claim 5 , wherein the transforming comprises performing a discrete cosine transform or a discrete wavelet transform on residual information associated with the particular unit. 
     
     
         12 . The system of  claim 5 , wherein the acts are performed by an encoder. 
     
     
         13 . The system of  claim 5 , wherein the acts are performed by a decoder. 
     
     
         14 . One or more computer-readable storage media storing computer-readable instructions that, when executed, instruct one or more processors to perform operations comprising:
 determining to refrain from transforming a coding unit associated with a video frame;   performing intra-frame prediction on the coding unit to generate residual information; and   based at least in part on determining to refrain from transforming the coding unit, quantizing the residual information without transforming the residual information.   
     
     
         15 . The one or more computer-readable storage media of  claim 14 , wherein the operations further comprise:
 based at least in part on determining to refrain from transforming the coding unit, refraining from applying a de-blocking filter to the coding unit.   
     
     
         16 . The one or more computer-readable storage media of  claim 14 , wherein the operations further comprise:
 generating a bitstream from the quantized residual information, the bitstream including a flag indicating that the coding unit was coded without transforming the residual information.   
     
     
         17 . The one or more computer-readable storage media of  claim 14 , further comprising:
 entropy coding the quantized residual information based at least in part on previous coding units that are quantized without transforming the previous coding units.   
     
     
         18 . The one or more computer-readable storage media of  claim 14 , wherein the determining to refrain from transforming the coding unit includes determining that a difference between the highest pixel values and the lowest pixel values of the coding unit is above a predetermined value, determining that one or more predefined rate-distortion constraints are satisfied, or determining that the coding unit would be associated with more than a predetermined number of non-zero quantized coefficients if the coding unit were transformed and quantized. 
     
     
         19 . The one or more computer-readable storage media of  claim 14 , wherein the coding unit is defined by the High Efficiency Video Coding standard. 
     
     
         20 . The one or more computer-readable storage media of  claim 14 , wherein the operations further comprise:
 reconstructing the coding unit from the quantized residual information without inverse transforming the residual information; and   utilizing the reconstructed coding unit to encode another coding unit.