Modified coding for a transform skipped block for CABAC in HEVC
In an example, an electronic device of a decoder is configured to obtain a bit stream and recover a binary symbol from the obtained bit stream. The electronic device is configured to determine whether the binary symbol is to be decoded using a modified transform skip mode. The electronic device is configured to, in response to determining that the binary symbol is not to be decoded using the modified transform skip mode, determine a first TS_Shift value, and recover video data using the first TS_Shift value. The electronic device is configured to, in response to determining that the binary symbol is to be decoded using the modified transform skip mode, determine a second TS_Shift value, and recover video data using the second TS_Shift value.
1. An electronic device, comprising a processor and a non-transitory computer-readable medium having processor-executable instructions stored thereon, wherein the processor-executable instructions, when executed by the processor, facilitate performance of the following:
obtaining a bit stream;
recovering a binary symbol from the obtained bit stream;
determining whether the binary symbol is to be decoded using a modified transform skip mode or a non-modified transform skip mode;
determining a TS_Shift value based on whether the binary symbol is to be decoded using the modified transform skip mode or the non-modified transform skip mode, wherein:
in response to determining that the binary symbol is to be decoded using the modified transform skip mode, the TS_Shift value is determined according to MAX[(MAX_TDR-Bit_Depth-Log 2TrSize), 0] or MAX_TDR-Bit_Depth-Log 2TrSize+A; and
in response to determining that the binary symbol is to be decoded using the non-modified transform skip mode, the TS_Shift value is determined according to MAX_TDR-Bit_Depth-Log 2TrSize;
recovering video data based on the determined TS_Shift value; and
storing the recovered video data in a memory device;
wherein Max_TDR is a maximum dynamic range of a transform, Bit_Depth is a bit depth of sample values, and Log 2TrSize is Log 2 of a transform size.
2. The electronic device according to claim 1 , wherein A is a value determined based on a signal from an encoder.
3. The electronic device according to claim 1 , wherein A is a value determined based on a property of the obtained bit stream.
4. The electronic device according to claim 1 , wherein determining the TS_Shift value according to MAX[(MAX_TDR-Bit_Depth-Log 2TrSize), 0] corresponds to the following modified inverse transform skip process:
r[x][y]=d[x][y]<<7
bdShift=(cldx==0) ? 20−BitDepth Y :20−BitDepth C
bdShift=MAX(7, bdShift)
r[x][y]=(r[x][y]+(1<<(bdShift−1)))>>bdShift
wherein x and y represent array indices for vertical and horizontal dimensions, and wherein the expression x ? y:z corresponds to the following—if x is TRUE or not equal to 0, the expression evaluates to the value of y; otherwise, the expression evaluates to the value of z.