Extracting DCT coefficents from HEVC bitstream

Question

Can anyone share any code, or functions that can be called to extract transform coefficients (DCT/DST) from HEVC bitstream?

I have checked the source code of HM 16.0. The file \\source\\Lib\\TLibCommon\\TComTrQuant.cpp is responsible for transform and quantization.
However, the function xTr which performs the DCT transform is never called in the source code. Also, fastForwardDst function performs DST on Luma intrapredicted 4x4 block, outputs 0 which is being stored in the array 'coeff'.

I am not sure how to go about this.
Any help will be appreciated. Thanks!

Answer 1

What you are trying to do seems correct to me: tracking xTr function to get pcCoeff array.

But I'd strongly suggest that you go to the decoder side and perform the same tracking. Of course, there you'll be dealing with invTr function instead of xTr (I'm not sure about the name though).

You really need to do this instead of the encoder side tracking. Because the RDO loops of the encoder makes everything overcomplicated.