[Mp4-tech] H.264 doubts

[Alexis Michael Tourapis]

Dear Prabhakar,
please check start_macroblock() in macroblock.c
img->block_x and img->block_y correspond to the 4x4 block coordinates within a picture.  That is the entire picture is separated into 4x4 blocks and each one of them is given an (x,y)  index.  Note also that the img->block_$  parameters are set to the coordinates of the first 4x4 block within a macroblock, while inside the code, local block_$ parameters are used to access all other 4x4 blocks within the same macroblock.
img->pic_$ correspond to the actual luma pixel position/coordinates of the current Macroblock (i.e. the pixel corresponding to the top-left pixel of the macroblock).
img->pic_$_c correspond to the actual chroma pixel position of the current macroblock.
I hope this helps.
Alexis
> Hello Experts,
> 
>        I am working on the JVT9.2 decoder. I have certain doubts in code..
> 
>     What exactly the variables 
> "block_x","block_y","pix_x","pix_y","pix_c_x","pix_c_y" represents. With 
> respect to a frame, what exactly these variables  indicates.
> 
> Thanks in advance.
> 
> Regards
> Prabhakar
> 
> _________________________________________________________________
> 65,000 jobs listings. http://www.naukri.com/tieups/tieups.php?othersrcp=534 
> Post your CV on Naukri.com today.
> 
> _______________________________________________
> NOTE: Please use clear subject lines for your posts. Include [audio, [video], 
> [systems], [general] or another apppropriate identifier to indicate the type of 
> question you have.
> 
> Note: Conduct on the mailing list is subject to the Antitrust guidelines found 
> at http://www.mpegif.org/public/documents/vault/mp-out-30042-Antitrust.php