[Mp4-tech] FGS code in microsoft-v2.5-040207-NTU

[ChengHsin Hsu]

Hi All,
Just started reading the fgs code in microsoft-v2.5-040207-NTU. I  
noticed both the encoder/decoder explicitly ignore two of the least  
significant bitplanes. Tried to find any comments in txt files, but  
failed. There is an in-line comment saying this is a fix of a encoder  
bug.
Is there any particular reason of doing this? I did a quick  
experimentation, putting these two bps can give me several dB gain in  
terms of PSNR.
Any hints are highly appreciated.
Thanks,
Chenghsin