[XviD-devel] [BUG] Pink Frames (still lacks fix)

[Edouard Gomez]

Hello,

Sorry for posting this bug again  but i think it's rather important to
fix it very soon. I'll try to explain why.

First, the bug report :

When i use a bframe build, with these parameters :

init.cpu_flags = 0
param.max_bframes = 0 or -1
frame.motion  = 0
frame.general =	XVID_MPEGQUANT or XVIDH263QUANT

i get lot of pink MBs. The pink MBs seem to appear randomly but that's
not true. In my opinion the red and blue dc coefficients are saturated
by  a bug in  the bitstream  writer or  a MB  coding bug  (remainder :
blue+red give pink :-) because pink MBs have an pink average color and
the dc coefficient is the average chroma value of MB so...

Now the most obvious and weird thing. When i use a nobframe build then
i cannot  reproduce the  bug. This  means the bug  is somewhere  in an
#ifdef  BFRAMES  block  that  breaks  the  bitstream.   I've  got  the
bitstream  specs not  so long  ago so  it's very  difficult for  me to
localize  the  problem.  It  would  take less  if  time  someone  more
experienced in the bitstream format look at this closely.

Why it's important to fix it soon :

GNU/Linux users will use the latest snapshot and for realtime encoding
most  of  them  will  use  no  halfpel in  order  ton  increase  their
framerate. Releasing a  bitsream broken snapshot is not  so good for a
project that aims to be a standard compliant codec ;-)

The  same warning  applies to  win32 users  with vfw  build on  top of
lastest snapshot.

regards

-- 
Edouard Gomez