[M4IF Technotes] Escape coding

[Manu V Batura]

Hi,
The MPEG-4 video standard indicates that the values 0 and 128 are reserved
while performing escape coding.
They should not be transmitted by the encoder. The decoder should also
convert a received 255 level
to 128. Can anyone please explain the reason for doing so? Which levels
should be transmitted if the levels are
0, 128 or 255 after prediction/quantization?
Thanks & Regards,
Manu