[XviD-devel] direct mode predictor error

peter ross xvid-devel@xvid.org
Mon, 09 Sep 2002 22:31:43 +1000


hello,

this is more a 'todo' than a bug.
the direct-mode motion search performs a +/-16 pixel search arround
the reference block location. this is incorrect, and causes purple
(offscreen) artifacts arround the edge of the image when the motion
search is FORCED to alway use direct-mode.

i think the +/-16 search should be made arround the direct-mode
motion-vector-predictor.

also whilst browsing the REALmagic source codes, i noticed this:

// The hardware decoder is compliant to MPEG-4 definition,
// which only allows direct mode when co-located MB is not coded as INTRA

it sounds like another silly mpeg-4 limitations, like the every
132 frame i-frame rule & edged blocks must not be field-dct coded.

-- pete

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