[XviD-devel] further quant matrix tests - libavcodec bug?

[daniel smith]

at the urging of a doom9 forum member, I did some more custom matrix tests.

after some more testing, it seems libavcodec has an "oddity" whereby if the entire custom inter matrix is set to the same value (i.e. all 16, or all 23), decoding is broken.  however changing a single matrix value from 16 to say 17 or 18 results in correct decodes.

i thought i'd post it here to see if anyone has any insights as to why this might be happening, and if it could be an xvid bug after all.  i looked through libavcodec/h263.c for a matrix loading bug, but noticed nothing out of the ordinary, so i'm assuming it's mpeg dequant at fault.

also, the all-values-of-16 files played correctly in divx5 (whee), however envivio just gave me a black screen and rmp4 contains a bug where any custom matrix is ignored.

dan

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