[FFmpeg-devel] [PATCH] QCELP decoder postfilter & final gain control

Måns Rullgård mans
Sun Apr 12 18:19:55 CEST 2009

"Reynaldo H. Verdejo Pinochet" <reynaldo at opendot.cl> writes:

> Hello
> M?ns Rullg?rd wrote
>> If filter_coeffs is pointing to the first element of an array, that
>> subtraction *is* invalid.
> That's what I tried to argue yesterday's night at IRC but Baptiste
> said (he might clarify this if he's reading) it wont matter as long
> as the code itself isn't reading nor writing from there. I personally
> don't like the 'trick' and I'm not sure its even guaranteed to work but
> whenever I'm not sure I ask, and it being a 'non issue' has been the
> answer so far.

Merely calculating an address outside an array or dynamically
allocated block might cause an overflow trap or similar.  I have seen
this happen in a real system, and it was not easy to track it down.

M?ns Rullg?rd
mans at mansr.com

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