[opus] Aborting on NaN in CELT - what are the conditions for crash in transient_analysis

[Alexandr Petak]

Hello,
in this commit in celt_encoder.c
https://git.xiph.org/?p=opus.git;a=commitdiff;h=652c4559f593d3aad78bd5c85a216eeae7859429

I see the note:
+      /* We should never see NaNs here. If we find any, then
something really bad happened and we better abort
+         before it does any damage later on. If these asserts are
disabled (no hardening), then the table
+         lookup a few lines below (id = ...) is likely to crash dur
to an out-of-bounds read. DO NOT FIX
+         that crash on NaN since it could result in a worse issue later on. */

I think I'm exactly in that situation. Opus codec crashes occasionally for
me with Access violation in the transient_analysis function on the line
where it's computing the id from the floating point.

 id = (int)MAX32(0,MIN32(127,floor(64*norm*(tmp[i]+EPSILON))));

Could you please provide more info about what could be the crash reason
there?

Regards,
Alex
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