[vorbis] bark_noise

Michael Smith msmith at labyrinth.net.au
Fri Nov 3 23:11:30 PST 2000



>> >At this point, noise[1]==3.4e38. We are trying to add another 3.4e38
>> >to it and this is generating a SIGFPE on my machine.
>
>I'll look at this tomorrow.  There are a number of underflows I need
>to catch for beta 3 too.
>
>(Hmm... values that negative shouldn't be popping up in bark_noise...)

Values that negative come out (again...) as a result of todB() on an argument of 0. In this particular case, it does todB(f[i]*f[i])+400. 

The +400 has essentially no effect because of the magnitude of the todB() return. Apart from that, it's being called basically directly on the transformed (MDCT) data - there's no reason why it would be bypassed here, so zeros are to be expected. 

In the bughunting earlier today I found another case where -9e38 is too negative and can cause FPEs - so it's probably best fixed just by increasing that by a few orders of magnitude.

Michael

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