[vorbis-dev] MDCT_INTEGERIZED

[Carsten Haese]

On Fri, 2004-04-09 at 08:50, Rado Buransky wrote:
> Hello,
> 
> I have used "MDCT_INTEGERIZED" version of mdct and the resulting bitstream
> is absolutely silent. Do I have to make some other changes to the source
> code to get it working? I mean some int->float or float->int conversion
> before/after call a mdct function.

When I try it, I actually get white noise. It appears that the
MDCT_INTEGERIZED code path is not fully developed, considering the
warning on the line in mdct.h that you have to un-comment to enable this
code path.

Also, when compiling with MDCT_INTEGERIZED enabled, I get compiler
warnings in mapping0.c where mdct_forward and mdct_backward are being
called. Arguments 2 and 3 in these functions are float vectors, but on
the MDCT_INTEGERIZED code path, the functions expect them to be int
vectors, and no conversion is being done.

So, if you insist on using the standard code with just the integerized
MDCT, it appears that you need some kind of float/int conversions going
into the mdct functions, and some kind of int/float conversions coming
out of them. I am wondering, though, can't you just use Tremor, the
fully integerized decoder?

-Carsten

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