[pkg-mad-maintainers] Bug#881283: Bug#881283: libmad0: produces different results on s390x/arm64/...

[Kurt Roeckx]

On Thu, Nov 09, 2017 at 05:23:56PM +0100, IOhannes m zmoelnig wrote:
> The problem is a failing test when decoding mp3 files.
[...]
> and the attached minimal MP3-file "sine.mp3" i get different results for s390x
> (zelenka.debian.org) and amd64 (my laptop):
> 
> s390x = [  0,   1,   0,   1, 255, 254, 255, 254, 255, 252, 255, 252, 0, 5, ...
> amd64 = [252, 255, 252, 255, 254, 255, 254, 255,   0,   0,   0,   0, 1, 0, ...

So I want to clarify this a little. Is the reason for failing that
the results are not identical, but still produce an output that contains
a sine, just a little bit different?

Since this is a fixed point implementation, and you have a build
that's limited to 32 bit, it's sort of expected that it doesn't
produce the same results, and it's clearly a tradeoff between
quality and speed. And I'm not sure which is prefered on some of
those architectures.


Kurt