Package: swh-plugins
Version: 0.4.17-2+fh1
Severity: important
Tags: upstream patch
mbeq_1197.xml:
float coefs[FFT_LENGTH / 2];
[...]
coefs[0] = 0.0f;
for (bin=1; bin < (FFT_LENGTH/2-1); bin++) {
coefs[bin] = ((1.0f-bin_delta[bin]) * gains[bin_base[bin]])
+ (bin_delta[bin] * gains[bin_base[bin]+1]);
}
[...]
for (i = 1; i < FFT_LENGTH/2; i++) {
comp[i] *= coefs[i];
comp[FFT_LENGTH-i] *= coefs[i];
}
The first loop leaves coefs[FFT_LENGTH/2-1] uninitialized because it
only runs while bin < FFT_LENGTH/2-1.
The second loop reads from coefs[FFT_LENGTH/2-1], boom!
With some bad luck (which I had, of course, and of course only in
hard to reproduce circumstances) the uninitialized value will be NaN
which due to the FFT poisons the whole output with NaN.
Fix (note the "-1" is not needed at all. Maybe someone thought so
because of the "+1" in the line below, but that doesn't apply to bin
at all):
--- mbeq_1197.xml
+++ mbeq_1197.xml
@@ -140,7 +140,7 @@
// Calculate coefficients for each bin of FFT
coefs[0] = 0.0f;
-for (bin=1; bin < (FFT_LENGTH/2-1); bin++) {
+for (bin=1; bin < (FFT_LENGTH/2); bin++) {
coefs[bin] = ((1.0f-bin_delta[bin]) * gains[bin_base[bin]])
+ (bin_delta[bin] * gains[bin_base[bin]+1]);
}
-- System Information:
Debian Release: 11.2
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500,
'stable-debug'), (500, 'proposed-updates-debug'), (500, 'proposed-updates'),
(500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-9-amd64 (SMP w/24 CPU threads)
Locale: LANG=de_DE, LC_CTYPE=de_DE (charmap=ISO-8859-1), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages swh-plugins depends on:
ii libc6 2.31-13+deb11u2
ii libfftw3-single3 3.3.8-2
ii libgsm1 1.0.18-2
swh-plugins recommends no packages.
swh-plugins suggests no packages.
-- no debconf information
