Created attachment 88 [details]
reproducer

gigextract ~/libgig-gigextract-LoadSamples-segfault-001.riff foo
Extracting samples from "/home/hsalo/libgig-gigextract-LoadSamples-segfault-001.riff" to directory "foo/".
Seeking for available samples...ASAN:SIGSEGV
=================================================================
==8764==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f6141d4e6c0 sp 0x7fffc7905cf0 bp 0x7fffc7905d40 T0)
    #0 0x7f6141d4e6bf in gig::File::LoadGroups() /home/hsalo/src/libgig/src/gig.cpp:6196
    #1 0x7f6141d622ab in gig::File::LoadSamples(RIFF::progress_t*) /home/hsalo/src/libgig/src/gig.cpp:5658
    #2 0x7f6141d4f8cc in gig::File::GetFirstSample(RIFF::progress_t*) /home/hsalo/src/libgig/src/gig.cpp:5564
    #3 0x409c38 in ExtractSamples(gig::File*, char*, std::map<unsigned int, bool, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, bool> > >*) /home/hsalo/src/libgig/src/tools/gigextract.cpp:212
    #4 0x403579 in main /home/hsalo/src/libgig/src/tools/gigextract.cpp:162
    #5 0x7f6140c18b44 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b44)
    #6 0x404029 (/home/hsalo/builds/libgig/2017-10-16/bin/gigextract+0x404029)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/hsalo/src/libgig/src/gig.cpp:6196 gig::File::LoadGroups()
==8764==ABORTING