Static previews broken on Windows in latest nightly

[RandomEngy]

Static previews don't show up in the 7745f42 nightly. It looks like hb_get_preview_2 is throwing an access violation exception.

I checked and all of the marshaling structs still line up exactly, so I'm not sure what this is.

[bradleysepos]

Verified.

[sr55]

Good chance it's another new mingw related issue. I'll add some logging in libhb tonight to try track it down

[bradleysepos]

I've been trying to track this down today. Seems to silently fail here on the second iteration of the loop: https://github.com/HandBrake/HandBrake/blob/master/libhb/hb.c#L692

[bradleysepos]

Update.

Our current, recently updated cross-compilation toolchain is MinGW-w64 5.0-rc2 and GCC 5.4.0. I tested MinGW-w64 4.0.6 and GCC 5.4.0, MinGW-w64 4.0.6 and GCC 4.9.2, same issue.

So, either it's something inherently wrong with how we're building the toolchain (unlikely since everything else seems to work) or it could be a problem with our upgraded pthreads-win32. Not sure why that would be the issue, but we recently discovered an issue with multi-threaded VP9 and the new toolchain also.

[bradleysepos]

I fixed the VP9 threading issue on master; unfortunately it seems unrelated to this issue.

I also tried compiling without optimizations, still fails. So it would seem some bit of our code isn't playing nice.

[bradleysepos]

@jstebbins It would be nice if you could take a look at this when you have time.

[bradleysepos]

Should be fixed in d332d4d.