Segfault if "output" directory doesn't exist

[ChainSwordCS]

As the title suggests. The "output" folder should be in the same directory as the executable.

If the directory doesn't already exist, it encounters a segmentation fault error and stops (instead of, say, creating the directory if it doesn't already exist).

This specifically happens in the decode_video function.

If it matters, I'm on Linux Mint 21 (based on Ubuntu 22.04), x64 architecture.