> You can now do C:ffmpeg.exe -i D:scene1.mp4 output-scene1.mp4

This won't actually work because multiple current directories are a fiction of cmd.exe

Interestingly, this blog post says it is implemented in the Win32 and kernel API (in RtlGetFullPathName) and thus should also work outside of cmd.exe: <https://projectzero.google/2016/02/the-definitive-guide-on-w...>

A “fiction” implemented as environment variables, which the ffmpeg process would inherit, so there's nothing stopping ffmpeg from “indulging the fiction”. Depending on how frequently users expect this behavior to work, I might even call it a bug in ffmpeg (or whatever file handling library it relies on) that isn't even all that hard to fix.