The new formula is just the inverse function of the CFR part of
the TimeAtFrame function.
To see how the previous implementation was faulty, see either the added
tests, or
- In Aegisub, open a dummy video with a frame rate of 23.976
- Make a subtitle event with start time 04:44.41
- Double-click the line to (supposedly) seek to its first frame
- This will seek one frame earlier than it should, and the event will
not be displayed on the resulting frame.
These were giving false negatives on samba shares, which broke the font
collector. Windows also recommends to not use access checks in these
cases, and instead just see if the operations succeeds or not.
The previous logic wouldn't compile on linux using clang.
With the meson build requiring c++14, there's no need for platform
specific code. Really, the entire agi::util::sleep_for function could be
removed entirely, but I'll keep the patch minimal for now.
Meson port instead of using CMake as I ran into issues with the
src directory (where uchardet.h is located) not being appended
to the include path, and on Windows I ran into a Meson issue
where a -D macro definition was being interpreted as a filename.
In the end a Meson port seemed simpler than working out the CMake
issues, as the CMakeLists.txt files were straightforward and easy
to port.
Note that because of the directory structure of the uchardet source
I had to change the include directive from uchardet/uchardet.h
to just uchardet.h. This is actually more in line with the uchardet
pkg-config file, which appends /usr/include/uchardet to the include path.
uchardet will report that a file is "ascii" if the first page has no bytes
>127, so we need to actually look at the entire file in case the first higher
byte is later in the file.
$(subst .c,.o,...) replaces '.c' with '.o' everywhere in pathnames. For
example, renaming the "Aegisub" folder to "Aegisub.cool" will make the
build system generate "Aegisub.oool/.../.o" objects.
https://www.gnu.org/software/make/manual/make.html#Text-Functions
