0.71.0 Cannot compile for Android

[AdrianEddy]

Since 4a15ef2 I'm getting the following build error when trying to compile for Android (aarch64-linux-android)

error[E0308]: arguments to this function are incorrect
    --> .cargo\registry\src\github.com-1ecc6299db9ec823\opencv-0.71.0\src\opencv\hub\videoio.rs:1956:12
     |
1956 | ... { sys::cv_VideoWriter_fourcc_char_char_char_char(u8::try_from(c1)? as c_char, u8::try_from(c2)? as c_char, u8::try_from(c3)? as c_char, u8::try_from(c4)? as c_char, o...
     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ---------------------------  ---------------------------  ---------------------------  --------------------------- expected `i8`, found `u8`
     |                                                      |                            |                            |
     |                                                      |                            |                            expected `i8`, found `u8`
     |                                                      |                            expected `i8`, found `u8`
     |                                                      expected `i8`, found `u8`
     |
note: function defined here
    --> C:\Users\Eddy\.cargo\registry\src\github.com-1ecc6299db9ec823\opencv-0.71.0\src\opencv\hub\sys.rs:4229:10
     |
4229 |         pub fn cv_VideoWriter_fourcc_char_char_char_char(c1: i8, c2: i8, c3: i8, c4: i8, ocvrs_return: *mut Result<i32>);
     |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: you can convert a `u8` to an `i8` and panic if the converted value doesn't fit
     |
1956 |         unsafe { sys::cv_VideoWriter_fourcc_char_char_char_char((u8::try_from(c1)? as c_char).try_into().unwrap(), u8::try_from(c2)? as c_char, u8::try_from(c3)? as c_char, u8::try_from(c4)? as c_char, ocvrs_return.as_mut_ptr()) };
     |                                                                 +                           +++++++++++++++++++++
help: you can convert a `u8` to an `i8` and panic if the converted value doesn't fit
     |
1956 |         unsafe { sys::cv_VideoWriter_fourcc_char_char_char_char(u8::try_from(c1)? as c_char, (u8::try_from(c2)? as c_char).try_into().unwrap(), u8::try_from(c3)? as c_char, u8::try_from(c4)? as c_char, ocvrs_return.as_mut_ptr()) };
     |                                                                                              +                           +++++++++++++++++++++
help: you can convert a `u8` to an `i8` and panic if the converted value doesn't fit
     |
1956 |         unsafe { sys::cv_VideoWriter_fourcc_char_char_char_char(u8::try_from(c1)? as c_char, u8::try_from(c2)? as c_char, (u8::try_from(c3)? as c_char).try_into().unwrap(), u8::try_from(c4)? as c_char, ocvrs_return.as_mut_ptr()) };
     |                                                                                                                           +                           +++++++++++++++++++++
help: you can convert a `u8` to an `i8` and panic if the converted value doesn't fit
     |
1956 |         unsafe { sys::cv_VideoWriter_fourcc_char_char_char_char(u8::try_from(c1)? as c_char, u8::try_from(c2)? as c_char, u8::try_from(c3)? as c_char, (u8::try_from(c4)? as c_char).try_into().unwrap(), ocvrs_return.as_mut_ptr()) };
     |                                                                                                                                                        +                           +++++++++++++++++++++

0.70.0 compiles and works fine

[twistedfall]

Thanks for the report, it should be fixed in v0.72.1!

[dopaminista]

Hi could you share your env variables and give some tips about CMakeList.txt in your android project

[AdrianEddy]

What exactly do you want to know? I just used the standard env variables + prebuilt android opencv package from https://opencv.org/releases/

$Env:LIBCLANG_PATH = "$PROJECT_DIR\ext\llvm-15-win64\bin"
$Env:OPENCV_LINK_LIBS = "opencv_calib3d,opencv_features2d,opencv_imgproc,opencv_video,opencv_flann,opencv_core,tegra_hal,tbb,ittnotify,z"
$Env:OPENCV_LINK_PATHS = "$PROJECT_DIR\ext\OpenCV-android-sdk\sdk\native\staticlibs\arm64-v8a,$PROJECT_DIR\ext\OpenCV-android-sdk\sdk\native\3rdparty\libs\arm64-v8a"
$Env:OPENCV_INCLUDE_PATHS = "$PROJECT_DIR\ext\OpenCV-android-sdk\sdk\native\jni\include"