pub unsafe extern "C" fn av_buffer_pool_init2(
size: usize,
opaque: *mut c_void,
alloc: Option<unsafe extern "C" fn(opaque: *mut c_void, size: usize) -> *mut AVBufferRef>,
pool_free: Option<unsafe extern "C" fn(opaque: *mut c_void)>,
) -> *mut AVBufferPool