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