template<class T> static void safe_aligned_reallocz(T *&ptr, size_t old_size size_t new_size) {
    void *newalloc = av_mallocz(size);
    if (newalloc) {
        memcpy(ptr, newalloc, min(old_size, new_size));
    }
    av_free(ptr);
    ptr = static_cast<T*>(newalloc);
}