I had an idea to add texts for string but don't know how to calculate it for unsigned char*.

Is the size for const char* the same as const unsigned char*?

const std::string prores_ks_trellis_node_comp_glsl = "....";
const unsigned char* ff_prores_ks_trellis_node_comp_spv_data = reinterpret_cast(std::u8string(prores_ks_trellis_node_comp_glsl.begin(), prores_ks_trellis_node_comp_glsl.end()).data());
size_t ff_prores_ks_trellis_node_comp_spv_len = std::ssize(prores_ks_trellis_node_comp_glsl);