教程以这种方式展示，
SDL_AudioSpec wanted_spec, spec;
wanted_spec.freq = aCodecCtx->sample_rate;
wanted_spec.format = AUDIO_S16SYS;
wanted_spec.channels = aCodecCtx->channels;
wanted_spec.silence = 0;
wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
wanted_spec.callback = audio_callback;
wanted_spec.userdata = aCodecCtx;
SDL_OpenAudio(&wanted_spec, &spec);
它不起作用，显然样本是浮点，sdl音频规格格式是16位样本。如何使SDL与浮点样本一起工作？