vector<float> process_frame(unsigned frame_num, AudioMixer *mixer)
{
duration<int64_t, ratio<NUM_SAMPLES, OUTPUT_FREQUENCY>> frame_duration(frame_num);
vector<float> process_frame(unsigned frame_num, AudioMixer *mixer)
{
duration<int64_t, ratio<NUM_SAMPLES, OUTPUT_FREQUENCY>> frame_duration(frame_num);