sampler.alg

Audacity是一款用於錄音和編輯聲音的、免費的開放源碼軟體。它可以執行於Mac OS X、Microsoft Windows、GNU/Linux和其它作業系統

(SAMPLER-ALG
(NAME "sampler")
(ARGUMENTS ("sound_type" "s") ("double" "step") ("double" "loop_start") 
        ("rate_type" "sr") ("double" "hz") ("time_type" "t0") ("sound_type" "s_fm")
        ("long" "npoints"))
(TABLE "s")
(NOT-IN-INNER-LOOP "s")
(STATE 
       ("double" "loop_to" "loop_start * s->sr")
       ("table_type" "the_table" "sound_to_table(s)")
       ("sample_type *" "table_ptr" "susp->the_table->samples")
       ("double" "table_len" "susp->the_table->length;
    { long index = (long) susp->loop_to;
      double frac = susp->loop_to - index;
      if (index > round(susp->table_len) ||
          index < 0) {
          index = 0;
          frac = 0;
      }
      susp->table_ptr[round(susp->table_len)] = /* copy interpolated start to last entry */
          (sample_type) (susp->table_ptr[index] * (1.0 - frac) + 
                         susp->table_ptr[index + 1] * frac);}")
       ("double" "phase" "0.0")
       ("double" "ph_incr" "(s->sr / sr) * hz / step_to_hz(step);
    s_fm->scale = (sample_type) (s_fm->scale * (susp->ph_incr / hz))") )

(ALWAYS-SCALE s_fm)
(INLINE-INTERPOLATION T) ; so that modulation can be low frequency
(STEP-FUNCTION s_fm)
(TERMINATE (MIN s_fm))
(LOGICAL-STOP (MIN s_fm))
(INNER-LOOP-LOCALS "	    long table_index;
            double x1;
")
(INNER-LOOP "table_index = (long) phase;
            x1 = table_ptr[table_index];
            output = (sample_type) (x1 + (phase - table_index) * 
                          (table_ptr[table_index + 1] - x1));
            phase += ph_incr + s_fm;
            while (phase > table_len) phase -= (table_len - loop_to);
            /* watch out for negative frequencies! */
            if (phase < 0) phase = 0")
(CONSTANT "ph_incr" "table_len" "table_ptr" "loop_to")

(SAMPLE-RATE "sr")
(FINALIZATION "    table_unref(susp->the_table);
")
)