mirror of
https://github.com/cookiengineer/audacity
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63 lines
2.2 KiB
Plaintext
63 lines
2.2 KiB
Plaintext
(SAMPLER-ALG
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(NAME "sampler")
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(ARGUMENTS ("sound_type" "s") ("double" "step") ("double" "loop_start")
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("rate_type" "sr") ("double" "hz") ("time_type" "t0")
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("sound_type" "s_fm") ("long" "npoints"))
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(TABLE "s")
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(NOT-IN-INNER-LOOP "s")
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(STATE
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("double" "loop_to" "loop_start * s->sr")
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("table_type" "the_table" "sound_to_table(s)")
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("sample_type *" "table_ptr" "susp->the_table->samples")
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("double" "table_len" "susp->the_table->length;")
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("double" "phase" "0.0")
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("double" "ph_incr" "(s->sr / sr) * hz / step_to_hz(step);
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s_fm->scale = (sample_type) (s_fm->scale * (susp->ph_incr / hz));
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/* make sure parameters are ok
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* the table must have samples
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* the loop_start must be before the end of the table
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* ph_incr must be positive
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* sr should be positive
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*/
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{ long index = (long) susp->loop_to;
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double frac = susp->loop_to - index;
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if (susp->the_table->length <= 1) {
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xlfail(\"sampler table length <= 1\");
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}
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if (index > round(susp->table_len) - 2 ||
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index < 0) {
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xlfail(\"sampler loop start not within samples\");
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}
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if (susp->ph_incr <= 0) {
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xlfail(\"sampler phase increment <= 0\");
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}
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if (sr <= 0) {
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xlfail(\"sampler sample rate <= 0\");
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}
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/* copy interpolated start to last entry */
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susp->table_ptr[round(susp->table_len)] =
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(sample_type) (susp->table_ptr[index] * (1.0 - frac) +
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susp->table_ptr[index + 1] * frac);}")
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)
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(ALWAYS-SCALE s_fm)
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(STEP-FUNCTION s_fm)
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(TERMINATE (MIN s_fm))
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(LOGICAL-STOP (MIN s_fm))
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(INNER-LOOP-LOCALS " long table_index;
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double x1;
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")
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(INNER-LOOP "table_index = (long) phase;
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x1 = table_ptr[table_index];
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output = (sample_type) (x1 + (phase - table_index) *
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(table_ptr[table_index + 1] - x1));
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phase += ph_incr + s_fm;
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while (phase > table_len) phase -= (table_len - loop_to);
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/* watch out for negative frequencies! */
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if (phase < 0) phase = 0")
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(CONSTANT "ph_incr" "table_len" "table_ptr" "loop_to")
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(SAMPLE-RATE "sr")
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(FINALIZATION " table_unref(susp->the_table);\n")
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)
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