merge - How does one programmatically mix multiple audio tracks into one track?

Question

What is the algorithm used by Audacity (or any other audio editing program) to mix separate sound tracks?

ie. what is the process of merging the tracks to a single one when the "Mix and Render" command is used.

Answer 1

信号を追加するだけです。

// fill the destination (output) with the sum of signals: input1, input2, input3
for (size_t idx(0); idx < samplesToWrite; ++idx) {
    output[idx] = input1[idx] + input2[idx] + input3[idx];
}

ボリュームまたはパンニングを信号に適用するには、乗算を使用します。

// to halve the amplitude of an audio signal:
const double halfVolume = 0.5;
for (size_t idx(0); idx < samplesToWrite; ++idx) {
    signal[idx] *= halfVolume;
}