MixAudio

AviSynth+
Up-to-date documentation: https://avisynthplus.readthedocs.io

MixAudio(clip clip1, clip clip2, float clip1_factor, float clip2_factor)

Mixes audio from two clips. A volume factor for the two clips can be given, but is optional.

clip  clip1, clip2 =

Source clips. Output video is copied from clip1.

float  clip1_factor, clip2_factor = (auto)

Set the volume of each clip's audio, where 0.0 is no audio from that clip, and 1.0 is 100% audio.

Default is 0.5/0.5; if only one factor is given, the other will be 1.0-(factor).

If clip1_factor+clip2_factor > 1.0, you risk clipping your signal if sample type is not Float.

The sample rate of the two clips needs to be the same – use ResampleAudio if necessary.

Your clips need to have the same number of channels – use ConvertToMono, MonoToStereo or MergeChannels if necessary.

Example:

# mixes two sources, with one source slightly lower than the other.
video = AviSource("c:\movie.avi")
Soundtrack = WavSource("c:\soundtrack.wav")
Speak = WavSource("c:\speak.wav")
audio = MixAudio(Soundtrack, Speak, 0.75, 0.25)  
# (the Expert may notice that the last 0.25 is actually redundant here)
return AudioDub(video, audio)