[FFmpeg-user] Replacing a segment of audio

[Steve Bick]

I'm trying to replace just a segment of audio in an existing video with
another piece of audio. 

 

Goal: I have a video w/ audio, and want to replace just the audio in a
middle segment of the video without affecting the rest of the video and
audio.

 

The closest I've come is using this:

 

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ffmpeg.exe -y -i  "Video.mp4" -i "AudioToReplace.mp3" -filter_complex
"[0:a]atrim=0:316,asetpts=PTS-STARTPTS[aud1];[1:a]atrim=0:172,asetpts=PTS-ST
ARTPTS[aud2]"  -map 0:v -map "[aout]" -c:v copy -c:a libmp3lame New.mp4

-----

 

It results in the audio being replaced in the beginning of the video and the
rest of the audio shifted.

 

I'm having a difficult time understanding what the 'filter_complex' and
'map' parameters are doing but I think I'm getting close. Can someone please
explain these and help me adjust my command above in order to achieve my
goal?

 

Thanks!