Is it possible to "bleep out" small segments of audio from an .mkv file?

[end-user]

I recorded a video capture using OBS studio. Unfortunately my computer mic was on and my voice is mixed in with the audio from the video. I would like to blot out my voice from the .mkv file with silence. I don't care if the audio from the video itself gets blotted out along with my voice for these small segments. Does anyone know how to do this using avidemux or any other kind of editor?

My OS is Windows 10. Here's the file info from MediaInfo:


Format : Matroska
Format version : Version 4
File size : 676 MiB
Duration : 19 min 49 s
Overall bit rate mode : Variable
Overall bit rate : 4 763 kb/s
Writing application : Lavf58.20.100
Writing library : Lavf58.20.100
ErrorDetectionType : Per level 1

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings : CABAC / 2 Ref Frames
Format settings, CABAC : Yes
Format settings, RefFrames : 2 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 19 min 49 s
Bit rate mode : Variable
Maximum bit rate : 40.0 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 60.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Default : Yes
Forced : No
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.470 System B/G

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : A_AAC-2
Duration : 19 min 49 s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Delay relative to video : 3 ms
Default : Yes
Forced : No

[davexnet]

Basic audio editing?

Use an audio editor - for example
Audacity

Load the audio file, zoom in (CTRL 1), mark the spot with the mouse,
effects/amplify - set the amplification to about -50.
Repeat as necessary

File/export/save as Wav

Load the original video in Avidemux, disable the original audio, load the new wave file
Audio(on the left) / change from "copy" to aac/fdk

Save the new file

[end-user]

Thanks! I've been able to do everything right up to the point where you say to load the new wave file. I can't figure out how to do that. In avidemux the audio tab at the top only gives me the option "Select Track" and the Audio Output on the left only has the different output formats. Could you or someone explain in a bit more detail how to load the new wave file?

Oh, and here's a thread I found from 2012 (but interestingly last posted to only 2 days ago) that touches on a similar issue in case anyone reading this in the future wants to reference it.

https://forum.videohelp.com/threads/344608-Insert-beep-audio-to-black-out-words-in-a-mp4-file

[davexnet]

It's here:

[end-user]

Hey, it worked! Thanks a bunch! I was a little worried initially, because when I added the newly edited audio track and played it within avidemux before saving it, all I heard was loud static. Then after I saved it and played it in VLC, it sounded great - no A-V sync issues or anything. So thanks again!

[Cornucopia]

Using fade outs & ins is workable, but it can sometime result in noticeable "pumping" much like a (manual) noise gate. It has "air"/ambience, then it doesn't, then it does again.

Possibly better is to do what the pros do and drop in "room tone" aka silent ambience, in those gaps, doing micro-crossfades at the transitions. Often COMPLETELY hides the offending segments without notice.
If you do this, I recommend you record along segment of room tone* with which to work, so you don't fall into the trap of needing to loop a short segment. That DOES become noticeable.

Have done thousands of hours of that stuff, so I know it can work if properly acquired & matched.

Scott

*Get a recording for each room used, with exact same setup and levels as main recording, in order to best match.

[end-user]

Thanks for the additional advice Scott. Makes sense. Much appreciated.

[netmask56]

As it's a MKV file you could just remux the fixed audio track back into the mkv file using MKVToolNix, no need for avidemux.