While recording from file microphone records noise

[morphingstar]

No success in trying to switch microphone OFF or find instruction how to do this and where the switch is in A. manual.
I am running an MP4 file and record the audio.
If the phone rings or somebody talks nearby the microphone records this on top of the audio which is playing on computer's audio player.
I found this MP4 to MP3 method easier than extracting the audio with respective software, as I can edit the 2 ends and more.
It surprises me that switching off the microphone seems impossible or a deep secret with a software of decades of development.
Can't remember if FreeEdit could do it.
Please add to the manual after responding here, thanks.

WIN10 64 updated, A 2.1.0.

[kozikowski]

It's not Audacity's problem. Computers naturally want to play sound files, movies or internet shows to the speakers [pause] and record the internal microphone or other USB sound device. There is no recording the internet or playback of a file. That requires a connection between Playback and Record services and those are not natural. If you have one of those connections then you had to put it there with special software or drivers. That's a good place to look for solutions.

One of the problems of crossing the streams (apologies to Ghostbusters) is you can't steer it. There is no recording just one thing. The software usually gives you "Everything on the Computer." That's why your built-in microphone showed up in your recording.

Can't remember if FreeEdit could do it.

That may be a good alternative.

I got nothing. That cross is even harder to do well on Macs.

Koz

[kozikowski]

How is that easier than just opening up the file in Audacity and lopping off the trash at each end? If you install the FFMpeg software, Audacity will open up many different audio and video files.

MP4 to MP3

Picking up compression distortion at each step. Any thought to minimizing that?

Koz

[DVDdoug]

Like Koz says, if you install the optional FFmpeg Import/Export Library] you can open the MP4 in audacity and you won't have to "record" it. You'll generally get better quality and it's easier and faster... If you already have a digital audio file, It's silly to re-record except as a last resort when you have a weird format that you can't decode.

If the phone rings or somebody talks nearby the microphone records this on top of the audio

Even in a "quiet room" the background noise exceeds the background noise on a professional-digital recording, and the microphone preamp will add "electronic noise".

No success in trying to switch microphone OFF or find instruction how to do this

Right-click the Windows speaker/volume icon. Select Open Sound Settings, and you should be able to navigate to the microphone and disable it. Starting from that same screen there are also Microphone Privacy Settings that should allow you to turn it off.

Or after clicking the speaker/volume icon, open the Volume Mixer and you should be able to mute or turn-down the microphone.

[kozikowski]

you should be able to navigate to the microphone and disable it.

Unless another application really, really wants to use it such as Skype, who likes to take over control of your sound services without telling you. Worse if you leave Skype or other chat or conference program running in the background.

Koz