How to remove a section of audio from a YouTube video

[ARW]

I would like to publish a video of dashcam footage but want to remove comments made by my passenger halfway through the video

[The Natural Philosopher]

Well edit them out then.

Openshot is your friend

[SH]

or audacity.....

[Brian Gaff]

Can audacity load in the video then and just cut the audio? Brian

[The Natural Philosopher]

Dont think audacity does videos

[jkn]

I would probably try something like AVIdemux, you could extract the audio separately, work on that and then remux. I am sure there are better tailored apps out there, it partly depends on how much you want to learn to use them.

Editing it is probably a dodgy thing to do if this footage were to end up as some sort of legal proof, of course.

[SH]

you can actually open a MP4 file, and just export the audio out to a MP3.

Edit the audio and resave as a new MP3 audio file.

The next problem is then replacing the MP4's audio with the MP3 file.

[Paul]

Nobody would do it this way, but at least you don't need to learn a lot to do it (if a working recipe is available).

It can take several hours to craft one of these that actually works. But the point of this is that "ffmpeg can edit a video, even if the idea sucks".

# Suppress sound between 5..10 seconds and 15..20 seconds. Two sound notches.

ffmpeg -i in.mp4 -vcodec copy -af "volume=enable='between(t,5,10)':volume=0, volume=enable='between(t,15,20)':volume=0" out.mp4

Steps:

1) Input file is "in.mp4". 2) File is demuxed into a video stream and an audio stream. If you record off a TV set, there can be four or five streams, and you have to use a "number" to select the stream for each that you want. This requires usage of "map" or similar. 3) VCODEC copy specifies the video portion not be re-encoded, so there is no quality loss. 4) The command above does not specify an audio codec. This does not always end well. The person who crafted the above command, likely expects you already know this, and that extra cruft may be needed in the command. 5) Sometimes, the frame rate of the video is altered by commands like this. If you intended the frame rate to be 29.97, it sometimes pays to spell that out in the command. Occasionally you will notice the "audio pitch" in a video is off, and this can be because you did not explicitly tell FFMPEG what rates to use. Even though this should be patently obvious (that the existing settings be copied) from the users perspective.

This is how you determine the video and audio codec. GSpot is a tool for dissecting video and telling you what kind of streams are in there.

I prepared a sample video. I opened Audacity and used the Generate:Tone function to generate a 60 second 440Hz sine wave. I then pointed my video camera at the computer screen and shot a 60 second video while the sine wave played from the computer speakers. This gives an easily recognized stimulus to check for sound editing. Since I used a real camera to shoot video, the sound level is a function of what direction the camera microphone is pointing. The test movie is 250MB for 60 seconds worth.

GSpot 2.70a reports

test.MOV H.264 ("avc1") 23.976 FPS Length 57.932 seconds sowt: 16 bit signed little-endian 48000 Hz

The sowt codec is: "Apple QuickTime SWOT Little Endian PCM Audio (sowt) Codec"

After the FFMPEG run, the result is

out.MOV H.264 ("avc1") 23.976 FPS Length 57.932 seconds mp4a 48000 Hz 107kb/s stereo [2/0]

so it did indeed change/messwith the audio codec on its own.

We need some more recipes...

Pulling the edited audio (from out.MOV) into Audacity, it looks like this.

ffmpeg -i out.MOV -vn -acodec copy out.mp4 # The duff sound is mp4a and # is no good for my Audacity 2.1.0. # It's going to need conversion as it # is pulled out.

ffmpeg -i out.MOV -vn -ar 48000 -ac 2 -ab 192k -f mp3 out.mp3 # Convert HQ MP3

This is what the out.mp3 looks like in Audacity, to prove I've notched the sound precisely at the number of seconds indicated.

[Picture]

I don't enjoy editing video, but do you see how easy that is ? :-/

*******

What version of FFMPEG to use, depends on your OS. Version 3.33 for Win might be good for Windows XP. Version 4+ might work in Windows 7/8/10/11.

FFMPEG Windows executables come from "buildmeisters". Zeranoe used to make these, but has stopped. This is the latest buildmeister I've used. The buildmeister leaves this running at night, and it can do nightly. And the output may not be checked for functionality. You test the program when you get it, and see whether it works in Command Prompt or not.

Name: ffmpeg-2022-03-07-git-e645a1ddb9-full_build.7z Size: 44,315,699 bytes (42 MiB) SHA256: 4E3BDF5E4FB18A18F05805867B37D40CCCAD67F7CF8A7A8C2D4D3B24A5B74BC4 SHA1: 676A3D07F34580F444BF26E784089C3B05CC8810

Name: ffmpeg.exe Size: 121,132,032 bytes (115 MiB) SHA1: C1D14C672D9FAFC16BD633A14C56502792D24D13

The button on a github page can be pestilent. It might require a more recent browser to see what needs to be clicked and so on.

Paul

[Adrian Caspersz]

Playback the video on a TV, lowering the volume where required.

Record that holding a smartphone.

Passes for 'broadcast quality' these days....

[John J]

Comments by one of the apprentices?

[Dave Plowman (News]

Google video editing software? The one I've used is truly ancient and only runs on XP - but that can do a sound only edit.

There must be something around that is free these days. But may have quite a steep learning curve.