Crank up volume on parts of the audio track in a video: I have an MP4 of an interview and one of the two people talking was not caught well in the audio track and is far too soft spoken. My challenge now: increase the volume of only that speaker.
- save audio from MP4 in a separate MP3 file (using VLC)
- identify the soft parts and amplify the sound in those sections (using Audacity)
- add the edited MP3 audio track to the MP4 – replacing the original video track (using FFmpeg or with Clideo.com)
Open VLC (open source software). Click on Media | Convert / Save
Add the mp4 file. Click on Convert/Save.
Select the Profile Audio – MP3. Define the name of the output file – using the extension .mp3.
Click on Start to commence processing. In a few seconds, the MP3 file is created with the audiotrack from the video.
Load this MP3 in Audacity – another open source tool:
Select the low volume parts and use Effects | Amplify to increase the sound level for each of these parts (one by one)
The result will be a cranked up wave – indicating more volume.
Export the thus improved audio file
The next challenge: combine this MP3 with MP4 – replacing the audio track in the MP4 file.
Several tools are available for this:
- Clideo.com – free website, adding its own watermark and perform quite well
- ClipChamp – Windows utility, also delivering good results in a simple manner
- FFmpeg – open source command line utility for manipulating video and audio files; I did not get the perfect result thusfar; getting the command line exactly right seems a little bit tricky
The command used on the command line with FFmpeg to combine video and audio:
ffmpeg –i “C:\Users\lucas_j\Downloads\prijstrekkingAdventOfCode – Copy.mp4” -i “C:\Users\lucas_j\Downloads\AudioprijstrekkingAdventOfCodeAmplified.mp3” -c:v copy -c:a aac -strict experimental “C:\Users\lucas_j\Downloads\prijstrekkingAdventOfCodeWithAmplifiedAudio.mp4”
It seems like the video’s own audio is not reduced (enough). I probably have to explicitly suppress the video’s audio track.
Create a project, import the MP4 and MP3 files. Add both files to the project – both starting at t=0. Mute the audio in the MP4 file, as shown in this screenshot (right mouse click on video, pick Audio | Mute).,
This completes the work in ClipChamp. Export the project – as shown.
This results in an MP4 file with much improved audio levels.
Article on Clideo.com How to Replace Audio in Video – https://clideo.com/resources/how-to-replace-audio-in-video
VLC at VideoLAN – https://www.videolan.org/vlc/
Audacity – https://www.audacityteam.org/ – open source tool for audio editing
FFmpeg – homepage- https://ffmpeg.org/ – complete, open source cross-platform solution to record, convert and stream audio and video.
FFmpeg downloads for Windows – https://www.gyan.dev/ffmpeg/builds/
How to Merge Audio and Video Using FFmpeg – https://filmora.wondershare.com/video-editor/ffmpeg-merge-audio-and-video.html