Ever downloaded a video from the internet that is barely audible? Fixing the audio volume is a simple matter of demuxing the video file into its constituting video and audio channels, adding a constant gain to the audio channel and then packing both together into a video container. This tutorial will show you how to do that.
Years ago, I wrote a similar tutorial showing readers how to increase the volume of the audio channel of a video file using a software called VirtualDub. The method described worked only with AVI files. The new method that I’m going to describe in this tutorial works with common video formats such as MP4, MKV and AVI.
We will use a software called Avidemux. It’s a portable software, so after downloading simply extract the contents of the archive into a folder and launch the file called avidemux.exe.
From the File menu, click Open and select the video file whose volume you want to increase.
On the left hand side, under Video Output choose the Copy option. This should already be selected by default. Under Audio Output, choose AAC (lav). Then click on the button “Filters” under Audio Output.
In the Audio Filters window, click on the button that says “None” next to Gain and from the drop-down menu choose “Manual (dB)”.
In the Gain value enter the figure in decibel corresponding to the amplification desired by referring to the Decibel-Ratio chart given below. For example, a dB value of 2 will increase the volume by a ratio of 1.58 (or 58%). A dB value of 3 will double the audio volume. A dB value of 6 will quadruple (x4) the audio volume and so on.
| Decibel (dB) | Amplification (Ratio) |
| +30 dB | 1000 |
| +20 dB | 100 |
| 16 dB | 40 |
| 13 dB | 20 |
| 10 dB | 10 |
| 9 dB | 8 |
| 8 dB | 6.31 |
| 7 dB | 5.01 |
| 6 dB | 4 |
| 5 dB | 3.16 |
| 4 dB | 2.51 |
| 3 dB | 2 |
| 2 dB | 1.58 |
| 1 dB | 1.26 |
Make sure you don’t increase the volume too much, otherwise there will be clipping of the audio signal and this will sound on your speakers as static, which is certainly undesirable.
You can preview the results by switching to “Output” by clicking on the button shown below and then playing the video file using the playback controls on the bottom of the program’s window.
Under Output format, choose either MKV muxer or AVI muxer or MP4 muxer depending on whether the original file was MKV or AVI or MP4. But you can choose any video container, it doesn’t really matter.
Save the video by clicking on the Save button. The program will start encoding which will take just a couple of minutes at most.
Awesome tutorial.
Help please… Every time I try to save the video it says CRASH and the program closes and the video is no where to be found. I followed each instruction to the letter and have tried every dB value from 0 to 30 with the same results. I don't know anything else to try and I can't find out what is going through the internet. So if you know what I'm doing wrong or have any ideas please help. It would be greatly appreciated.
I can't say why you are experiencing crashes. I suggest you select another audio codec, other than AAC (lav) and see what happens. Also verify whether the program crashes for every video file or that particular one.
Thank you for your help… I switched to AC3 (lav) and it worked perfectly!
I’m afraid that you need to reinstall the software then try again. Actually, you can increase volume by using Windows Movie Maker directly. It’s a preinstalled application for Windows operating system. Also, the operations are quite easy. You can simply go to “Edit” tab then adjust volume in the option of “Video Volume” when editing the video file. Aside from this program, video converter studio（http://www.apowersoft.com/video-converter-studio.html）is also capable increasing volume. And it offers more advanced editing functions.
..concerning the the Windows Movie maker can you add all movies files to this program? i tried to add a movie to it but nothing happen./Lenny
Yes, my experience exactly the same. As soon as the 'Save' tab is pressed the Avidemux program crashes. Unfortunately there is simply too much of this half baked rubbish on the internet now. Over the past few years it has become harder and harder to find reliable information for what should be simply questions. It has got to the point where forum sites are no longer viable for resource material
Followed the instructions point for point. It did not change the volume in the preview, or in the finished product. Either a step is missing in this tutorial, or it just doesn't work.
Worked fine for me. With that said, I couldn't hear my audio adjustments by using the preview function. However, when I saved the file and played it back the increase in audio was certainly there.
Thanks, Kaushik!
No good for me. When I follow the instructions and click save, I get: "Cannot setup audio encoder, make sure your stream is compatible with audio encoder (number of channels, bitrate, format)" – followed by: "File … was NOT saved correctly" (where "…" is the output pathfilename). Also the downloaded file is *not* a simple archive file, it's a fully-fledged installer.
hello I had the same problem what was the solution?/Lenny
… and if I choose other audio codecs it just segfaults (like others have said). I'm on 32-bit Windows 7. Not to be rude, but, this program is clearly a bit of a steaming pile!
I also could not hear a change in volume when I previewed my video, but the change was apparent after I saved the video.
I can't hear any audio from the video file before and after editing, but I hear it using other players.
I´m happy. It works perfectly!!!! thanks
I downloaded avidemux & followed all steps but could not preview the result by switching to "output" after clicking on the button shown. Plz mention all the steps one by one.
by manual gain sound is not increasing . And also there is no AAC(lav) there is AAC(Faac) and others.
Works like a charm, thanks!
Mike Davies in England.
To everyone who's volume didn't change in the finished file… use "gspot" to find what the audio codec is being used in the file, then match that with the 'audio output' in this pgm. for me the movie used 'ac3', and using 'aac-lav' wasn't working until I changed it to 'ac3-lav'. hope this helps