In the good old days of Jaunty, Ubuntu had an asound.conf file that could be patched to increase the range of audio volume. This is no longer supported in Karmic. Instead, the PulseAudio volume control allows up to a 50% increase over the norm. Unfortunately, depending on how the .avi file was created, this may not be enough. One solution (there may be others) is to transcode the file into another, boosting the audio volume in the process. This article will provide instructions on how to do it with the transcode utility. It may also be possible to do it with mencoder or avidemux. I am uncertain of the syntax for those and if one of my readers does, please comment on it.
Transcode is available in the standard repositories. Install it from the command line (sudo apt-get install transcode) or use Synaptic. Here is the syntax of the command:
transcode -i input.avi – P 1 -s <desired gain> -N 0x55 -o output.avi
Let’s clarify this a little. Input.avi and output.avi are the names of your input and output files. If your input name contains spaces you should rename it to something without spaces. Otherwise you will have to use the “escape” character “\” for the command to parse correctly. For example “My Rip.avi” would be entered as “My\ Rip.avi”. This gets messy, so just rename the file.
0x55 is telling transcode that you want the output sound to be mp3 encoded. You can have other encodings if you so desire. Read the manual by entering man transcode on a command line for further information.
<desired gain> requires a little knowledge about decibels. Decibels follow a logarithmic scale. To double your volume you would enter a value of 3. A value of 6 would quadruple the volume. A value of 2 would result in an increase of about 60% Stay with low values, A value to high could damage your speakers, and sound distortion is likely. Replace <desired gain> with a value of your choosing.
That’s it for now. Let’s hope Ubuntu finally gets sound right in Lucid.