This article shows you how to convert the audio sampling rate. You might need this information if you are trying to append avi segments but are unable to because the audio sampling rates are different.
Open up virtualdub and load your video. Go to the audio menu and activate full processing mode. Make sure the audio compression is set to uncompressed. Select advanced filtering and go to the filters.
Once there recreate the following with a sample rate of your choice*:
* The configure button lets you do this.
Never use “New Rate”, this will only ‘stretch’ the audio across the video creating a synch problem. See the article about fixing audio-video synch problems.
Set full processing mode for video and configure the desired codec OR leave it on direct stream copy.
Note: it may be necessary to convert the sample rate of multiple files if your objective is to append video.