The latest version of this great software can be downloaded from Softpedia
Avidemux, a free video editor designed for simple cutting, filtering and encoding tasks that supports many file types including AVI, DVD, MP4, and ASF, is now at version 2.6.6.The Avidemux releases are few and far between, which is a real shame because this is a great piece of software, with multiple options. This latest iteration only incorporates a small number of fixes, but users should upgrade nonetheless.
According to the developers, the x264 preset has been upgraded to v2 in order to make sure that invalid Qp from older versions are not used any longer. Also, the PCM/LPCM management has been fixed and language support has been added for audio tracks.
A complete list of changes can be found in the official announcement. Keep in mind that the software is available on multiple platforms.
Download Avidemux 2.6.6 right now from Softpedia.