Observer XT freezes or blocks in Data Profile when video uses AC3 audio codec
Last updated: Nov 01, 2026
Problem
Observer XT becomes unresponsive or blocks when the user opens a Data Profile or attempts to run a Behavioral Analysis, specifically when the linked video files were encoded with an AC3 audio codec.
Details
The issue occurs because recent versions of Windows no longer include a built-in AC3 audio filter. Observer XT attempts to access the audio codec during playback or data profile operations and blocks when the filter is not found. Affects projects where video files were recorded or converted using AC3 audio encoding.
Solution
1. Install LAV Filters, a free open-source DirectShow filter pack that includes AC3 audio decoding support. LAV Filters can be downloaded from the official GitHub releases page.
2. After installing LAV Filters, restart Observer XT and attempt to open the Data Profile and run Behavioral Analysis again.
3. If the issue persists, verify that the LAV Audio Decoder is enabled and set as the preferred filter for AC3 content in the LAV Audio configuration panel.