Might be a false positive on AC3 filter... regardless though, if you have something like the K-lite codec pack you can use the codec tweak tool to boost the gain or volume on AC3 streams. Using the codec tweak tool you chould be able to click on 'directshow filters' in the configuration section and then choose an audio decoder from the list and play with the settings. If you manage to get AC3filter working it's the easiest to deal with and you can adjust it's settings independantly of your other audio decoders. You can boost the gain on the AC3 streams and that will raise the volume of your DVD videos compared to the rest of your audio so you aren't blasting your eardrums during the inflight music.. I currently have the gain on my AC3filter install set to +12dB