Hello I'm migrating an office setup from asterisk to FS and in the process I was considering using G726-32 for some bandwidth starved remote endpoints. However I only get metallic/garbled audio with that codec even when simply playing moh to the endpoint, while other codecs work fine (G711U/A, G722, GSM). G732-16 is inaudible, G732-40 sounds marginally better but still garbled and really worse than G711. The setup is FS 1.2.12 from FS' yum repo on a centos6 64bit KVM guest (centos6 64bit host). But please don't shoot ! :) - I know about virtual environment limitations but for these tests the host is only lightly loaded, there aren't any calls to the FS instance except my tests, and the fact that it works with other codecs makes me think that virtualization is not the issue here. I may be wrong though. Is there any guide for debugging that kind of problem before reverting to a fresh install on bare-metal with the latest HEAD ? Until now I've tried: - improving timers ; but the default soft timer (which I guess uses timerd) works best. The time interval between sent packets on a tcpdump trace looks identical to the output of "timer_test", so that doesn't seem to be a network/jitter problem. And there's no problem with other codecs, but maybe G726-XX is specific. For info the guest's clocksource is kvm_clock, while the host uses tsc. - using different endpoints: the production ones are Linksys PAP2 ("fixed" for 20ms psize, and G726-32 SDP type indentification), but the same thing happens with linphone on a fedora 19 laptop. A call with rtp media going through FS without transcoding - G726-32 to G726-32 - works perfectly (I can't hear the difference with G711). The problem is only when there's transcoding to G726 (from wav for moh, or from any other codec when bridging). I've looked at the wiki, posts, changelogs, jira, ..., but am a bit at a loss now. Any pointers ? Except that little problem, FS rocks, and I'm happy I can finally ditch asterisk. Kudos to the core devs and contributors. Ivan