I recently started a project called jitsi-jingle primarily to add Jingle support to an audio-conferencing engine I was developing. It was also an opportunity to provide a replacement for the outdated smack jingle extension library (smackx-jingle) using the Jingle implementation of the active Jitsi project. This however turned out to be more challenging than it sounded as the OSGI dependecies in Jitsi and the internal abstraction model to support multiple protocols like SIP and XMPP made the code extraction difficult. There is a soon to be released libjitsi which should make the task easier, but I am running out of valuable time (I do this stuff in my spare time), so I had to choose another option for my immediate first release.
Enter mini-jingle from Thiago Rocha, the original developer of smackx-jingle (while he was at Jivesoftware) and the architect of Jingle Nodes. Project mini-jingle is a simple, but working Jingle implementation minus the media engine which makes it a very good fit with phono-java-audio. By adding support for basic raw RTP UDP packets, the standard PCMU (ulaw) voice codec and the Openfire jingle-nodes plugin, I now have a working Jingle library for Smack that should work most of the time either directly peer to peer or via a Jingle nodes media relay plugin for Openfire. There will always be the exception cases of where UDP packets are completely blocked by a firewall.
In order to test the library and put into practical use, I created a Spark plugin for it as a replacement for the old outdated Jingle plugin for simple voice calls between Spark users. When it is used with the Candy plugin for Openfire, it offers Spark users, group and private audio-conferencing from MUCs with Candy web clients as well. Just click on the telephone icon in the chat room toolbar.
If you intend to use it, pick it up from here and remember to delete the old jingle plugin in both the Spark folder and User data folders. Both won't work at the same time