I’ve recently been playing around with various mobile SIP clients, testing how well they work making calls to Ekiga 3.2.7 clients running on the desktop. Following are some notes I’ve collected using Sipdroid 2.0.1 Beta, running on a Motorola Milestone with Android 2.1.
In all tests, I am using the Milestone on the Vodafone New Zealand 3G network, while my desktop clients are all connected to either corporate LANs with public IP addresses, or running NATed on home networks.
Generally, for voice calls, Sipdroid plays quite well with Ekiga using this network arrangement, but there are some niggles regarding the various audio codecs either SIP application supports. A summary of this follows.
First, it appears that the speex (11kbit) codec in Sipdroid’s implementation is just plain incompatible with either the Speex 8khz or Speex 16khz codecs featured in Ekiga.
Enabling only the speex (11kbit) codec in Sipdroid, and Speex 8Khz in Ekiga, I could make calls to Ekiga from the Milestone fine, but calling from Ekiga to the Milestone results in an incompatible codec error at the phone end, and the call then immediately terminates.
Enabling only speex (11kbit) in Sipdroid, and Speex 16Khz in Ekiga, calls cannot be made in either direction. Calling from the Milestone to the PC, Ekiga gets an incoming call notification but on accepting the call, the connection is lost at the PC end, with a notification that the call was missed. On the Milestone, it simply continuously reads “Dialling”. Connecting to the Milestone from the PC, one gets the same codec error as above before the call terminates.
Calls made from the Milestone to Ekiga worked great, and vice versa.
Calls made from the Milestone to Ekiga using PCMU also worked great, and vice versa.
An interesting observation at this point is that if the PCMA, PCMU and Speex codecs are all enabled in both Ekiga and Sipdroid, and in Ekiga Speex is sorted in the audio codecs window to be at the top, then calls made from Ekiga to the Milestone will fail with the codec incompatibility error. Calls made from the Milestone to Ekiga however are fine, but will fall back to a PCMU/PCMA codec.
Calls made from the Milestone to Ekiga using the G722 audio codec also worked great, and vice versa.
Calls made from the Milestone to Ekiga using the GSM audio codec also worked great, and vice versa.