Call-related features
Can they make video calls?
Except the Yate client, which can only make audio calls, all the other apps in the Roundup can make both audio as well as video calls.
All the apps support a variety of VoIP codecs. Jitsi, Ekiga and Skype also let you enable or disable particular codecs and even prioritise them. All support the popular Speex audio codec, which minimises bandwidth usage by using variable bitrate. They all also support the iLBC codec, which is robust to packet loss. Additionally, Jitsi and Ekiga support Skype’s SILK audio codec.
To improve the quality of audio, some clients, such as Empathy, Ekiga and Jitsi also have controls to enable features such as echo cancellation and noise cancellation.
Skype uses H.265 for high-definition video and the VP8 codec for standard definition video, which is also available on Jitsi– which also uses the H.264 as well as H.263 codecs, just like Ekiga.
Every client handled one-on-one audio and video calls with relative ease with hardly any noticeable audio lag or video distortions. We also used the clients while the network was busy downloading a torrent. Even in such a situation, no client faced any issues making audio calls. Video was, however, a different matter. Only Skype and Jitsi were able to establish connections with decent-quality video.
Further, Ekiga and Jitsi also let you configure the resolution of the video. While Ekiga supports resolution from 176x144 to 704x576, Jitsi can go from 160x100 to 1,280x720 and even lets you set a custom frame rate and a bitrate for the video.
Some clients also don’t offer all the features on all the protocols they support. Jitsi, for example, offers audio and video calls only over SIP and XMPP. Another thing we noticed about Jitsi is that while it can work with any XMPP and SIP service, connections established with its Jit.si XMPP service were more stable than other services.
Jitsi also has built-in call recording. You can record audio made over SIP, XMPP or even Google Talk accounts. Empathy and Ekiga don’t have controls to record calls but you can use an external app, such as Audacity to record the calls. Skype has third-party tools, such as the Skype-Call-Recorder.