Offloading a video portion of a video call

1. A method for offloading a video portion of a video call session from a cellular network to a wireless local area network (WLAN), the method comprising a wireless communication device:

participating in a video call with a remote device over a connection between the wireless communication device and a cellular network implementing a Long Term Evolution (LTE) technology, wherein the video call comprises a first video stream carried over a first bearer on the cellular network and an audio stream carried over a second bearer on the cellular network, and wherein the second bearer is a voice over LTE (VoLTE) bearer;

establishing a connection between the wireless communication device and a WLAN;

performing a call setup procedure with the remote device to establish a second video stream, the second video stream being carried over the WLAN;

terminating the first video stream after establishing the second video stream; and

using the second video stream and the audio stream to continue the video call.

2. The method of claim 1 , further comprising the wireless communication device:

displaying the first video stream while performing the call setup procedure; and

switching from displaying the first video stream to displaying the second video stream prior to terminating the first video stream.

3. The method of claim 1 , further comprising the wireless communication device:

measuring a quality of the WLAN prior to establishing the second video stream; and

performing the call setup procedure with the remote device and terminating the first video stream only in an instance in which the quality of the WLAN satisfies a threshold connection quality.

4. The method of claim 1 , further comprising the wireless communication device performing registration to a video call service over the WLAN prior to performing the call setup procedure.

5. The method of claim 1 , wherein terminating the first video stream comprises sending a termination message to the remote device.

6. The method of claim 5 , wherein the termination message comprises one of a session initiation protocol (SIP) BYE message or a SIP re-invite message.

7. The method of claim 1 , further comprising the wireless communication device using real-time control protocol (RTCP) to enable synchronization of the second video stream and the audio stream.

8. A wireless communication device comprising:

a cellular interface configured to transmit data to and receive data from a cellular network;

a wireless local area network (WLAN) interface configured to transmit data to and receive data from a WLAN; and

processing circuitry coupled with the cellular interface and with the WLAN interface, the processing circuitry configured to control the wireless communication device to at least:

participate in a video call with a remote device over a connection between the wireless communication device and the cellular network, the video call comprising a first video stream carried over a first bearer on the cellular network and a packet switched audio stream carried over a second bearer on the cellular network;

establish a connection between the wireless communication device and the WLAN;

perform a call setup procedure with the remote device to establish a second video stream, the second video stream being carried over the WLAN;

terminate the first video stream after establishing the second video stream; and

use the second video stream and the audio stream to continue the video call.

9. The wireless communication device of claim 8 , wherein the cellular network comprises a network implementing a Long Term Evolution (LTE) technology, and wherein the packet switched audio stream is carried over a voice over LTE (VoLTE) bearer.

10. The wireless communication device of claim 8 , wherein the processing circuitry is further configured to control the wireless communication device to:

display the first video stream while performing the call setup procedure; and

switch from displaying the first video stream to displaying the second video stream prior to terminating the first video stream.

11. The wireless communication device of claim 8 , wherein the processing circuitry is further configured to control the wireless communication device to:

measure a quality of the WLAN prior to establishing the second video stream; and

perform the call setup procedure with the remote device and terminate the first video stream only in an instance in which the quality of the WLAN satisfies a threshold connection quality.

12. The wireless communication device of claim 8 , wherein the processing circuitry is further configured to control the wireless communication device to perform registration to a video call service over the WLAN prior to performing the call setup procedure.

13. The wireless communication device of claim 8 , wherein the processing circuitry is further configured to control the wireless communication device to terminate the first video stream at least in part by controlling the wireless communication device to send a termination message to the remote device.

14. The wireless communication device of claim 8 , wherein the processing circuitry is further configured to control the wireless communication device to use real-time control protocol (RTCP) to enable synchronization of the second video stream and the audio stream.

15. A non-transitory computer readable storage medium having computer program code stored thereon, the computer program code comprising program code, which, when executed by one or more processors implemented on a wireless communication device, is configured to cause the wireless communication device to perform a method comprising:

participating in a video call with a remote device over a connection between the wireless communication device and a cellular network, the video call comprising a first video stream carried over a first bearer on the cellular network and an audio stream carried over a second bearer on the cellular network;

establishing a connection between the wireless communication device and a wireless local area network (WLAN);

performing a call setup procedure with the remote device to establish a second video stream, the second video stream being carried over the WLAN;

terminating the first video stream after establishing the second video stream; and

using the second video stream and the audio stream to continue the video call.

16. The non-transitory computer readable storage medium of claim 15 , wherein the audio stream is a packet switched audio stream.

17. The non-transitory computer readable storage medium of claim 15 , wherein the cellular network comprises a network implementing a Long Term Evolution (LTE) technology, and wherein the audio stream is carried over a voice over LTE (VoLTE) bearer.

18. The non-transitory computer readable storage medium of claim 15 , wherein the method further comprises:

displaying the first video stream while performing the call setup procedure; and

switching from displaying the first video stream to displaying the second video stream prior to terminating the first video stream.

19. The non-transitory computer readable storage medium of claim 15 , wherein the method further comprises:

measuring a quality of the WLAN prior to establishing the second video stream; and

performing the call setup procedure with the remote device and terminating the first video stream only in an instance in which the quality of the WLAN satisfies a threshold connection quality.

20. The non-transitory computer readable storage medium of claim 15 , wherein the method further comprises performing registration to a video call service over the WLAN prior to performing the call setup procedure.