To use Elgato Game Capture HD to capture Xbox One chat between friends, or party chat, you'll need to take a few additional steps.
Solution:
1) In the Xbox One interface, go to Settings, then Kinect.
2) In the Kinect settings, make sure "Use Kinect microphone for chat" is checked.
NOTE: You may need to calibrate and set up your Kinect before the microphone is available.
3) Now go into your party, and turn on voice chat.
WARNING: Be sure to unplug the chat headset, and be sure to keep it unplugged.
Now your party chat audio and all other voice audio will go through the HDMI cable to your Elgato Game Capture HD, so it can be captured.
Solution:
1) In the Xbox One interface, go to Settings, then Kinect.
2) In the Kinect settings, make sure "Use Kinect microphone for chat" is checked.
NOTE: You may need to calibrate and set up your Kinect before the microphone is available.
3) Now go into your party, and turn on voice chat.
WARNING: Be sure to unplug the chat headset, and be sure to keep it unplugged.
Now your party chat audio and all other voice audio will go through the HDMI cable to your Elgato Game Capture HD, so it can be captured.