You have to turn on the archives so your streams can be saved. Once you have made an account go to your settings and then go to channels and videos and make sure the box is checked for archive videos.
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Once that is done all your streams will be saved for a little while. You can access them in your video manager. A little prompt comes up even telling you that they will not be saved.
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What you do is click on the video you want to be saved and copy the URL.
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You then paste the URL and hit download, then download the videos and they are then saved.
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As of right now there is no way to hear everyone in your party, guess they are adding that feature. But, if we are all streaming we just put [ Register or Signin to view external links. ] and then add our channel names at the end, so it will look like this [ Register or Signin to view external links. ] and it will have all of our steams on one window. Not sure how many can be added on. The most I have done it with is 4. So, if we have more people we will just have to have multiple multitwitches going.

Also, if you are unaware, you can easily save awesome moments as well with the Xbox Record option, or just have all your games being saved to the DVR. You upload them to Upload Studio and there you can upload them to Skydrive (One Drive) and then download them to your PC as well, allowing you to upload them to Youtube. It's really easy, you just right click the video and download it, or click the video, do some editing and then download.
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