This involves transcoding the streams, which requires a good amount of processing power (i.e. a small CPU won't handle it if the original stream is HD, for example). TVheadend in itself doesn't do transcoding even though there's a fork (https://github.com/john-tornblom/tvheadend) that is still being tested.
What I would do is use VLC to transcode the stream.
But the streams are 3-5 mbps (for SD) at most. I don't know why this would overload your Android phone?
Hope this helps.