Is my iPhone 5S draining battery too fast (and is it due to process mediaServerD?)

My iPhone 5s has always had less good battery life than my previous iPhone (4S), but I'd always assumed that it was due to the increased speed of the CPU/GPU and the increased screen size. It also sometimes seems warm in my pocket (not hot - but warmer than I would expect it to be in the ambient temperature.) This article: http://www.overthought.org/blog/2014/the-ultimate-guide-to-solving-ios-battery-drain Has been very popular in the last week, and I read it. Something I had never done before was to check the usage stats. See also the second from last paragraph here: https://www.apple.com/uk/batteries/iphone.html It appears that my phone never sleeps. The standby (usage+standby) figure is always the same as the usage figure. I assume that this is not normal. The other day it ran down from full charge to almost empty in 7 hours. As you can see from this screenshot: Is that normal battery life? Yesterday I ran Activity Monitor in Instruments on the phone when it was connected to my Mac - nothing seemed to be taking-up ridiculous CPU time, but I did notice that a process named **mediaserverd** was always at the top of the CPU chart - and always consuming 6% of CPU. I assume that it was designed to be permanently running, but I doubt that it's meant to be that power hungry. Please could someone else with a 5S run Activity Monitor in Instruments on their phone and let me know if the process is just as hungry on their phone. Thanks.