XT910 Camera Problem

I have to fix the liinks because the forum does not allow me to use liinks, so I'll try to hide them from the filters using dot
Hi, first of all, this is my first thread, and I'm from Argentina so my english is very basic...
Here we go with the problem... I have a Xt910 with Android Jelly Bean (Official Brasil Retail), and i'm having some problems while recording videos.
There are 3 main problems, first is the quality recording 1080p videos... I don't know if this happens in all the xt910, but the video look so grainy, I don't know how to explain but I'll upload an example of me messin' around with my Numark Mixtrack Pro... It's just to show you what I'm talking about , the video I'll show you is 720p because 1080p videos are too large, but it's almost the same. I'd cut some seconds of video and uploaded the original to Tinyuppload
s000.tinyu.pload.com/index.php?file_id=02932312484516670403 (take off the dot on "tinyu.pload")
second problem is that while recording videos (most of my videos are DJ sets just for fun) the microphone stop working exacly at 10 minutes of recording, for 10 seconds and there start working again, I'll show you this putting a timecode over the parts on my set with 2 youtube videos, first stop working exacly at 10 min, and second stop at 20:10 min.
you.tube.com/watch?v=1gLTq2Qbcf4 (take off the dot on "yo.utu"and let "youtu")
yo.utu.be/GZ_hHFTapDo (same as first linnk)
3rd problem is that camera changes the contrast or bright (I can't tell you exacly which one changes) like after 21 minutes of video... I'll upload a little example here... this happens every time I record videos, I don't do anything, just the camera changes the contrast by itself
yo.utu.be/pVPPOICozCU (same here)
Oh, here's a cap with my phone kernel, android version, etc.
i.gya.zo.com/fba4d2ec1e95e424bb9f645e59a9496d.jpg (take off the dot on gya.zo and let "gyazo")
I'm using the default camera app to record videos.
Thanks for spending your time helping Me