Limit mp4 atom size to something reasonable am: cb898dca47 am: 3a8c303038 am: 75e5b60ae9 am: 828c7c2c31 am: c80241d9c3 am: fbe7df6dd0 am: 2950996c2b am: 3fb31ed744  -s ours am: ded7c50d67 am: 01675cce76
am: 12afee52dc

Change-Id: Ic934c1003eeb50578a47b6aa5189f854f69bd25a