MPEG4Source: fix fragmented read. am: 6b401a3376 am: 96114e7c5d am: bbc5c8fc60 am: 067ab2f74e am: 218692ec4f am: fa7be9da95 am: b31373e62c am: 2df7cd6571 am: 64e7c6089f am: 739585fb8d am: a3df50b011
am: 189c8ca25f

Change-Id: I90d4a5f82a27f1ad19af965b04576b3837910b58