Not sure which platform Linux/WinCE and BSP(i.MX27?) you are using.
Normally it should return like that.
Please check:
1. At initInfo, is the video bitstream header correctly parsed by VPU?
2. Which mode file or stream mode are using by you? For file mode, it should always input
one frame data, in stream mode, it should input at least one frame date.
3. You can try with unit-test code released with ltib package first if using Linux BSP.
Hope will do some help to you
B.R
Jetic