Camera2 Allocation of type YUV_420_888 getTimestamp() always zero

[Matt Fischler]

When I create an allocation with ImageFormat YUV_420_888 and use Allocation.setOnBufferAvailableListener(..) I get the callback to fire and I receive an allocation and I can update it with allocation.ioReceive(). Before the allocation.ioReceive() call, allocation.getTimeStamp = -1 as expeced. But after the ioReceive call, the timesamp is always zero. The allocation is otherwise fine and I can do all my image processing. If I use ImageReader with setOnImageAvailableListener instead, image.getTimeStamp() always works fine, but not with the allocation onBufferAvailable.

Thanks,

Matt