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iMX6 camera preview IPU functionality

Question asked by Alex Dmitriev on Dec 11, 2014
Latest reply on Dec 11, 2014 by Alex Dmitriev

Hello,

there is a "camera preview" function in iMX's image processing unit.

 

User guide explanation is very short:

37.1.2.1.6.3 Camera Preview

• Tearing artifacts can be prevented by (automatic) page-flip double buffering in

system memory

• Alternatively, the video stream from an image sensor can be sent directly to the

display buffer used for screen refresh. The significance of this option is that only a

single frame buffer is needed (and not two). This buffer may be located either in

system memory or in an external display controller.

• This option is useful, e.g., in a low frame rate, when tearing is not visible.

• When tearing must be prevented, the refresh cycle in the display can be

synchronized with the timing signals from the sensor (two refresh cycles for each

input frame): the IPU receives a VSYNC signal from the sensor and generates

from it synchronization signals for the display.

 

 

The question is: how to configure IPU to stream video directly from sensor to screen without CPU interaction?

 

Main idea to implement "instant start" appearence, show video from bootloader and then start linux.

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