AnsweredAssumed Answered

i.MX8M can't show analog camera frame correctly

Question asked by Benson Huang on Apr 30, 2018
Latest reply on May 3, 2018 by Wigros Sun

Hi,

 

Our platform: i.MX8M

Video decoder: ISL79987

Analog camera: 2 camera 2 lane

Field: V4L2_FIELD_INTERLACED (NTSC)

Command: yavta -fUYVY -s720x480 -t1/30 --field seq-tb -n4 -c -F /dev/video0

 

      RAW Pixels  (1440x480) (left top is first camera top part, right top is second camera bottom part, left down is first camera bottom part, right down is second camera top part)

 

      RAW Pixels  (720x480) (left top and right top mix together, left down and right down mix together)

We have the following questions.

1. We capture 720x480 frame but it seems each captured frame is 720x240. Odd field and even field are all 720x120.

    Why can't we get 720x240 odd and even field?

2. The captured frame order is camera 1 -> camera 2 -> camera 1 -> camera 2.

    Could we get channel 1 (camera 1) total frame and then get channel 2 (camera 2) total frame?

    How could we ensure the order is correct?

3. What is the black bar between the frames? Could we have some way to remove it?

4. Our video source is NTSC. Bottom part is transmitted first and then top part.

    In yavta, do we need to use interlaced-bt for field setting?

5. If the deinterlace function works, what is the expected frame behavior?

    For 720x480 frame, the top part is channel 1 (camera 1) preview and the bottom part is channel 2 (camera 2) preview?

6. Are there any other tools for verifying the captured frame except yavta?

 

Thanks.

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