Raspberry Pi - OpenCV with Picam (4)

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4. OpenCV using raspivid


Now we'll use raspivid.

http://thinkrpi.wordpress.com/2013/05/22/opencvpi-cam-step-6-video/ 

I refer to this blog step6


4-1 Modify raspivid.c 

Modify raspivid.c or click to link for download.

camcv_vid0.c

------------------------------raspivid.c--------------------------------------------------------------------------

We  delete- all lines related to the preview component,
- all lines related to the encoder component.
- all lines related to inline command parsing and picture info…

We change :
- add the callback directly to the video_port  (line 286)
- create and attach the pool (to get/send message)  to the video port… (line 320)
- change format encoding to ENCODING_I420 in line (268) (instead of OPAQUE)

---------------------------------------------------------------------------------------------------------------------

change name to camcv.c

mv camcv_vid0.c camcv.c

make

./camcv

If you meet this error
---------------------------------------------------------------------------------------------

mmal: main: Failed to create camera component
mmal: Failed to run camera app. Please check for firmware updates
---------------------------------------------------------------------------------------------

change Line 489

nano camcv.c
--------------------------------------------------------------------------------------------------------------------------
else if (!raspipreview_create(&state.preview_parameters))
=> 
else if ( (status = raspipreview_create(&state.preview_parameters)) != MMAL_SUCCESS)
--------------------------------------------------------------------------------------------------------------------------

Re cmake

very slowly but recoding vidio

If you change resolution

Modify Line 183

and 

color<--> gray change

Line 124

Reference my case.

• 320×240 color : FPS = 27,2
• 320×240 gray : FPS = 28,6
• 640×480 color : FPS = 8
• 640×480 gray : FPS = 17