How Remove Camera Preview to Raspberry Pi

How remove camera preview to raspberry pi

Try the nopreview option

pkill uv4l
uv4l --driver raspicam --auto-video_nr --encoding yuv420 --width 320 --height 240 --nopreview
export LD_PRELOAD=/usr/lib/uv4l/uv4lext/armv6l/libuv4lext.so

Hope that helps

Display camera preview on Raspberry Pi Android things

As commented in another issue the RPI3 camera HAL only support one target surface at a time, this apparently come from a limitation of the underlying V4L2 implementation.

The following workaround should be possible:

  • for preview: use a SurfaceView as the target surface
  • when taking picture: in the CaptureCallback use PixelCopy to grab the raw frame from the surface

You can find a tentative example based on the android-Camera2Basic kotlin sample: here

Raspberry Pi - How to do other things while preview is running?

It is likely not the preview that is blocking your program, but using sleep(20).

Whilst the 'sleep' is occurring, nothing else can process. This causes the block you are noticing. You could fix this by removing that line, and instead binding the camera.stop_preview() to an event (such as a key press). This could look like:

root.bind("<space>", lambda e: camera.stop_preview())

Where root is what you define as your access to Tk(). lambda e: specifies an inline function expression, where e is the event object passed.

How to make a video using raspberry pi camera without it crashing

You'll probably need to use with to ensure the camera resources get properly released.

@app.route('/')
def index():
with PiCamera() as camera:
# camera.start_preview()
camera.start_recording('/home/pi/Desktop/play.h264')
sleep(15)
camera.stop_recording()
# camera.stop_preview()
return "OK"

If that doesn't help, there are some points about the pi camera's hardware limits here.

Capture video from camera on Raspberry Pi and filter in OpenGL before encoding

The texture conversion will work on any MMAL opaque buffer i.e. camera preview, still (up to 2000x2000 resolution), video. However, the example code only does the GL plumbing for stills preview. I think someone posted a patch on the RPI forums to make it work with RaspiVid so you might be able to use that.

Fastpath basically means not copying the buffer data to ARM memory and doing a software conversion. So, for the GL rendering it means just passing a handle to GL so the GPU driver can do this directly.

Currently, there is no support/fastpath in the drivers for feeding the OpenGL rendered buffers into the video encoder. Instead, the slow and probably impractical path is to call glReadPixels, convert the buffer to YUV and pass the converted buffer to the encoder.

A fastpath is certainly possible and I've done some work in porting this to the RPI drivers but there's some other framework required and I won't get chance to look at this until the New Year.



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