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| -rwxr-xr-x | src/py/examples/simple-continuous-capture.py | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/src/py/examples/simple-continuous-capture.py b/src/py/examples/simple-continuous-capture.py new file mode 100755 index 00000000..fe78a2dd --- /dev/null +++ b/src/py/examples/simple-continuous-capture.py @@ -0,0 +1,191 @@ +#!/usr/bin/env python3 + +# SPDX-License-Identifier: BSD-3-Clause +# Copyright (C) 2022, Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> + +# A simple capture example extending the simple-capture.py example: +# - Capture frames using events from multiple cameras +# - Listening events from stdin to exit the application +# - Memory mapping the frames and calculating CRC + +import binascii +import libcamera as libcam +import libcamera.utils +import selectors +import sys + + +# A container class for our state per camera +class CameraCaptureContext: + idx: int + cam: libcam.Camera + reqs: list[libcam.Request] + mfbs: dict[libcam.FrameBuffer, libcamera.utils.MappedFrameBuffer] + + def __init__(self, cam, idx): + self.idx = idx + self.cam = cam + + # Acquire the camera for our use + + ret = cam.acquire() + assert ret == 0 + + # Configure the camera + + cam_config = cam.generate_configuration([libcam.StreamRole.Viewfinder]) + + stream_config = cam_config.at(0) + + ret = cam.configure(cam_config) + assert ret == 0 + + stream = stream_config.stream + + # Allocate the buffers for capture + + allocator = libcam.FrameBufferAllocator(cam) + ret = allocator.allocate(stream) + assert ret > 0 + + num_bufs = len(allocator.buffers(stream)) + + print(f'cam{idx} ({cam.id}): capturing {num_bufs} buffers with {stream_config}') + + # Create the requests and assign a buffer for each request + + self.reqs = [] + self.mfbs = {} + + for i in range(num_bufs): + # Use the buffer index as the "cookie" + req = cam.create_request(idx) + + buffer = allocator.buffers(stream)[i] + ret = req.add_buffer(stream, buffer) + assert ret == 0 + + self.reqs.append(req) + + # Save a mmapped buffer so we can calculate the CRC later + self.mfbs[buffer] = libcamera.utils.MappedFrameBuffer(buffer).mmap() + + def uninit_camera(self): + # Stop the camera + + ret = self.cam.stop() + assert ret == 0 + + # Release the camera + + ret = self.cam.release() + assert ret == 0 + + +# A container class for our state +class CaptureContext: + cm: libcam.CameraManager + camera_contexts: list[CameraCaptureContext] = [] + + def handle_camera_event(self): + # cm.get_ready_requests() will not block here, as we know there is an event + # to read. + + reqs = self.cm.get_ready_requests() + + # Process the captured frames + + for req in reqs: + self.handle_request(req) + + return True + + def handle_request(self, req: libcam.Request): + cam_ctx = self.camera_contexts[req.cookie] + + buffers = req.buffers + + assert len(buffers) == 1 + + # A ready Request could contain multiple buffers if multiple streams + # were being used. Here we know we only have a single stream, + # and we use next(iter()) to get the first and only buffer. + + stream, fb = next(iter(buffers.items())) + + # Use the MappedFrameBuffer to access the pixel data with CPU. We calculate + # the crc for each plane. + + mfb = cam_ctx.mfbs[fb] + crcs = [binascii.crc32(p) for p in mfb.planes] + + meta = fb.metadata + + print('cam{:<6} seq {:<6} bytes {:10} CRCs {}' + .format(cam_ctx.idx, + meta.sequence, + '/'.join([str(p.bytes_used) for p in meta.planes]), + crcs)) + + # We want to re-queue the buffer we just handled. Instead of creating + # a new Request, we re-use the old one. We need to call req.reuse() + # to re-initialize the Request before queuing. + + req.reuse() + cam_ctx.cam.queue_request(req) + + def handle_key_event(self): + sys.stdin.readline() + print('Exiting...') + return False + + def capture(self): + # Queue the requests to the camera + + for cam_ctx in self.camera_contexts: + for req in cam_ctx.reqs: + ret = cam_ctx.cam.queue_request(req) + assert ret == 0 + + # Use Selector to wait for events from the camera and from the keyboard + + sel = selectors.DefaultSelector() + sel.register(sys.stdin, selectors.EVENT_READ, self.handle_key_event) + sel.register(self.cm.event_fd, selectors.EVENT_READ, lambda: self.handle_camera_event()) + + running = True + + while running: + events = sel.select() + for key, mask in events: + # If the handler return False, we should exit + if not key.data(): + running = False + + +def main(): + cm = libcam.CameraManager.singleton() + + ctx = CaptureContext() + ctx.cm = cm + + for idx, cam in enumerate(cm.cameras): + cam_ctx = CameraCaptureContext(cam, idx) + ctx.camera_contexts.append(cam_ctx) + + # Start the cameras + + for cam_ctx in ctx.camera_contexts: + ret = cam_ctx.cam.start() + assert ret == 0 + + ctx.capture() + + for cam_ctx in ctx.camera_contexts: + cam_ctx.uninit_camera() + + return 0 + + +if __name__ == '__main__': + sys.exit(main()) |