video_cap.py

import sys
import cPickle
import datetime
import cv2
import boto3
import time
import cPickle
from multiprocessing import Pool
import pytz

kinesis_client = boto3.client("kinesis")
rekog_client = boto3.client("rekognition")

camera_index = 0 # 0 is usually the built-in webcam
capture_rate = 30 # Frame capture rate.. every X frames. Positive integer.
rekog_max_labels = 123
rekog_min_conf = 50.0

#Send frame to Kinesis stream
def encode_and_send_frame(frame, frame_count, enable_kinesis=True, enable_rekog=False, write_file=False):
    try:
        #convert opencv Mat to jpg image
        #print "----FRAME---"
        retval, buff = cv2.imencode(".jpg", frame)

        img_bytes = bytearray(buff)

        utc_dt = pytz.utc.localize(datetime.datetime.now())
        now_ts_utc = (utc_dt - datetime.datetime(1970, 1, 1, tzinfo=pytz.utc)).total_seconds()

        frame_package = {
            'ApproximateCaptureTime' : now_ts_utc,
            'FrameCount' : frame_count,
            'ImageBytes' : img_bytes
        }

        if write_file:
            print("Writing file img_{}.jpg".format(frame_count))
            target = open("img_{}.jpg".format(frame_count), 'w')
            target.write(img_bytes)
            target.close()

        #put encoded image in kinesis stream
        if enable_kinesis:
            print "Sending image to Kinesis"
            response = kinesis_client.put_record(
                StreamName="Frame-Stream",
                Data=cPickle.dumps(frame_package),
                PartitionKey="partitionkey"
            )
            print response

        if enable_rekog:
            response = rekog_client.detect_labels(
                Image={
                    'Bytes': img_bytes
                },
                MaxLabels=rekog_max_labels,
                MinConfidence=rekog_min_conf
            )
            print response

    except Exception as e:
        print e


def main():

    argv_len = len(sys.argv)

    if argv_len > 1 and sys.argv[1].isdigit():
        global capture_rate
        capture_rate = int(sys.argv[1])

    cap = cv2.VideoCapture(0) #Use 0 for built-in camera. Use 1, 2, etc. for attached cameras.
    pool = Pool(processes=3)

    frame_count = 0
    while True:
        # Capture frame-by-frame
        ret, frame = cap.read()
        #cv2.resize(frame, (640, 360));

        if ret is False:
            break

        if frame_count % capture_rate == 0:
            result = pool.apply_async(encode_and_send_frame, (frame, frame_count, True, False, False,))

        frame_count += 1

        # Display the resulting frame
        cv2.imshow('frame', frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break

    # When everything done, release the capture
    cap.release()
    cv2.destroyAllWindows()
    return

if __name__ == '__main__':
    main()