在录制来自摄像机的视频时节省TTL脉冲输入时间

Question

我在树莓派上使用Raspicam录制视频，并使用以下脚本保存视频缓冲区以及每帧的时间戳：

import io
import time
import datetime as dt
from picamera import PiCamera
from threading import Thread, Event
from queue import Queue, Empty
import sys, getopt
import argparse
WIDTH  = 640
HEIGHT = 480
FRAMERATE = 30
VIDEO_STABILIZATION = True
EXPOSURE_MODE = 'night'
BRIGHTNESS = 55
CONTRAST = 50
SHARPNESS = 50
SATURATION = 30
AWB_MODE = 'off'
AWB_GAINS = 1.4
VIDEO_FILE_NAME = "cam3_output_" + str(dt.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")) + ".h264"
TIMESTAMP_FILE_NAME = "cam3_timestamp_" + str(dt.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")) + ".csv"
runningTimeHours, runningTimeMinutes, runningTimeSeconds = 0,0,0
class VideoOutput(Thread):
    def __init__(self, filename):
        super(VideoOutput, self).__init__()
        self._output = io.open(filename, 'wb', buffering=0)
        self._event = Event()
        self._queue = Queue()
        self.start()
    def write(self, buf):
        self._queue.put(buf)
        return len(buf)
    def run(self):
        while not self._event.wait(0):
            try:
                buf = self._queue.get(timeout=0.1)
            except Empty:
                pass
            else:
                self._output.write(buf)
                self._queue.task_done()
    def flush(self):
        self._queue.join()
        self._output.flush()
    def close(self):
        self._event.set()
        self.join()
        self._output.close()
    @property
    def name(self):
        return self._output.name

class TimestampOutput(object):
    def __init__(self, camera, video_filename, timestamp_filename):
        self.camera = camera
        self._video = VideoOutput(video_filename)
        self._timestampFile = timestamp_filename
        self._timestamps = []
    def write(self, buf):
        if self.camera.frame.complete and self.camera.frame.timestamp is not None:
            self._timestamps.append((
                self.camera.frame.timestamp,
                self.camera.dateTime,
                self.camera.clockRealTime
                ))
        return self._video.write(buf)
    def flush(self):
        with io.open(self._timestampFile, 'w') as f:
            f.write('GPU Times, time.time(), clock_realtimen')
            for entry in self._timestamps:
                f.write('%d,%f,%fn' % entry)
    def close(self):
        self._video.close()
parser = argparse.ArgumentParser()
parser.add_argument("-hr", "--hours", type=int, help="number of hours to record")
parser.add_argument("-m", "--minutes", type=int, help="number of minutes to record")
parser.add_argument("-s", "--seconds", type=int, help="number of seconds to record")
args = parser.parse_args()

runningTimeHours = float(args.hours)
runningTimeMinutes = float(args.minutes)
runningTimeSeconds = float(args.seconds)
totalRunningTime = runningTimeHours*60*60 + runningTimeMinutes*60 + runningTimeSeconds
with PiCamera(resolution=(WIDTH, HEIGHT), framerate=FRAMERATE) as camera:
    camera.brightness = BRIGHTNESS
    camera.contrast = CONTRAST
    camera.sharpness = SHARPNESS
    camera.video_stabilization = VIDEO_STABILIZATION
    camera.hflip = False
    camera.vflip = False
    #warm-up time to camera to set its initial settings
    time.sleep(2)
    camera.exposure_mode = EXPOSURE_MODE
    camera.awb_mode = AWB_MODE
    camera.awb_gains = AWB_GAINS
    #time to let camera change parameters according to exposure and AWB
    time.sleep(2)
    #switch off the exposure since the camera has been set now 
    camera.exposure_mode = 'off'
    output = TimestampOutput(camera, VIDEO_FILE_NAME, TIMESTAMP_FILE_NAME)
    try:
        camera.start_preview()
        # Construct an instance of our custom output splitter with a filename  and a connected socket
        print('Starting Recording')
        camera.start_recording(output, format='h264')
        print('Started Recording')
        camera.wait_recording(totalRunningTime)
        camera.stop_recording()
        camera.stop_preview()
        print('Recording Stopped')
    except KeyboardInterrupt:
        print('Closing Output File')
        sys.exit(2)
    finally:
        output.close()
        print('Output File Closed')

同时，在此录制过程中，我正在向GPIO引脚4发送TTL脉冲。我现在想在上面的脚本中添加一个代码块，以便对于收到的每个 TTL HIGH 输入，我可以将相应的时间值保存在文件中。

像这样的东西，不涉及相机运行脚本：

import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM)
pinTTL = 4
GPIO.setup(pinTTL, GPIO.IN)
while True:
    count = 0
    inputState = GPIO.input(pinTTL)
    if inputState == True:
        print 'HIGH', time.time()
GPIO.cleanup()

上述引脚状态设置为 HIGH 的脚本保存了 time.time（） 值。

基本上我想整合提到的 2 个脚本。我尝试根据 TTL 输入创建另一个线程以保存 time.time（） 值，就像我保存视频缓冲区一样，但无法让它工作。

感谢您的帮助。

Answer 1

下面的脚本对我有用。add_event_callback会自动创建一个单独的线程来处理 GPIO 事件更改。这允许将任何函数作为单独的线程调用并同时记录 TTL 时间映射。

#import the necessary modules
import io
import time
import datetime as dt
from picamera import PiCamera
from threading import Thread, Event
from queue import Queue, Empty
import sys, getopt
import argparse
import RPi.GPIO as GPIO
#camera parameter setting
WIDTH  = 640
HEIGHT = 480
FRAMERATE = 30
VIDEO_STABILIZATION = True
EXPOSURE_MODE = 'night'
BRIGHTNESS = 55
CONTRAST = 50
SHARPNESS = 50
SATURATION = 30
AWB_MODE = 'off'
AWB_GAINS = 1.4
#video, timestamps and ttl file name
VIDEO_FILE_NAME = "cam4_output_" + str(dt.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")) + ".h264"
TIMESTAMP_FILE_NAME = "cam4_timestamp_" + str(dt.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")) + ".csv"
TTL_FILE_NAME = "cam4_ttl_" + str(dt.datetime.now().strftime("%Y-%m-%d_%H-%M-%S")) + ".csv"
#running time variable intialization
runningTimeHours, runningTimeMinutes, runningTimeSeconds = 0,0,0
#set raspberry pi board layout to BCM
GPIO.setmode(GPIO.BCM)
#pin number to receive TTL input
pinTTL = 4
#set the pin as input pin
GPIO.setup(pinTTL, GPIO.IN)
#add event detection script to GPIO pin
GPIO.add_event_detect(pinTTL, GPIO.BOTH)
#video output thread to save video file
class VideoOutput(Thread):
    def __init__(self, filename):
        super(VideoOutput, self).__init__()
        self._output = io.open(filename, 'wb', buffering=0)
        self._event = Event()
        self._queue = Queue()
        self.start()
    def write(self, buf):
        self._queue.put(buf)
        return len(buf)
    def run(self):
        while not self._event.wait(0):
            try:
                buf = self._queue.get(timeout=0.1)
            except Empty:
                pass
            else:
                self._output.write(buf)
                self._queue.task_done()
    def flush(self):
        self._queue.join()
        self._output.flush()
    def close(self):
        self._event.set()
        self.join()
        self._output.close()
    @property
    def name(self):
        return self._output.name
#timestamp output object to save timestamps according to pi and TTL inputs received and write to file
class TimestampOutput(object):
    def __init__(self, camera, video_filename, timestamp_filename, ttl_filename):
        self.camera = camera
        self._video = VideoOutput(video_filename)
        self._timestampFile = timestamp_filename
        self._ttlFile = ttl_filename
        self._timestamps = []
        self._ttlTimestamps = []
    def ttlTimestampsWrite(self, input_pin):
        try:
            inputState = GPIO.input(input_pin)
            self._ttlTimestamps.append((inputState, self.camera.frame.timestamp, self.camera.dateTime, self.camera.clockRealTime))
            print(self.camera.frame.timestamp)
        except Exception as e:
            print(str(e))
            pass
    def write(self, buf):
        if self.camera.frame.complete and self.camera.frame.timestamp is not None:
            self._timestamps.append((
                self.camera.frame.timestamp,
                self.camera.dateTime,
                self.camera.clockRealTime
                ))
        return self._video.write(buf)
    def flush(self):
        with io.open(self._timestampFile, 'w') as f:
            f.write('GPU Times, time.time(), clock_realtimen')
            for entry in self._timestamps:
                f.write('%d,%f,%fn' % entry)
        with io.open(self._ttlFile, 'w') as f:
            f.write('Input State, GPU Times, time.time(), clock_realtimen')
            for entry in self._ttlTimestamps:
                f.write('%f,%f,%f,%fn' % entry)
    def close(self):
        self._video.close()
parser = argparse.ArgumentParser()
parser.add_argument("-hr", "--hours", type=int, help="number of hours to record")
parser.add_argument("-m", "--minutes", type=int, help="number of minutes to record")
parser.add_argument("-s", "--seconds", type=int, help="number of seconds to record")
args = parser.parse_args()
runningTimeHours = float(args.hours)
runningTimeMinutes = float(args.minutes)
runningTimeSeconds = float(args.seconds)
totalRunningTime = runningTimeHours*60*60 + runningTimeMinutes*60 + runningTimeSeconds
with PiCamera(resolution=(WIDTH, HEIGHT), framerate=FRAMERATE) as camera:
    camera.brightness = BRIGHTNESS
    camera.contrast = CONTRAST
    camera.sharpness = SHARPNESS
    camera.video_stabilization = VIDEO_STABILIZATION
    camera.hflip = False
    camera.vflip = False
    #warm-up time to camera to set its initial settings
    time.sleep(2)
    camera.exposure_mode = EXPOSURE_MODE
    camera.awb_mode = AWB_MODE
    camera.awb_gains = AWB_GAINS
    #time to let camera change parameters according to exposure and AWB
    time.sleep(2)
    #switch off the exposure since the camera has been set now
    camera.exposure_mode = 'off'
    output = TimestampOutput(camera, VIDEO_FILE_NAME, TIMESTAMP_FILE_NAME, TTL_FILE_NAME)
    GPIO.add_event_callback(pinTTL, output.ttlTimestampsWrite)
    try:
        camera.start_preview()
        # Construct an instance of our custom output splitter with a filename  and a connected socket
        print('Starting Recording')
        camera.start_recording(output, format='h264')
        print('Started Recording')
        camera.wait_recording(totalRunningTime)
        camera.stop_recording()
        camera.stop_preview()
        print('Recording Stopped')
    except KeyboardInterrupt:
        print('Closing Output File')
        sys.exit(2)
    except:
        output.close()
        print('exception! output file closed')
    finally:
        output.close()
        print('Output File Closed')