Save video instead of saving images while using basler camera and python

Question

I'm using Basler camera and python to record some video. I can successfully capture individual frames, but I don't know how to record a video.

Following is my code:

import os
import pypylon
from imageio import imwrite
import time
start=time.time()

print('Sampling rate (Hz):')
fsamp = input()
fsamp = float(fsamp)

time_exposure = 1000000*(1/fsamp)

available_cameras = pypylon.factory.find_devices()
cam = pypylon.factory.create_device(available_cameras[0])
cam.open()

#cam.properties['AcquisitionFrameRateEnable'] = True
#cam.properties['AcquisitionFrameRate'] = 1000
cam.properties['ExposureTime'] = time_exposure

buffer = tuple(cam.grab_images(2000))
for count, image in enumerate(buffer):
    filename = str('I:/Example/{}.png'.format(count))
    imwrite(filename, image)
del buffer

Answer 1

I haven't found a way to record a video using pypylon ; it seems to be a pretty light wrapper around Pylon. However, I have found a way to save a video using imageio :

from imageio import get_writer
with get_writer('I:/output-filename.mp4', fps=fps) as writer:
    # Some stuff with the frames

The above can be used with .mov , .avi , .mpg , .mpeg , .mp4 , .mkv or .wmv , so long as the FFmpeg program is available. How you will install this program depends on your operating system. See this link for details on the parameters you can use .

Then, simply replace the call to imwrite with:

writer.append_data(image)

ensuring that this occurs in the with block.

An example implementation:

import os
import pypylon
from imageio import get_writer

while True:
    try:
        fsamp = float(input('Sampling rate (Hz): '))
        break
    except ValueError:
        print('Invalid input.')

time_exposure = 1000000 / fsamp

available_cameras = pypylon.factory.find_devices()
cam = pypylon.factory.create_device(available_cameras[0])
cam.open()

cam.properties['ExposureTime'] = time_exposure

buffer = tuple(cam.grab_images(2000))
with get_writer(
       'I:/output-filename.mkv',  # mkv players often support H.264
        fps=fsamp,  # FPS is in units Hz; should be real-time.
        codec='libx264',  # When used properly, this is basically
                          # "PNG for video" (i.e. lossless)
        quality=None,  # disables variable compression
        pixelformat='rgb24',  # keep it as RGB colours
        ffmpeg_params=[  # compatibility with older library versions
            '-preset',  # set to faster, veryfast, superfast, ultrafast
            'fast',     # for higher speed but worse compression
            '-crf',  # quality; set to 0 for lossless, but keep in mind
            '11'     # that the camera probably adds static anyway
        ]
) as writer:
    for image in buffer:
        writer.append_data(image)
del buffer