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