Can SVO2 recording and other tasks obtain image data at the same time?

[byhang]

Preliminary Checks

• This issue is not a duplicate. Before opening a new issue, please search existing issues.
• This issue is not a question, bug report, or anything other than a feature request directly related to this project.

Proposal

Hi, I want to ensure that other programs using zed2i camera data are not affected during the svo2 recording process.

Use-Case

zed_cam.enable_recording(recordingParameters)
while True:
    if zed_cam.grab(runtime) == sl.ERROR_CODE.SUCCESS :  # recording
        zed_cam.retrieve_image(left_image, sl.VIEW.LEFT)           # get image data for orther task
        zed_cam.retrieve_image(right_image, sl.VIEW.RIGHT)
        zed_cam.retrieve_measure(depth_map, sl.MEASURE.DEPTH)
        # But I got "**Segmentation fault (core dumped)**"

Anything else?

Is there any way I can achieve both of these tasks at the same time?

[byhang]

This feature is very important for me, looking forward to your reply.

[obraun-sl]

Hi. Yes this is possible to have the recording + data acquisition in the same time/process.

Can you share the parameters you use for initparameters, recordingparameters and runtimeparameters to ensure there is no conflict.

[byhang]

@obraun-sl Sounds great. Could you elaborate a little bit? and give an python example?

[obraun-sl]

Yes you can share the python or c++ script here, to get the full overview

[byhang]

    # Set configuration parameters for the zed
    init = sl.InitParameters()
    # This parameter can be used to record SVO in camera FPS even if the grab loop is running at a lower FPS (due to compute for ex.)
    init.async_image_retrieval = False
    init.camera_resolution = sl.RESOLUTION.HD720
    init.camera_fps = 30
    status = zed_cam.open(init)
    if status != sl.ERROR_CODE.SUCCESS:
        print("Camera Open", status, "Exit program.")
        exit(1)
    # Enable recording with the filename specified in argument
    recordingParameters = sl.RecordingParameters()
    recordingParameters.compression_mode = sl.SVO_COMPRESSION_MODE.H264
    recordingParameters.bitrate = 2500
    recordingParameters.video_filename = cfg['output_dir'] + '/' + datetime.now().strftime("%Y%m%d_%H%M%S") + '.svo2'
    err = zed_cam.enable_recording(recordingParameters)
    if err != sl.ERROR_CODE.SUCCESS:
        print("Recording zed : ", err)
        exit(1)

    runtime = sl.RuntimeParameters()
    # Start recording SVO, stop with Ctrl-C command
    print("SVO is Recording, use Ctrl-C to stop.")
    frames_recorded = 0
    left_image = sl.Mat()
    right_image = sl.Mat()
    while True:
        # Check that a new image is successfully acquired
        if zed_cam.grab(runtime) == sl.ERROR_CODE.SUCCESS :
            # Segmentation fault (core dumped) here
            zed_cam.retrieve_image(left_image, sl.VIEW.LEFT)
            zed_cam.retrieve_image(right_image, sl.VIEW.RIGHT)
            frames_recorded += 1
            print("Frame count: " + str(frames_recorded), end="\r")

[byhang]

init.async_image_retrieval = False should be True?

[byhang]

init.async_image_retrieval = False should be True?

It works when setting True. :-)
I set False, got "[ZED][ERROR] [ZED] sl::Camera::Open has not been called, no Camera instance running."，didn't expect it to be async_image_retrieval's problem.
What does async_image_retrieval do and why does it affect image retrieval?