Test the visualization of video stream from avi/mp4 file or camera device

[nunoguedelha]

We need to better anticipate the issues that could be encountered by the Telexistence team when using the yarp-openmct tool for visualizing the cameras. For that purpose we replace the fakeframeGrabber "scrolling line" simple test image by:

• a video stream read from an AVI (or MP4) file,
• a video stream extracted from a camera device.
• the fakeframeGrabber's scrolling line but with a complex background (for instance a random colorful image) for considering the cases where less JPEG compression is possible.

[nunoguedelha]

Video Stream Read from an AVI or MP4 File

We recompile YARP with the following CMake configuration:

YARP_COMPILE_CARRIER_PLUGINS = ON
ENABLE_yarpcar_mjpeg_carrier = ON
MJPEG_AUTOCOMPRESS = ON
ENABLE_yarpmod_ffmpeg_grabber

After building is complete, we can find the ffmpeg_grabber device "ini" file ffmpeg_grabber.ini in one of the folders specified in YARP_DATA_DIRS (namely <robotology-superbuild path>/build/install/share/yarp/plugins)

We define an additional custom config file ffmpegGrabber.ini:

# read from an avi file
device ffmpeg_grabber
source testMovie2cropped.mp4
nodelay
name /icubSim/camLeftEye

Run the grabber

yarpdev --from ffmpegGrabber.ini

We then run the yarp-openmct visualizer as usual.

testMovie2cropped-on-yarpopenmct.mp4

[nunoguedelha]

CC @S-Dafarra @traversaro

[S-Dafarra]

Just to understand, what would be the expected output? Is it normal that the images are still?

[nunoguedelha]

They're actually changing, but at a very slow refresh rate because of issue #104 , which is not a transmission issue but rather a buffering issue in the open-mct viewer implementation. More precisely a problem with the Open-MCT Time conductor plugin implementation I think. I will add more details in #104 . Analysis ongoing. I will add here a lighter video example.

[nunoguedelha]

I will add here a lighter video example.

Actually it's not worth it. With a tcp connection to a yarpview I get a very smooth visualisation of the same video, without any delay.

[nunoguedelha]

fakeframeGrabber scrolling line but with a complex background

Define the custom configuration file fakeFrameGrabber_testImage.ini

device fakeFrameGrabber
name /icubSim/camLeftEye
mode line
period 50

We chose here a 50ms period for matching the same FPS rate used by the iCub cameras.

Run the grabber

yarpdev --from fakeFrameGrabber_testImage.ini --src testImageBeach.ppm

The grabber adds the scrolling line on top of the test image testImageBeach.ppm. In this case, the test image was created from a snapshot of the test movie testMovie2cropped-on-yarpopenmct.mp4 saved as a PPM image.

testImageBeach-with-scrollingLine.mp4

We could use the "time" clock mode instead of the "line" mode. Note that there is a bug in the fakeFrameGrabber since the displayed clock appears slanted.

testImageBeach-with-time.mp4

It is probably due to the fact that the image size used for displaying the clock is hardcoded and instead of being computed from the background input image.

[nunoguedelha]

video stream extracted from a camera device

Refer to Using OpenCV Grabber with YARP.