Image display API

The following image display APIs can be used with Jetson.

・GStreamer video sink plugin

・OpenCV High-level GUI

・Rendering API provided by Multimedia API

・X11 + OpenGL ES

・NVIDIA Tegra Direct Rendering Manager (DRM)

Each feature is summarized in the table below.

When using GStreamer's video sink plugin

The table below summarizes the video sink plugins that can display image data on NVMM memory (DMA buffers, which can be transferred between hardware modules).

Plug-ins such as xvimagesink can also be used to display image data on the CPU memory.

When using OpenCV High-level GUI

Image data can be displayed with the imshow function.

Below is a programming example with the OpenCV Python API.

import cv2 import sys cam_id = 0 cap = cv2.VideoCapture(cam_id) if not cap.isOpened(): print("Cannot open camera") sys.exit() while True: ret, frame = cap.read() cv2.imshow("Test", frame) key = cv2.waitKey(1) if key == 27: # ESC break cv2.destroyAllWindows() cap.release() sys.exit()

When using Rendering API provided by Multitimedia API

You can see how to use the Rendering API in the image display part of the V4L2 sample code included in JetPack. This sample code exists in the following path.

/usr/src/jetson_multimedia_api/samples/12_camera_v4l2_cuda

When using X11 + OpenGL ES

The user implements the processing that the Rendering API described above is doing internally. The Rendering API source code is helpful.

/usr/src/jetson_multimedia_api/samples/common/classes/NvEglRenderer.cpp

You can also refer to the following sample code.

/usr/src/jetson_multimedia_api/argus/samples/eglImage

When using NVIDIA Tegra Direct Rendering Manager (DRM)

Please refer to the 08_video_dec_drm sample code provided in the Multimedia API package. Note that this sample code needs to be run after disabling Jetson's Ubuntu desktop. See the instructions on the linked page above for how to do this. The path of the sample code is as follows.

/usr/src/jetson_multimedia_api/samples/08_video_dec_drm

Next time, I will explain how to encode the video!

How did you like the 5th episode of the series "Jetson Video Processing Programming", which introduced how to display the captured image and its processing result image on the display?

Next time, I will introduce how to encode the video.

If you have any questions, please feel free to contact us.

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