(Vibrante) NvMedia Camera Capture Sample App

NvMedia Camera Capture Sample user guide.

Introduction

Note

This sample is available for Vibrante platform only.

nvx_sample_nvmedia_camera demonstrates frame grabbing from 1, 2, or 4 CSI cameras with NvMedia API and basic VisionWorks-NvMedia interop facilities. As a basic VisionWorks processing step, histogram equalization is used. Histogram equalization is applied to the inner sub-rectangle only to make the effect of equalization more obvious. The sample is tested with four OV10635 and OV10640 CSI cameras.

After VisionWorks installation, nvx_sample_nvmedia_camera is installed in the following directory:

/usr/share/visionworks/sources/samples/nvmedia_camera

For the steps to build sample applications, see the Linux: Building and Running Samples and Demos section.

The sample organization on the global level is illustrated by the flowchart:

• For Omni Vision 10635 cameras:

     [Capture2D step: output is YUV422]
                     |
     [Convertion YUV422 to RGBA step]
                     |
                [EGLStream]
                     |
         [VisionWorks RGBX to NV12]
                     |
[VisionWorks Histogram Equalization of Y plane]
                     |
         [VisionWorks NV12 to RGBX]
                     |
             [NVXIO Rendering]

• For Omni Vision 10640 cameras:

     [Capture2D step: output is RAW12]
                     |
[NvMedia IPP post-processing: output is NV12]
                     |
                [EGLStream]
                     |
         [VisionWorks RGBX to NV12]
                     |
[VisionWorks Histogram Equalization of Y plane]
                     |
         [VisionWorks NV12 to RGBX]
                     |
             [NVXIO Rendering]

The sample builds the chain of hardware-based NvMedia image processing steps that are executed in a dedicated thread for each active camera. Thread communication is based on queues without actual data copying. Communication between the NvMedia step and VisionWorks is implemented with the EGLStream EGL extension. The main thread implements histogram equalization and then rendering to exclude EGL and OpenVX context sharing between threads.

Attaching the Cameras

Cameras must be attached to the correct port to work. The following images illustrate the camera connections.

Note

There are multiple CSI connectors on the board. You must connect cameras in the correct order:

• For Jetson Pro, connect in ascending order starting from connector 0.
• For NVIDIA^® DRIVE™ PX, attach the connectors in reverse order as shown in the DRIVE PX picture below.

For more details, see the Platform Quick Start for your board.

DRIVE PX Camera Connections

DRIVE PX provides multiple video and camera ports. Before using these cameras with the NvMedia sample applications, you must attach the cameras to the ports in a specific order. If you fail to do so, NvMedia raises errors.

Warning

Before connecting/disconnecting cameras to/from the platform, remove power. Failure to do so may damage the platform.

DRIVE PX Camera Interfaces

DRIVE PX provides GMSL, USB, and Ethernet camera interfaces. The GMSL camera interfaces:

• Provide 12 simultaneous GMSL camera inputs
• Route camera data to both Tegras
• Control any camera from either Tegra
• Synchronize cameras within each group

Mapping Connectors to Tegra Chips

Each GMSL camera group can be routed to one or both Tegra chips via a GMSL Deserializer.

Connecting Cameras to DRIVE PX

When you connect cameras to a specific camera group, you must attach the cameras in sequential order. For example, within Group A:

• Attach the first camera to A0.
• If used, attach the second camera to A1.
• If used, attach the second camera to A2.
• If used, attach the second camera to A3.

If you fail to attach cameras in this order, NvMedia generates an error message.

Default Aggregator Link Mapping

The following diagram shows how the digitized camera pictures are aggregated into a frame, where the image from the first camera appears first in the frame and the image from the last camera appears last in the frame. The frame size changes depending on how many cameras are connected.

All the sample applications that process images provide a aggregate n option to specify the number of aggregated images in the frame. In this option, n maps as follows:

• n=1 maps to link0
• n=2 maps to link0 and link1
• etc.
• n=4 maps to all links

The number of cameras connected must match the number specified in the aggregate option.

Jetson TK1 Pro Camera Connections

Executing the NvMedia Camera Sample

• On Jetson TK1 Pro with 2 OV10635 cameras, execute:

    $ ./nvx_sample_nvmedia_camera -c dvp-ov10635-yuv422-ab -n 2
  

• On DRIVE PX B00 with 2 OV10635 cameras, execute:

    $ ./nvx_sample_nvmedia_camera -c dvp-ov10635-yuv422-ab-e2379 -n 2
  

• On DRIVE PX B00 with 4 OV10640 cameras, execute:

    $ ./nvx_sample_nvmedia_camera -c dvp-ov10640-raw12-ab-e2379 -n 4
  

Command Line Options

This topic provides a list of supported options and the values they consume.

-c, --camera

• Parameter: [Camera hardware configuration name]
• Description: Specifies the configuration name that describes the current camera setup.
• Usage: --camera="dvp-ov10635-yuv422-ab"

-n, --camera_number

• Parameter: [Number of connected cameras]
• Description: Specifies the number of connected cameras. 1, 2, or 4 cameras are supported.
• Usage: --camera_number=4

-h, --help

• Description: Prints the help message.

Operational Keys

• Use Space to toggle histogram equalization mode.
• Use ESC to close the sample.