12_camera_v4l2_cuda

• Overview
• Building and Running
• Flow
• Key Structure and Functions

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Overview

This sample demonstrates how to capture images from a V4L2 YUV type of camera and share the image stream with NVIDIA^® CUDA^® engines to draw a black box on the upper left corner.

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Building and Running

Prerequisites

• You have followed Steps 1-3 in Building and Running.
• If you are building from your host Linux PC (x86), you have followed Step 4 in Building and Running.
• You have the following hardware:
  • V4L2 Camera (USB or YUV Camera with the format YUYV/YVYU/UYVY/VYUY)
  • Display

To build:

• Enter:

    $ cd 12_camera_v4l2_cuda
    $ make
  

To run

• Enter:

    $ ./camera_v4l2_cuda -d /dev/video0 -s 1280x720 -f YUYV -c
  

  The -c option enables CUDA processing.

• Or enter:

    $ ./camera_v4l2_cuda -d /dev/video0 -s 640x480 -f YUYV -n 30 -c
  

  The -n option saves the n-th frame before video converter processing.

To view supported options

• Use the -h option.

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Flow

The following diagram shows the flow of data through this sample.

Block Diagram

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Key Structure and Functions

The sample defines the structure and functions listed in the following tables.

Structure	Description
context_t	Global structure to save the context for V4L2 camera, VIC, CUDA and EglRenderer.

Function	Description
init_components	Initializes V4L2 camera, VIC, and EglRenderer.
prepare_buffers	Allocates buffers for VIC output_plane and capture_plane. Then, it shares the buffers with V4L2 Camera, CUDA, and EglRenderer.
start_stream	Starts V4L2 camera streaming and VIC.
conv_capture_dqbuf_thread_callback	Processes the de-queued buffer with CUDA and renders it to the display.
start_capture	Main thread to enqueue and dequeue buffers.
stop_stream	Stops V4L2 camera streaming.