> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Encode and decode video with qrb_ros_video

> qrb_ros_video is a ROS package that provides hardware-accelerated video processing for Qualcomm robotics platforms.

The `qrb_ros_video` sample application provides the following features:

* Hardware-accelerated H.264/H.265 video encoding and decoding using the Qualcomm video processing unit (VPU)

* Zero-copy memory management for high-performance video processing

* Integration with ROS 2 ecosystem and camera pipelines

* Support for real-time video streaming and file I/O operations

## Pipeline flow for `qrb_ros_video`

The following figure shows the pipeline flow for `qrb_ros_video`.

<Frame caption="The qrb_ros_video pipeline.">
  <img src="https://mintcdn.com/qualcomm-prod/EDJV-hu6qJhZi4pm/SDKs/QIR-SDK-Ubuntu/images/image21.png?fit=max&auto=format&n=EDJV-hu6qJhZi4pm&q=85&s=698007e54159c2d72a0a2a0d925a117d" alt="Camera node, image reader, and compressed reader feeding the encoder and decoder nodes, which output to the compressed writer, image writer, and display." width="1948" height="399" data-path="SDKs/QIR-SDK-Ubuntu/images/image21.png" />
</Frame>

* **Video encoder node**: Converts raw images to compressed H.264/H.265 streams using Qualcomm VPU hardware.

* **Video decoder node**: Decodes compressed video streams back to raw image frames.

* **Camera support**: Accepts input from the QRB ROS Camera package with zero-copy transport.

* **File I/O components**: Implements `CompressedWriter` and `ImageWriter` for saving video data to files.

* **Hardware acceleration**: Leverages Qualcomm Video Processing Unit (VPU) for efficient encoding/decoding.

* **Memory management**: Uses DMA buffers and `qrb_ros_transport` for zero-copy operations.

## `qrb_ros_video` APIs

The `qrb_ros_video` node exposes ROS interfaces and ROS parameters. Use them to feed frames to the encoder or decoder and to configure the video format.

### ROS interfaces

The following table lists the encoder topics, with the message type and content of each topic.

| Topic     | Message type                        | Description                         |
| --------- | ----------------------------------- | ----------------------------------- |
| `/input`  | `qrb_ros::transport::type::Image`   | Uncompressed YUV frames             |
| `/output` | `sensor_msgs::msg::CompressedImage` | Compressed H.264/H.265 video stream |

The following table lists the decoder topics, with the message type and content of each topic.

| Topic     | Message type                        | Description                                                   |
| --------- | ----------------------------------- | ------------------------------------------------------------- |
| `/input`  | `sensor_msgs::msg::CompressedImage` | Indicates the input of a compressed H.264/H.265 video stream. |
| `/output` | `qrb_ros::transport::type::Image`   | Indicates the output decoded YUV frames.                      |

### ROS parameters

The following table lists the video encoder parameters, with the type, default value, and purpose of each parameter.

| Parameter      | Type     | Default    | Description                              |
| -------------- | -------- | ---------- | ---------------------------------------- |
| `format`       | `string` | `h264`     | Video codec format (`h264`/`h265`)       |
| `pixel_format` | `string` | `nv12`     | Input pixel format (`nv12`/`p010`)       |
| `width`        | `int`    | `1920`     | Video width                              |
| `height`       | `int`    | `1080`     | Video height                             |
| `framerate`    | `int`    | `30`       | Frames per second                        |
| `bitrate`      | `int`    | `5000000`  | Target bit rate in bits/second           |
| `rate_control` | `string` | `variable` | Rate control mode (`variable`/`cbr`)     |
| `profile`      | `string` | `main`     | Codec profile (`baseline`/`main`/`high`) |
| `level`        | `string` | `4.1`      | Codec level                              |

The following table lists the video decoder parameters, with the type, default value, and purpose of each parameter.

| Parameter      | Type     | Default | Description                        |
| -------------- | -------- | ------- | ---------------------------------- |
| `format`       | `string` | `h264`  | Indicates the input codec format.  |
| `pixel-format` | `string` | `nv12`  | Indicates the output pixel format. |

## Prerequisites

* You have set up the device, installed ROS2 Jazzy and the Qualcomm Intelligent Robotics (QIR) SDK on the device according to [Install the QIR SDK](./install-the-qir-sdk).

* You have connected the device to the display monitor.

## Run out-of-the-box `qrb_ros_video`

<Steps>
  <Step title="Install the qrb_ros_video packages">
    ```bash Install the packages theme={null}
    sudo apt install ros-jazzy-qrb-ros-video ros-jazzy-qrb-ros-video-test
    ```
  </Step>

  <Step title="Start the local video file recording">
    ```bash Start the encoder theme={null}
    mkdir -p /data
    sudo chmod 777 /data
    source /opt/ros/jazzy/setup.bash
    # push YUV sample file 1920_1080_nv12.yuv to /data/ directory
    scp <path of 1920_1080_nv12.yuv> IP@ubuntu:/home/ubuntu
    sudo mv /home/ubuntu/1920_1080_nv12.yuv /data
    ros2 launch qrb_ros_video encoder_launch.py
    ```
  </Step>

  <Step title="Start the local video file playback">
    ```bash Start the decoder theme={null}
    mkdir -p /data
    sudo chmod 777 /data
    source /opt/ros/jazzy/setup.bash
    # push YUV sample file 1920_1080.mp4 to /data/ directory
    scp <path of 1920_1080.mp4> IP@ubuntu:/home/ubuntu
    sudo mv /home/ubuntu/1920_1080.mp4 /data
    ros2 launch qrb_ros_video decoder_launch.py
    ```
  </Step>
</Steps>

## Build from source

<Steps>
  <Step title="Install dependencies">
    ```bash Install the dependencies theme={null}
    sudo apt install build-essential cmake pkg-config
    # Install GStreamer development packages
    sudo apt install libgstreamer1.0-dev libgstreamer-plugins-base1.0-devs
    # Install ROS2 Jazzy (if not already installed)
    # Follow instructions at https://docs.ros.org/en/jazzy/Installation.html
    sudo apt install ros-jazzy-rclcpp ros-jazzy-rclcpp-components ros-jazzy-ament-cmake-auto ros-jazzy-std-msgs ros-jazzy-sensor-msgs ros-jazzy-qrb-ros-transport-image-type
    ```
  </Step>

  <Step title="Download the source code and build with colcon">
    ```bash Build the package theme={null}
    source /opt/ros/jazzy/setup.bash
    git clone https://github.com/qualcomm-qrb-ros/qrb_ros_video qrb_ros_video
    colcon build --packages-select qrb_ros_video
    ```
  </Step>

  <Step title="Run and debug">
    ```bash Run the encoder theme={null}
    source install/setup.bash
    # push YUV sample file 1920_1080_nv12.yuv to /data/ directory
    ros2 launch qrb_ros_video encoder_launch.py
    ```
  </Step>
</Steps>