isaac_ros_h264_decoder

Source code on GitHub.

Quickstart

This quickstart shows an example of how to use the isaac_ros_h264_decoder with a pre-recorded rosbag, which contains compressed H.264 images generated from isaac_ros_h264_encoder with two Argus cameras as the input source. You will be able to visualize the decoded images after the last step.

1. Set up your development environment by following the instructions here.

2. Clone isaac_ros_common and this repository under ${ISAAC_ROS_WS}/src.

   cd ${ISAAC_ROS_WS}/src
   

   git clone https://github.com/NVIDIA-ISAAC-ROS/isaac_ros_common.git
   

git clone https://github.com/NVIDIA-ISAAC-ROS/isaac_ros_compression.git

3. Pull down a rosbag of sample data:

   cd ${ISAAC_ROS_WS}/src/isaac_ros_compression && \
   git lfs pull -X "" -I "resources/rosbags/h264_compressed_sample.bag"
   

4. Launch the Docker container using the run_dev.sh script:

   cd ${ISAAC_ROS_WS}/src/isaac_ros_common && \
   ./scripts/run_dev.sh
   

5. Install this package’s dependencies.

   sudo apt-get install -y ros-humble-isaac-ros-h264-decoder
   

6. Run the following launch files to run the demo of this isaac_ros_h264_decoder:

   ros2 launch isaac_ros_h264_decoder isaac_ros_h264_decoder_rosbag.launch.py rosbag_path:=/workspaces/isaac_ros-dev/src/isaac_ros_compression/resources/rosbags/h264_compressed_sample.bag
   

7. Open a second terminal and attach to the container:

   cd ${ISAAC_ROS_WS}/src/isaac_ros_common && \
   ./scripts/run_dev.sh
   

8. Visualize and validate the output of the package:

   ros2 run image_view image_view --ros-args -r image:=/left/image_uncompressed
   

   ros2 run image_view image_view --ros-args -r image:=/right/image_uncompressed
   

Try More Examples

To continue your exploration, check out the following suggested examples:

• Tutorial with Compatible Decoder

Troubleshooting

Symptom

Launching the decoder node using ros2 launch isaac_ros_h264_decoder isaac_ros_h264_decoder_rosbag.launch.py, produces the below error message:

x86_64 Platform:

[component_container_mt-2] 2023-04-04 22:19:02.609 WARN  /workspaces/isaac_ros-dev/ros_ws/src/isaac_ros_compression/isaac_ros_h264_decoder/gxf/codec/components/decoder.cpp@310: Decoder output is empty, current frame will be dropped

Jetson Platform:

[component_container_mt-2] 2023-04-04 06:39:57.766 WARN  gxf/std/greedy_scheduler.cpp@235: Error while executing entity 20 named 'KIWPUYFVJT_decoder_response': GXF_FAILURE
[component_container_mt-2] [ERROR] (/usr/src/jetson_multimedia_api/samples/common/classes/NvV4l2ElementPlane.cpp:178) <dec0> Capture Plane:Error while DQing buffer: Invalid argument
[component_container_mt-2] 2023-04-04 06:39:57.766 ERROR /workspaces/isaac_ros-dev/ros_ws/src/isaac_ros_compression/isaac_ros_h264_decoder/gxf/codec/components/decoder_request.cpp@530: Failed to dequeue buffer from capture plane
[component_container_mt-2] 2023-04-04 06:39:57.766 ERROR gxf/std/entity_executor.cpp@509: Failed to tick codelet  in entity: KIWPUYFVJT_decoder_response code: GXF_FAILURE
[component_container_mt-2] 2023-04-04 06:39:57.766 ERROR gxf/std/entity_executor.cpp@203: Entity with eid 35 not found!

Solution

You may see these errors when decoder receives P-frames first. Decoder can not decode P-frames until it has received the first I-frame. You can start the decoder before playing the rosbag to avoid these errors.

API

Usage

ros2 launch isaac_ros_h264_decoder isaac_ros_h264_decoder.launch.py

ROS Parameters

ROS Topics Subscribed

ROS Topic	Interface	Description
image_compressed	sensor_msgs/CompressedImage	The H.264 compressed image

ROS Topics Published

ROS Topic	Type	Description
image_uncompressed	sensor_msgs/Image	The uncompressed image with RGB8 encoding.

Output Interpretations

1. The isaas_ros_h264_decoder package outputs a uncompressed image with the same resolution as the original image. The output image will be in RGB8 format.