Very low recording frame rate

[leroycorentin]

Hi,
I am working with a Syslogic RPC RS A4NA (that has a Jetson Orin Nano and a Apacer NVMe SSD of sequential write speed 1115 Mb/s) with L4T R35.4.1, a single ZED X camera connected by a 50cm GMSL2 cable, and ZED SDK 5.0.0. My power mode is the maximum one (0, with 10W) and I am running jetson_clocks.

I can visualize the video and depth of the camera using the ZED tools properly with a frame rate of up to 60fps for the video (whatever the resolution) and 8-10Hz for the depth data, as displayed on ZED_Explorer/ZED_Depth_Viewer.

However, when I try to record the data, the frame rate drops drastically. I have tried using ROS2 and native ZED tools or samples. My end goal is to record ROS2 bags with RGB images (video), depth map, point cloud and IMU at least.

Apparently, the Jetson Orin Nano does not allow software H264 encoding in real-time, so I cannot record svo files with compression.
With ZED_Explorer or with the recording/recording/mono/cpp sample (after having modified the code to change the compression mode to “losseless”), whenever I record a svo file, it is then seen as corrupted or invalid by all ZED tools, and I have to use the ZED_SVO_Editor tool to repair it. (Any idea why?) When I read it, the ZED_Explorer tool, for example, gives me a frame rate of ~14fps at most.

Using a ROS2 docker with the proper Cyclone DDS tuning (following your guide), I get an even lower frame rate. ros2 topic hz or rqt topic monitoring tool give me ~4.5Hz with the default parameters. When there is no subscriber, ros2 topic hz gives me 30Hz, but as soon as there is a subscriber, whatever the type (ros2 topic echo / ros2 bag record / rqt_bag / rqt topic monitoring tool / Foxglove), it lowers directly to ~4.5Hz. (rqt topic monitoring tool always shows this value, even if there is no other subscriber.) If I reduce the resolution to 1080, I get 5.5Hz, and if I set the depth mode to ‘NONE’ I get 5.7Hz, not higher.
I have tried monitoring topic rates from a remote PC or on the host Syslogic PC, with no impact.

Why can’t I get better performances with the ZED X camera?

Attached are the results from the ZED_Diagnostic tool:
dmesg.log (46.9 KB)
ZED_Diagnostic_Results.json (62.4 KB)

[Myzhar]

@leroycorentin

However, when I try to record the data, the frame rate drops drastically. I have tried using ROS2 and native ZED tools or samples. My end goal is to record ROS2 bags with RGB images (video), depth map, point cloud and IMU at least.

I recommend recording SVO2 files using ZED Explorer instead of directly recording rosbags.
Then, on a powerful PC, you use the SVO2 file as input for the ZED ROS2 wrapper, and you record the rosbag from the replayed stream

@leroycorentin

Apparently, the Jetson Orin Nano does not allow software H264 encoding in real-time, so I cannot record svo files with compression.

This is correct. The Jetson Orin Nano is the only Jetson module not equipped with hardware encoders. So it’s not possible to use H.264 and H.265 compression with it.

@leroycorentin

Apparently, the Jetson Orin Nano does not allow software H264 encoding in real-time, so I cannot record svo files with compression.
With ZED_Explorer or with the recording/recording/mono/cpp sample (after having modified the code to change the compression mode to “losseless”), whenever I record a svo file, it is then seen as corrupted or invalid by all ZED tools, and I have to use the ZED_SVO_Editor tool to repair it. (Any idea why?) When I read it, the ZED_Explorer tool, for example, gives me a frame rate of ~14fps at most.

The ZED SDK v5.0.2 GA, released yesterday, is expected to resolve this issue.

@leroycorentin

Using a ROS2 docker with the proper Cyclone DDS tuning (following your guide), I get an even lower frame rate.

Docker always introduces a little performance loss.

@leroycorentin

When there is no subscriber, ros2 topic hz gives me 30Hz, but as soon as there is a subscriber, whatever the type (ros2 topic echo / ros2 bag record / rqt_bag / rqt topic monitoring tool / Foxglove), it lowers directly to ~4.5Hz. (rqt topic monitoring tool always shows this value, even if there is no other subscriber.)

This is caused by memory copy on big data. Try reducing the resolution and framerate.

@leroycorentin

If I reduce the resolution to 1080, I get 5.5Hz, and if I set the depth mode to ‘NONE’ I get 5.7Hz, not higher.

It’s not a depth processing problem because it’s performed on the GPU. Memory copy happens on the CPU.

@leroycorentin

Why can’t I get better performances with the ZED X camera?

Remember that the Jetson Orin Nano is not as powerful as an Orin NX or AGX Orin.
You can have an idea by compating the depth extraction performance here.