[Question] train.py: error: unrecognized arguments: --/app/livestream/allowResize=false

[Beat-in-our-hearts]

Question

Main demand: I want to run webrtc when training the robots.

I run this scripts below

python scripts/reinforcement_learning/rsl_rl/train.py --task=Isaac-Ant-v0 --livestream=2

env setting:

• ubuntu22.04
• cuda 12.1
• install by pip
• nvidia rtx 4090
• headless server

output:

usage: train.py [--help] [--hydra-help] [--version] [--cfg {job,hydra,all}] [--resolve] [--package PACKAGE] [--run] [--multirun] [--shell-completion] [--config-path CONFIG_PATH] [--config-name CONFIG_NAME] [--config-dir CONFIG_DIR] [--experimental-rerun EXPERIMENTAL_RERUN] [--info [{all,config,defaults,defaults-tree,plugins,searchpath}]] [overrides ...]
train.py: error: unrecognized arguments: --/app/livestream/allowResize=false

And I notice that class APPLauncher:

self._livestream == 2:
                self._livestream_args += [
                    "--/app/livestream/allowResize=false",
                    "--enable",
                    "omni.kit.livestream.webrtc",

this error may due to to hydra

And I try play.py:

python scripts/reinforcement_learning/rsl_rl/play.py --task=Isaac-Ant-v0 --checkpoint="./logs/rsl_rl/ant/2025-06-18_14-13-25/model_999.pt"  --livestream=2

successfully run.

[RandomOakForest]

Thank you for posting this. It doesn't seem the rsl_rl script train.py would take --livestream=2. See this doc for reference.

[tlaguz]

It looks like there is an issue with some scripts after introducing hydra. For example:

LIVESTREAM=2 ./isaaclab.sh -p scripts/tutorials/00_sim/launch_app.py --size 0.5
LIVESTREAM=2 ./isaaclab.sh -p scripts/reinforcement_learning/sb3/train.py --task Isaac-Ant-v0 --headless

The first command works, while the second fails. The key difference is that the second script uses Hydra for argument parsing, while the first does not.

It seems that this line:

app_launcher = AppLauncher(args_cli)

injects --/app/livestream/allowResize=false argument into sys.argv. Adding this filtering after the line in which AppLauncher is created solves the issue:

...
app_launcher = AppLauncher(args_cli)
simulation_app = app_launcher.app

# Filter out AppLauncher-injected args before Hydra sees them
sys.argv = [sys.argv[0]] + [arg for arg in hydra_args if not arg.startswith("--/")]
...

[Chengnotwang]

@tlaguz Thanks,it work for me !

[Viru97]

Hii @Chengnotwang,
How to close this WebRTC Streaming Client safely?
Right now when i close it i get
2025-08-04 14:54:52 [57,428ms] [Error] [carb.livestream-rtc.plugin] nvstPushStreamData timeout for eye 0, stream (nil).
and my training stops.

Thanks!
@tlaguz @RandomOakForest