import os
from typing import Callable
from gymnasium.wrappers.monitoring import video_recorder
from stable_baselines3.common.vec_env.base_vec_env import VecEnv, VecEnvObs, VecEnvStepReturn, VecEnvWrapper
from stable_baselines3.common.vec_env.dummy_vec_env import DummyVecEnv
from stable_baselines3.common.vec_env.subproc_vec_env import SubprocVecEnv
[docs]class VecVideoRecorder(VecEnvWrapper):
"""
Wraps a VecEnv or VecEnvWrapper object to record rendered image as mp4 video.
It requires ffmpeg or avconv to be installed on the machine.
:param venv:
:param video_folder: Where to save videos
:param record_video_trigger: Function that defines when to start recording.
The function takes the current number of step,
and returns whether we should start recording or not.
:param video_length: Length of recorded videos
:param name_prefix: Prefix to the video name
"""
video_recorder: video_recorder.VideoRecorder
def __init__(
self,
venv: VecEnv,
video_folder: str,
record_video_trigger: Callable[[int], bool],
video_length: int = 200,
name_prefix: str = "rl-video",
):
VecEnvWrapper.__init__(self, venv)
self.env = venv
# Temp variable to retrieve metadata
temp_env = venv
# Unwrap to retrieve metadata dict
# that will be used by gym recorder
while isinstance(temp_env, VecEnvWrapper):
temp_env = temp_env.venv
if isinstance(temp_env, DummyVecEnv) or isinstance(temp_env, SubprocVecEnv):
metadata = temp_env.get_attr("metadata")[0]
else:
metadata = temp_env.metadata
self.env.metadata = metadata
assert self.env.render_mode == "rgb_array", f"The render_mode must be 'rgb_array', not {self.env.render_mode}"
self.record_video_trigger = record_video_trigger
self.video_folder = os.path.abspath(video_folder)
# Create output folder if needed
os.makedirs(self.video_folder, exist_ok=True)
self.name_prefix = name_prefix
self.step_id = 0
self.video_length = video_length
self.recording = False
self.recorded_frames = 0
[docs] def reset(self) -> VecEnvObs:
obs = self.venv.reset()
self.start_video_recorder()
return obs
def start_video_recorder(self) -> None:
self.close_video_recorder()
video_name = f"{self.name_prefix}-step-{self.step_id}-to-step-{self.step_id + self.video_length}"
base_path = os.path.join(self.video_folder, video_name)
self.video_recorder = video_recorder.VideoRecorder(
env=self.env, base_path=base_path, metadata={"step_id": self.step_id}
)
self.video_recorder.capture_frame()
self.recorded_frames = 1
self.recording = True
def _video_enabled(self) -> bool:
return self.record_video_trigger(self.step_id)
[docs] def step_wait(self) -> VecEnvStepReturn:
obs, rews, dones, infos = self.venv.step_wait()
self.step_id += 1
if self.recording:
self.video_recorder.capture_frame()
self.recorded_frames += 1
if self.recorded_frames > self.video_length:
print(f"Saving video to {self.video_recorder.path}")
self.close_video_recorder()
elif self._video_enabled():
self.start_video_recorder()
return obs, rews, dones, infos
def close_video_recorder(self) -> None:
if self.recording:
self.video_recorder.close()
self.recording = False
self.recorded_frames = 1
[docs] def close(self) -> None:
VecEnvWrapper.close(self)
self.close_video_recorder()
def __del__(self):
self.close_video_recorder()