Method open

tools/render/render_episode.py:1328–1371

(
        cls,
        paths: Mapping[str, Path],
        *,
        fps: float,
        quality: int,
    )

    @classmethod
    def open(
        cls,
        paths: Mapping[str, Path],
        *,
        fps: float,
        quality: int,
    ) -> "_VideoWriterSet":
        if not paths:
            return cls({})
        backend = _preferred_video_backend()
        if backend is None:
            raise RuntimeError(
                "MP4 writing requires either imageio with an ffmpeg/pyav backend "
                "or OpenCV. Install one of those or pass --no-video."
            )
        if backend == "opencv":
            return cls(
                {
                    camera_id: _OpenCvVideoWriter(path, fps=float(fps))
                    for camera_id, path in paths.items()
                }
            )

        import imageio.v2 as imageio

        writers: dict[str, Any] = {}
        try:
            for camera_id, path in paths.items():
                path.parent.mkdir(parents=True, exist_ok=True)
                if path.exists():
                    path.unlink()
                writers[camera_id] = imageio.get_writer(
                    str(path),
                    fps=float(fps),
                    codec="libx264",
                    quality=int(quality),
                    macro_block_size=1,
                    ffmpeg_params=["-pix_fmt", "yuv420p"],
                )
        except BaseException:
            for writer in writers.values():
                writer.close()
            raise
        return cls(writers)

    def append(self, camera_id: str, rgb: Any) -> None:
        writer = self._writers.get(camera_id)