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Real4D data format

Paths

The first path component identifies the source subset (dynerf for N3DV or meetroom), followed by a scene. Within each scene, modalities are grouped so that large subsets can be downloaded independently.

For trajectory cam00_01 and zero-based frame index i, use file number i + 1:

images/cam00_01/cam00_01_000001.jpg
depths/cam00_01/cam00_01_000001.jpg.geometric.png
depth_vis/cam00_01/cam00_01_000001.jpg
camera_params/cam00_01.json  # entry 0

RGB

RGB frames are 8-bit three-channel JPEG files. N3DV-derived frames have size 1352 x 1014; MeetRoom-derived frames have size 1280 x 720.

Depth

Depth files are single-channel 16-bit PNG images. A stored value d represents d / 1000 meters. Value zero is the invalid mask and indicates negligible accumulated opacity. These values are rendered pseudo-labels derived from the reconstructed dynamic scene, not measurements from a depth sensor.

from PIL import Image
import numpy as np

depth_mm = np.asarray(Image.open(depth_path), dtype=np.uint16)
valid = depth_mm > 0
depth_m = depth_mm.astype(np.float32) / 1000.0

depth_vis is only a colorized preview and must not be used as numeric depth.

Camera manifest

Each <trajectory>.json is a list of 300 dictionaries in temporal order. The main fields are:

Field Meaning
timestamp Scene time in seconds.
w2c 4 x 4 world-to-camera homogeneous transform.
R 3 x 3 rotation component used by the renderer.
T 3-vector translation component used by the renderer.
fl_x, fl_y Focal lengths in pixels.
cx, cy Principal point in pixels.
FoVx, FoVy Horizontal and vertical field of view in radians.
width, height Image dimensions in pixels.
image_name Source reference-camera identifier; not an output filename.

The camera matrix is analytically prescribed along the interpolation path. It is exact with respect to that virtual trajectory; it is not an SfM/SLAM estimate. Load the JSON record at list index i together with file number i + 1.

Trajectories

cam{a}_{b} denotes the ordered interpolation from reference camera a to reference camera b. Because the pair is ordered, cam00_01 and cam01_00 are distinct. cam00_00 is a static-viewpoint temporal sequence. Every trajectory contains 300 frames spanning the scene's 10-second temporal extent.

Preview videos

video/<trajectory>_rgb.mp4 and video/<trajectory>_depth.mp4 are provided for quick browsing at 30 fps. They are convenience derivatives; image sequences and camera JSON are the authoritative data.