normalise_reference_locations.py

# Part 1: Load file and visualize/transform single reference locations
# Requires https://pypi.org/project/msgpack/

import sys
import msgpack

# Adjust the following variables to your recording
world_video_resolution = (1280, 720)
path_to_reference_locations = "/Volumes/32TB/users/ppr/recordings/2019_09_04/000/offline_data/reference_locations.msgpack"

with open(path_to_reference_locations, "rb") as fh:
    reference_locations = msgpack.unpack(fh, raw=False)

assert reference_locations["version"] == 1, "Unknown reference locations format"

data = reference_locations["data"]

if not data:
    print("Warning: No reference data found! Aborting.")
    sys.exit(1)

# Each reference location consists of:
# Location in pixels `[x, y]`
# Frame index `idx`
# Frame timestamp `ts`
[[x, y], idx, ts] = data[0]  # first element
print(f"First reference location:\n\tx={x}\n\ty={y}\n\tidx={idx}\n\tts={ts}")

x_norm = x / world_video_resolution[0]
y_norm = y / world_video_resolution[1]
print(f"Normalized reference location:\n\tx={x_norm}\n\ty={y_norm}")

# Part 2: Load and transform all reference locations with pandas
# Requires: https://pypi.org/project/pandas/

# In order to load the data with pandas, we need to flatten the data:
# The new data format will be `[x, y, idx, ts]` instead of `[[x, y], idx, ts]`
data = [[*pos, idx, ts] for (pos, idx, ts) in data]

import pandas as pd

data_frame = pd.DataFrame(
    data, columns=["pixels_x", "pixels_y", "frame_idx", "frame_ts"]
)

data_frame["norm_x"] = data_frame["pixels_x"] / world_video_resolution[0]
data_frame["norm_y"] = data_frame["pixels_y"] / world_video_resolution[1]

print("Loaded and transformed reference locations:")
print(data_frame.head())

# Part 3: Saving result as csv

# Use pathlib for simple path manipulations:
# https://docs.python.org/3/library/pathlib.html#module-pathlib
import pathlib

path_to_reference_locations = pathlib.Path(path_to_reference_locations)
path_to_reference_locations_csv = path_to_reference_locations.with_suffix(".csv")

print(f"Writing result to {path_to_reference_locations_csv}")
data_frame.to_csv(path_to_reference_locations_csv, index=False)