aedat

AEDAT is a fast AEDAT 4 python reader, with a Rust underlying implementation.

Run pip install aedat to install it.

• Example
• Process frames
  • Pillow (PIL)
  • OpenCV
• Detailed example
• Install from source
  • Linux
  • macOS
  • Windows
• Contribute
• Publish

Example

The aedat library provides a single class: Decoder. A decoder object is created by passing a file name to Decoder. The file name must be a path-like object.

import aedat

decoder = aedat.Decoder("/path/to/file.aedat")
print(decoder.id_to_stream())

for packet in decoder:
    print(packet["stream_id"], end=": ")
    if "events" in packet:
        print("{} polarity events".format(len(packet["events"])))
    elif "frame" in packet:
        print("{} x {} frame".format(packet["frame"]["width"], packet["frame"]["height"]))
    elif "imus" in packet:
        print("{} IMU samples".format(len(packet["imus"])))
    elif "triggers" in packet:
        print("{} trigger events".format(len(packet["triggers"])))

Process frames

Pillow (PIL)

import aedat
import PIL.Image # https://pypi.org/project/Pillow/

index = 0
for packet in decoder:
    if "frame" in packet:
        image = PIL.Image.fromarray(
            packet["frame"]["pixels"],
            mode=packet["frame"]["format"],
        )
        image.save(f"{index}.png")
        index += 1

The four format values are Pillow mode strings, so they can be passed to PIL.Image.fromarray directly.

OpenCV

import aedat
import cv2 # https://pypi.org/project/opencv-python/

index = 0
for packet in decoder:
    if "frame" in packet:
        image = packet["frame"]["pixels"]
        if packet["frame"]["format"] == "RGB":
            image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)
        elif packet["frame"]["format"] == "RGBA":
            image = cv2.cvtColor(image, cv2.COLOR_RGBA2BGRA)
        cv2.imwrite(f"{index}.png", image)
        index += 1

Only the color formats need a channel swap. cv2.imwrite writes "L" and "I;16" arrays as-is.

Detailed example

This is the same as the first example, with detailed comments:

import aedat

decoder = aedat.Decoder("/path/to/file.aedat")
"""
decoder is a packet iterator with an additional method id_to_stream
id_to_stream returns a dictionary with the following structure:
{
    <int>: {
        "type": <str>,
    }
}
type is one of "events", "frame", "imus", "triggers"
if type is "events" or "frame", its parent dictionary has the following structure:
{
    "type": <str>,
    "width": <int>,
    "height": <int>,
}
"""
print(decoder.id_to_stream())

for packet in decoder:
    """
    packet is a dictionary with the following structure:
    {
        "stream_id": <int>,
    }
    packet also has exactly one of the following fields:
        "events", "frame", "imus", "triggers"
    """
    print(packet["stream_id"], end=": ")
    if "events" in packet:
        """
        packet["events"] is a structured numpy array with the following dtype:
            [
                ("t", "<u8"),
                ("x", "<u2"),
                ("y", "<u2"),
                (("p", "on"), "?"),
            ]
        """
        print("{} polarity events".format(len(packet["events"])))
    elif "frame" in packet:
        """
        packet["frame"] is a dictionary with the following structure:
            {
                "t": <int>,
                "begin_t": <int>,
                "end_t": <int>,
                "exposure_begin_t": <int>,
                "exposure_end_t": <int>,
                "format": <str>,
                "width": <int>,
                "height": <int>,
                "offset_x": <int>,
                "offset_y": <int>,
                "pixels": <numpy.ndarray>,
            }
        format is one of "L", "I;16", "RGB", "RGBA":
            "L"     OPENCV_8U_C1,  pixels shape (H, W), dtype uint8
            "I;16"  OPENCV_16U_C1, pixels shape (H, W), dtype uint16
            "RGB"   OPENCV_8U_C3 or OPENCV_16U_C3, shape (H, W, 3), dtype uint8 or uint16
            "RGBA"  OPENCV_8U_C4 or OPENCV_16U_C4, shape (H, W, 4), dtype uint8 or uint16
        File pixels are OpenCV BGR(A). The decoder swaps to RGB(A) to match Pillow.
        DAVIS recordings from jAER store APS frames as OPENCV_16U_C1 ("I;16").
        Unknown OpenCV type codes are skipped (a UserWarning is issued once) so events and IMU stay readable.
        """
        print("{} x {} frame".format(packet["frame"]["width"], packet["frame"]["height"]))
    elif "imus" in packet:
        """
        packet["imus"] is a structured numpy array with the following dtype:
            [
                ("t", "<u8"),
                ("temperature", "<f4"),
                ("accelerometer_x", "<f4"),
                ("accelerometer_y", "<f4"),
                ("accelerometer_z", "<f4"),
                ("gyroscope_x", "<f4"),
                ("gyroscope_y", "<f4"),
                ("gyroscope_z", "<f4"),
                ("magnetometer_x", "<f4"),
                ("magnetometer_y", "<f4"),
                ("magnetometer_z", "<f4"),
            ]
        """
        print("{} IMU samples".format(len(packet["imus"])))
    elif "triggers" in packet:
        """
        packet["triggers"] is a structured numpy array with the following dtype:
            [
                ("t", "<u8"),
                ("source", "u1"),
            ]
        the source value has the following meaning:
            0: timestamp reset
            1: external signal rising edge
            2: external signal falling edge
            3: external signal pulse
            4: external generator rising edge
            5: external generator falling edge
            6: frame begin
            7: frame end
            8: exposure begin
            9: exposure end
        """
        print("{} trigger events".format(len(packet["triggers"])))

Because the lifetime of the file handle is managed by Rust, decoder objects are not compatible with the with statement. To ensure garbage collection, point the decoder variable to something else, for example None, when you are done using it:

import aedat

decoder = aedat.Decoder("/path/to/file.aedat")
# do something with decoder
decoder = None

Install from source

Local build (first run).

python3 -m venv .venv
source .venv/bin/activate
pip install --upgrade pip
pip install maturin numpy
maturin develop  # or maturin develop --release to build with optimizations

Local build (subsequent runs).

source .venv/bin/activate
maturin develop  # or maturin develop --release to build with optimizations

After changing any of the files in flatbuffers, one must run:

flatc --rust -o src/ flatbuffers/*.fbs

To run the tests, run:

pip install --group dev
python -m pytest tests/

To format and check the code, run:

cargo fmt
ruff format
ruff check
ty check

Publish

1. Bump the version number in Cargo.toml and pyproject.toml.

2. Create a new release on GitHub.