meta_file_processing.py

import numpy as np

# Initialize dictionaries and counters for tracking frame differences and lost frames
frame_diff_counts = {}
previous_frame_number = None
previous_frame_line = None
total_frames = 0
frames_lost = 0
first_timestamp = None
last_timestamp = None

# Open and read the metadata file generated by the frame capture script
with open("frames_meta_20240101_010101.txt", "r") as meta_file:
    for line in meta_file:
        # Extract frame number and timestamp from the line
        frame_number, timestamp, _, _ = map(float, line.strip().split())

        # Record the first and last timestamps for FPS calculation
        if first_timestamp is None:
            first_timestamp = timestamp
        last_timestamp = timestamp

        # Increment the total frame count
        total_frames += 1

        # Calculate the difference between consecutive frame numbers
        if previous_frame_number is not None:
            frame_diff = int(frame_number - previous_frame_number)
            frame_diff_counts[frame_diff] = frame_diff_counts.get(frame_diff, 0) + 1

            # If frames were lost (gap in frame numbers), increment the lost frames counter
            if frame_diff > 1:
                frames_lost += frame_diff - 1
                print("Fields in the following lines represent: Frame Number, Timestamp, Delta First, Delta Previous")
                print(previous_frame_line.strip())
                print(line.strip())
                print()

        # Update the previous frame variables for the next iteration
        previous_frame_number = frame_number
        previous_frame_line = line

# Display a summary of frame differences and their frequencies
print("Difference between frame numbers | Percentage of instances")
print("----------------------------------+-----------------------")
total_frame_diffs = sum(frame_diff_counts.values())
for frame_diff, count in sorted(frame_diff_counts.items()):
    percentage = (count / total_frame_diffs) * 100
    print(f"{frame_diff:<32}| {percentage:<22}")

# Calculate the effective FPS based on the time span between the first and last frames
effective_fps = total_frames / ((last_timestamp - first_timestamp) / 1000)
print(f"\nEffective FPS: {effective_fps}")
print(f"\nTotal number of frames collected: {total_frames}")
print(f"\nNumber of frames lost: {frames_lost}")