video_utils.py

import shutil
from typing import Optional, Tuple

import cv2


def change_video_resolution_and_fps(video_path: str, output_path: str,
                                    new_resolution: Optional[Tuple[int, int]] = None,
                                    new_fps: Optional[int] = None,
                                    acceptable_fps_violation: int = 0) -> bool:
    cap = cv2.VideoCapture(video_path)

    try:
        original_width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
        original_height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
        resolution = (original_width, original_height)
        fps = int(cap.get(cv2.CAP_PROP_FPS))
        # Specify the new_resolution and new_fps for the cut video
        new_resolution = new_resolution if new_resolution else resolution
        new_fps = fps if ((not new_fps) or (abs(new_fps - fps) <= acceptable_fps_violation)) else new_fps
        fps_decrease_factor = fps / new_fps
        if not fps_decrease_factor.is_integer():
            raise ValueError(f"New fps ({new_fps}) must be a divisor of the current fps ({fps})")

        if fps == new_fps and (original_width, original_height) == new_resolution:
            shutil.copy(video_path, output_path)
            return True

        current_frame = 0

        # Read first frame
        ret, frame = cap.read()
        if not ret:
            # Video has ended, without us recording anything
            return False

        # Initialize the video writer to save the cut video
        fourcc = cv2.VideoWriter_fourcc(*'XVID')
        out = cv2.VideoWriter(output_path, fourcc, new_fps, new_resolution, isColor=True)
        new_video_current_frame = 0

        while ret:
            if current_frame % fps_decrease_factor == 0:
                if resolution != new_resolution:
                    # Resize the frame to the desired new_resolution before writing it
                    frame = cv2.resize(frame, new_resolution, interpolation=cv2.INTER_AREA)
                # Write the frame to the cut video
                out.write(frame)
                new_video_current_frame += 1

            current_frame += 1
            # Read next frame
            ret, frame = cap.read()

        # We're done recording
        out.release()
        return new_video_current_frame > 0

    finally:
        # Release the video capture and close all windows
        cap.release()