degirum-video-capture 0.1.1

High-performance video capture library using FFmpeg

degirum_video_capture - DeGirum video reading and decoding library

This package is intended to replace OpenCV's cv2.VideoCapture() class for the purposes of video reading and decoding in performance-based pipelines. The goals of this project are to:

1. Provide more frames per second than cv2.VideoCapture.read()
2. Provide utility by allowing the user to enable select filters when reading a video
3. Remaining compatible with in-process opencv-python by avoiding ffmpeg libaray symbol conflict

License

MIT License

External Licenses

Installation

pip install degirum-video-capture

Documentation

Class VideoCapture

Note: VideoCapture can be used as a context manager

def __init__( [source], [filter args] )

ARGS

• optional (string) source: source to read from. Acceptable values: filepath, rtsp stream, usb camera
• optional filter args:
  • (int) width: Width to which the output frame will be resized and padded to. Aspect ratio will be maintained.
  • (int) height: Height to which the output frame will be resized and padded to. Aspect ratio will be maintained.

RETURNS

• VideoCapture object

def open( source, [filter args] )

ARGS

• (string) source: same as source in __init__
• optional filter args: same as filter args in __init__

Note: open() does not need to be explicitly called if source was provided in __init__.

RETURNS

• True if source opened successfully. False otherwise.

def read()

RETURNS

• tuple: (success: bool, frame: np.ndarray or None)
  • success: True if a frame was read, False otherwise.
  • frame: numpy array (height, width, 3) in BGR format or None

def isOpened()

RETURNS

• True if source is opened, False otherwise.

def close()

Closes source

def get( prop_id )

ARGS

• (int) prop_id: Property identifier (use CAP_PROP_* constants)

RETURNS

• float: Property value, or -1 if not supported/available

CAP_PROP_*:

0 = CAP_PROP_POS_MSEC
1 = CAP_PROP_POS_FRAMES
2 = CAP_PROP_POS_AVI_RATIO
3 = CAP_PROP_FRAME_WIDTH
4 = CAP_PROP_FRAME_HEIGHT
5 = CAP_PROP_FPS
6 = CAP_PROP_FOURCC
7 = CAP_PROP_FRAME_COUNT

Example Usage

No resizing, explicit open + checks

import degirum_video_capture as dvc

cap = dvc.VideoCapture()
cap.open("example.mp4")

if cap.isOpened():
    while True:
        ret, frame = capture.read()
        if not ret:
            break
        # Do something with the frame
        foo_bar(frame)

    cap.close()

Resizing + letterboxing, implicit open and no checks, used as context manager

import degirum_video_capture as dvc

with dvc.VideoCapture("example.mp4", 640, 640) as capture:
    while True:
        ret, frame = capture.read()
        if not ret:
            break
        # Do something with the frame
        foo_bar(frame)