avi-r 1.0

A robust reader for avi videos.

AVI-R Package

Version 1.0

Author: Lijun Yu

Email: [e-mail]

A robust reader for AVI video files. Originally designed for the MEVA dataset.

Installation

pip install avi-r

Usage

A robust video loader that deals with missing frames in the MEVA dataset.

This video loader is developed based on PyAV package. The pims package was also a good reference despite its compatibility issue with current PyAV.

For the videos in the MEVA, using cv2.VideoCapture would result in wrong frame ids as it never counts the missing frames. If you are using MEVA, I suggest you change to this video loader ASAP.

Replace cv2.VideoCapture

According to my test, this video loader returns the exact same frame as cv2.VideoCapture unless missing frame or decoding error occured. To replace the cv2.VideoCapture objects in legacy codes, simply change from

import cv2
cap = cv2.VideoCapture(video_path)

to

from diva_io.video import VideoReader
cap = VideoReader(video_path)

VideoReader.read follows the schema of cv2.VideoCapture.read but automatically inserts the missing frames while reading the video.

Iterator Interface

video = VideoReader(video_path)
for frame in video:
    # frame is a diva_io.video.frame.Frame object
    image = frame.numpy()
    # image is an uint8 array in a shape of (height, width, channel[BGR])
    # ... Do something with the image

Random Access

Random access of a frame requires decoding from the nearest key frame (approximately every 60 frames for MEVA). Averagely, this introduces a constant overhead of 0.1 seconds, which is much faster than iterating from the beginning.

start_frame_id = 1500
length = 100
video.seek(start_frame_id)
for frame in video.get_iter(length):
    image = frame.numpy()
    # ... Do something with the image

Video Properties

video.width # cap.get(cv2.CAP_PROP_FRAME_WIDTH)
video.height # cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
video.fps # cap.get(cv2.CAP_PROP_FPS)
video.length # cap.get(cv2.CAP_PROP_FRAME_COUNT)

Other Interfaces

For other usages, please see the comments in video/reader.py.

Speed

See speed.md.