VideosHelper Module

Convenience helpers for video I/O and frame access (OpenCV wrappers).

class HMB.VideosHelper.VideosHelper[source]

Bases: object

VideosHelper: Helpers for common video operations using OpenCV.

Methods provided:

  • ReadVideo(videoPath)

  • WriteVideo(videoPath, frames, fps, frameSize, fourccType=”mp4v”)

  • ShowVideo(video, frameIndex)

  • ShowVideoFrames(video, frameIndexRange)

  • GetVideoFrames(video)

  • GetVideoFramesCount(video)

  • GetVideoFPS(video)

  • GetVideoFrameSize(video)

  • GetVideoFrameSizeString(video)

  • GetVideoDuration(video)

  • GetVideoFrame(video, frameIndex)

  • GetVideoFrameTime(video, frameIndex)

  • GetVideoFrameIndex(video, frameTime)

  • GetVideoFrameIndexRange(video, frameTimeRange)

  • GetVideoFrameTimeRange(video, frameIndexRange)

  • GetVideoFrameRange(video, frameIndexRange)

ReadVideo(videoPath)[source]

Open a video file and return a cv2.VideoCapture object.

Parameters:

videoPath (str) – Path to the video file.

Returns:

Opened video capture object.

Return type:

cv2.VideoCapture

WriteVideo(videoPath, frames, fps, frameSize, fourccType='mp4v')[source]

Write a sequence of frames to a video file.

Parameters:

  • videoPath (str) – Output path for the video file.

  • frames (Iterable) – Sequence of frames (NumPy arrays) to write.

  • fps (float) – Frames per second.

  • frameSize (tuple) – (width, height) of the frames.

  • fourccType (str) – FourCC codec string (default “mp4v”).

ShowVideo(video, frameIndex)[source]

Display a single frame from a video using OpenCV GUI (blocking until a key press).

Parameters:

  • video (cv2.VideoCapture) – Video capture object.

  • frameIndex (int) – Index of the frame to display.

ShowVideoFrames(video, frameIndexRange)[source]

Display multiple frames by index range.

Parameters:

  • video (cv2.VideoCapture) – Video capture object.

  • frameIndexRange (Iterable) – Iterable of frame indices to display.

GetVideoFrames(video)[source]

Read all frames from an opened cv2.VideoCapture into a list.

Parameters:

video (cv2.VideoCapture) – Opened video capture object.

Returns:

List of frames as NumPy arrays.

Return type:

list

GetVideoFramesCount(video)[source]

Get the total frame count of a video.

Parameters:

video (cv2.VideoCapture) – Opened video capture object.

Returns:

Total number of frames (may be 0 for some live streams).

Return type:

int

GetVideoFPS(video)[source]

Return the frames-per-second (FPS) rate for the video.

Parameters:

video (cv2.VideoCapture) – Opened video capture object.

Returns:

FPS value.

Return type:

float

GetVideoFrameSize(video)[source]

Get the video frame size as (width, height).

Parameters:

video (cv2.VideoCapture) – Opened video capture object.

Returns:

(width, height) in pixels.

Return type:

tuple

GetVideoFrameSizeString(video)[source]

Return a human-readable frame size string like “640x480”.

Parameters:

video (cv2.VideoCapture) – Opened video capture object.

Returns:

Frame size string.

Return type:

str

GetVideoDuration(video)[source]

Estimate video duration in seconds using frame count and fps.

Parameters:

video (cv2.VideoCapture) – Opened video capture object.

Returns:

Duration in seconds.

Return type:

float

GetVideoFrame(video, frameIndex)[source]

Retrieve a specific frame by index from an opened video.

Parameters:

  • video (cv2.VideoCapture) – Opened video capture object.

  • frameIndex (int) – Frame index.

Returns:

Frame image array (BGR color by OpenCV convention).

Return type:

numpy.ndarray

GetVideoFrameTime(video, frameIndex)[source]

Convert a frame index to its timestamp (in seconds) using FPS.

Parameters:

  • video (cv2.VideoCapture) – Opened video capture object.

  • frameIndex (int) – Frame index.

Returns:

Timestamp in seconds.

Return type:

float

GetVideoFrameIndex(video, frameTime)[source]

Convert a timestamp (seconds) to a fractional frame index.

Parameters:

  • video (cv2.VideoCapture) – Opened video capture object.

  • frameTime (float) – Timestamp in seconds.

Returns:

Frame index (may be fractional).

Return type:

float

GetVideoFrameIndexRange(video, frameTimeRange)[source]

Convert a list/iterable of timestamps to frame indices.

Parameters:

  • video (cv2.VideoCapture) – Opened video capture object.

  • frameTimeRange (Iterable) – Iterable of timestamps in seconds.

Returns:

List of frame indices (may be fractional).

Return type:

list

GetVideoFrameTimeRange(video, frameIndexRange)[source]

Convert a list/iterable of frame indices to timestamps.

Parameters:

  • video (cv2.VideoCapture) – Opened video capture object.

  • frameIndexRange (Iterable) – Iterable of frame indices.

Returns:

List of timestamps in seconds.

Return type:

list

GetVideoFrameRange(video, frameIndexRange)[source]

Retrieve multiple frames by their indices and return them as a list.

Parameters:

  • video (cv2.VideoCapture) – Opened video capture object.

  • frameIndexRange (Iterable) – Iterable of frame indices.

Returns:

List of frames as NumPy arrays.

Return type:

list