Utils

Auto-generated documentation for musicalgestures._utils module.

• Mgt-python / Modules / Musicalgestures / Utils
  • FFmpegError
  • FFprobeError
  • MgFigure
    • MgFigure().show
  • MgImage
  • MgProgressbar
    • MgProgressbar().adjust_printlength
    • MgProgressbar().get_now
    • MgProgressbar().over_time_limit
    • MgProgressbar().progress
  • NoDurationError
  • NoStreamError
  • WrongContainer
  • audio_dilate
  • cast_into_avi
  • clamp
  • convert
  • convert_to_avi
  • convert_to_grayscale
  • convert_to_mp4
  • convert_to_webm
  • crop_ffmpeg
  • embed_audio_in_video
  • extract_subclip
  • extract_wav
  • ffmpeg_cmd
  • ffprobe
  • frame2ms
  • framediff_ffmpeg
  • generate_outfilename
  • get_box_video_ratio
  • get_first_frame_as_image
  • get_fps
  • get_frame_planecount
  • get_framecount
  • get_length
  • get_widthheight
  • has_audio
  • in_colab
  • motiongrams_ffmpeg
  • motionvideo_ffmpeg
  • pass_if_container_is
  • pass_if_containers_match
  • quality_metrics
  • rotate_video
  • roundup
  • scale_array
  • scale_num
  • str2sec
  • threshold_ffmpeg
  • unwrap_str
  • wrap_str

FFmpegError

[find in source code]

class FFmpegError(Exception):
    def __init__(message):

FFprobeError

[find in source code]

class FFprobeError(Exception):
    def __init__(message):

MgFigure

[find in source code]

class MgFigure():
    def __init__(
        figure=None,
        figure_type=None,
        data=None,
        layers=None,
        image=None,
    ):

Class for working with figures and plots within the Musical Gestures Toolbox.

MgFigure().show

[find in source code]

def show():

Shows the internal matplotlib.pyplot.figure.

MgImage

[find in source code]

class MgImage():
    def __init__(filename):

Class for handling images in the Musical Gestures Toolbox.

MgProgressbar

[find in source code]

class MgProgressbar():
    def __init__(
        total=100,
        time_limit=0.5,
        prefix='Progress',
        suffix='Complete',
        decimals=1,
        length=40,
        fill='█',
    ):

Calls in a loop to create terminal progress bar.

MgProgressbar().adjust_printlength

[find in source code]

def adjust_printlength():

MgProgressbar().get_now

[find in source code]

def get_now():

Gets the current time.

Returns

• datetime.datetime.timestamp - The current time.

MgProgressbar().over_time_limit

[find in source code]

def over_time_limit():

Checks if we should redraw the progress bar at this moment.

Returns

• bool - True if equal or more time has passed than self.time_limit since the last redraw.

MgProgressbar().progress

[find in source code]

def progress(iteration):

Progresses the progress bar to the next step.

Arguments

• iteration float - The current iteration. For example, the 57th out of 100 steps, or 12.3s out of the total 60s.

NoDurationError

[find in source code]

class NoDurationError(FFprobeError):

See also

• FFprobeError

NoStreamError

[find in source code]

class NoStreamError(FFprobeError):

See also

• FFprobeError

WrongContainer

[find in source code]

class WrongContainer(Exception):
    def __init__(message):

audio_dilate

[find in source code]

def audio_dilate(
    filename,
    dilation_ratio=1,
    target_name=None,
    overwrite=False,
):

Time-stretches or -shrinks (dilates) an audio file using ffmpeg.

Arguments

• filename str - Path to the audio file to dilate.
• dilation_ratio float, optional - The source file's length divided by the resulting file's length. Defaults to 1.
• target_name str, optional - The name of the output video. Defaults to None (which assumes that the input filename with the suffix "_dilated" should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the output audio file.

cast_into_avi

[find in source code]

def cast_into_avi(filename, target_name=None, overwrite=False):

Experimental Casts a video into and .avi container using ffmpeg. Much faster than convert_to_avi, but does not always work well with cv2 or built-in video players.

Arguments

• filename str - Path to the input video file.
• target_name str, optional - Target filename as path. Defaults to None (which assumes that the input filename should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the output '.avi' file.

clamp

[find in source code]

def clamp(num, min_value, max_value):

Clamps a number between a minimum and maximum value.

Arguments

• num float - The number to clamp.
• min_value float - The minimum allowed value.
• max_value float - The maximum allowed value.

Returns

• float - The clamped number.

convert

[find in source code]

def convert(filename, target_name, overwrite=False):

Converts a video to another format/container using ffmpeg.

Arguments

• filename str - Path to the input video file to convert.
• target_name str - Target filename as path.
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the output file.

convert_to_avi

[find in source code]

def convert_to_avi(filename, target_name=None, overwrite=False):

Converts a video to one with .avi extension using ffmpeg.

Arguments

• filename str - Path to the input video file to convert.
• target_name str, optional - Target filename as path. Defaults to None (which assumes that the input filename should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the output '.avi' file.

convert_to_grayscale

[find in source code]

def convert_to_grayscale(filename, target_name=None, overwrite=False):

Converts a video to grayscale using ffmpeg.

Arguments

• filename str - Path to the input video file.
• target_name str, optional - Target filename as path. Defaults to None (which assumes that the input filename with the suffix "_gray" should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the grayscale video file.

convert_to_mp4

[find in source code]

def convert_to_mp4(filename, target_name=None, overwrite=False):

Converts a video to one with .mp4 extension using ffmpeg.

Arguments

• filename str - Path to the input video file to convert.
• target_name str, optional - Target filename as path. Defaults to None (which assumes that the input filename should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the output '.mp4' file.

convert_to_webm

[find in source code]

def convert_to_webm(filename, target_name=None, overwrite=False):

Converts a video to one with .webm extension using ffmpeg.

Arguments

• filename str - Path to the input video file to convert.
• target_name str, optional - Target filename as path. Defaults to None (which assumes that the input filename should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the output '.webm' file.

crop_ffmpeg

[find in source code]

def crop_ffmpeg(filename, w, h, x, y, target_name=None, overwrite=False):

Crops a video using ffmpeg.

Arguments

• filename str - Path to the input video file.
• w int - The desired width.
• h int - The desired height.
• x int - The horizontal coordinate of the top left pixel of the cropping rectangle.
• y int - The vertical coordinate of the top left pixel of the cropping rectangle.
• target_name str, optional - The name of the output video. Defaults to None (which assumes that the input filename with the suffix "_crop" should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filenames to avoid overwriting. Defaults to False.

Returns

• str - Path to the output video.

embed_audio_in_video

[find in source code]

def embed_audio_in_video(source_audio, destination_video, dilation_ratio=1):

Embeds an audio file as the audio channel of a video file using ffmpeg.

Arguments

• source_audio str - Path to the audio file to embed.
• destination_video str - Path to the video file to embed the audio file in.
• dilation_ratio float, optional - The source file's length divided by the resulting file's length. Defaults to 1.

extract_subclip

[find in source code]

def extract_subclip(filename, t1, t2, target_name=None, overwrite=False):

Extracts a section of the video using ffmpeg.

Arguments

• filename str - Path to the input video file.
• t1 float - The start of the section to extract in seconds.
• t2 float - The end of the section to extract in seconds.
• target_name str, optional - The name for the output file. If None, the name will be \<input name>SUB\<start time in ms>_\<end time in ms>.\<file extension>. Defaults to None.
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - Path to the extracted section as a video.

extract_wav

[find in source code]

def extract_wav(filename, target_name=None, overwrite=False):

Extracts audio from video into a .wav file via ffmpeg.

Arguments

• filename str - Path to the video file from which the audio track shall be extracted.
• target_name str, optional - The name of the output video. Defaults to None (which assumes that the input filename should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the output audio file.

ffmpeg_cmd

[find in source code]

def ffmpeg_cmd(
    command,
    total_time,
    pb_prefix='Progress',
    print_cmd=False,
    stream=True,
    pipe=None,
):

Run an ffmpeg command in a subprocess and show progress using an MgProgressbar.

Arguments

• command list - The ffmpeg command to execute as a list. Eg. ['ffmpeg', '-y', '-i', 'myVid.mp4', 'myVid.mov']
• total_time float - The length of the output. Needed mainly for the progress bar.
• pb_prefix str, optional - The prefix for the progress bar. Defaults to 'Progress'.
• print_cmd bool, optional - Whether to print the full ffmpeg command to the console before executing it. Good for debugging. Defaults to False.
• stream bool, optional - Whether to have a continuous output stream or just (the last) one. Defaults to True (continuous stream).
• pipe str, optional - Whether to pipe video frames from FFmpeg to numpy array. Possible to read the video frame by frame with pipe='read', to load video in memory with pipe='load', or to write the frames of a numpy array to a video file with pipe='write'. Defaults to None.

Raises

• KeyboardInterrupt - If the user stops the process.
• FFmpegError - If the ffmpeg process was unsuccessful.

ffprobe

[find in source code]

def ffprobe(filename):

Returns info about video/audio file using FFprobe.

Arguments

• filename str - Path to the video file to measure.

Returns

• str - decoded FFprobe output (stdout) as one string.

frame2ms

[find in source code]

def frame2ms(frame, fps):

Converts frames to milliseconds.

Arguments

• frame int - The index of the frame to be converted to milliseconds.
• fps int - Frames per second.

Returns

• int - The rounded millisecond value of the input frame index.

framediff_ffmpeg

[find in source code]

def framediff_ffmpeg(filename, target_name=None, color=True, overwrite=False):

Renders a frame difference video from the input using ffmpeg.

Arguments

• filename str - Path to the input video file.
• target_name str, optional - The name of the output video. Defaults to None (which assumes that the input filename with the suffix "_framediff" should be used).
• color bool, optional - If False, the output will be grayscale. Defaults to True.
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - Path to the output video.

generate_outfilename

[find in source code]

def generate_outfilename(requested_name):

Returns a unique filepath to avoid overwriting existing files. Increments requested filename if necessary by appending an integer, like "_0" or "_1", etc to the file name.

Arguments

• requested_name str - Requested file name as path string.

Returns

• str - If file at requested_name is not present, then requested_name, else an incremented filename.

get_box_video_ratio

[find in source code]

def get_box_video_ratio(filename, box_width=800, box_height=600):

Gets the box-to-video ratio between an arbitrarily defind box and the video dimensions. Useful to fit windows into a certain area.

Arguments

• filename str - Path to the input video file.
• box_width int, optional - The width of the box to fit the video into.
• box_height int, optional - The height of the box to fit the video into.

Returns

• int - The smallest ratio (ie. the one to use for scaling the video window to fit into the box).

get_first_frame_as_image

[find in source code]

def get_first_frame_as_image(
    filename,
    target_name=None,
    pict_format='.png',
    overwrite=False,
):

Extracts the first frame of a video and saves it as an image using ffmpeg.

Arguments

• filename str - Path to the input video file.
• target_name str, optional - The name for the output image. Defaults to None (which assumes that the input filename should be used).
• pict_format str, optional - The format to use for the output image. Defaults to '.png'.
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - Path to the output image file.

get_fps

[find in source code]

def get_fps(filename):

Gets the FPS (frames per second) value of a video using FFprobe.

Arguments

• filename str - Path to the video file to measure.

Returns

• float - The FPS value of the input video file.

get_frame_planecount

[find in source code]

def get_frame_planecount(frame):

Gets the planecount (color channel count) of a video frame.

Arguments

frame (numpy array): A frame extracted by cv2.VideoCapture().read().

Returns

• int - The planecount of the input frame, 3 or 1.

get_framecount

[find in source code]

def get_framecount(filename, fast=True):

Returns the number of frames in a video using FFprobe.

Arguments

• filename str - Path to the video file to measure.

Returns

• int - The number of frames in the input video file.

get_length

[find in source code]

def get_length(filename):

Gets the length (in seconds) of a video using FFprobe.

Arguments

• filename str - Path to the video file to measure.

Returns

• float - The length of the input video file in seconds.

get_widthheight

[find in source code]

def get_widthheight(filename):

Gets the width and height of a video using FFprobe.

Arguments

• filename str - Path to the video file to measure.

Returns

• int - The width of the input video file.
• int - The height of the input video file.

has_audio

[find in source code]

def has_audio(filename):

Checks if video has audio track using FFprobe.

Arguments

• filename str - Path to the video file to check.

Returns

• bool - True if filename has an audio track, False otherwise.

in_colab

[find in source code]

def in_colab():

Check's if the environment is a Google Colab document.

Returns

• bool - True if the environment is a Colab document, otherwise False.

motiongrams_ffmpeg

[find in source code]

def motiongrams_ffmpeg(
    filename,
    color=True,
    filtertype='regular',
    threshold=0.05,
    blur='none',
    use_median=False,
    kernel_size=5,
    invert=False,
    target_name_x=None,
    target_name_y=None,
    overwrite=False,
):

Renders horizontal and vertical motiongrams using ffmpeg.

Arguments

• filename str - Path to the input video file.
• color bool, optional - If False the input is converted to grayscale at the start of the process. This can significantly reduce render time. Defaults to True.
• filtertype str, optional - 'Regular' turns all values below thresh to 0. 'Binary' turns all values below thresh to 0, above thresh to 1. 'Blob' removes individual pixels with erosion method. Defaults to 'Regular'.
• thresh float, optional - Eliminates pixel values less than given threshold. Ranges from 0 to 1. Defaults to 0.05.
• blur str, optional - 'Average' to apply a 10px * 10px blurring filter, 'None' otherwise. Defaults to 'None'.
• use_median bool, optional - If True the algorithm applies a median filter on the thresholded frame-difference stream. Defaults to False.
• kernel_size int, optional - Size of the median filter (if use_median=True) or the erosion filter (if filtertype='blob'). Defaults to 5.
• invert bool, optional - If True, inverts colors of the motiongrams. Defaults to False.
• target_name_x str, optional - Target output name for the motiongram on the X axis. Defaults to None (which assumes that the input filename with the suffix "_mgx_ffmpeg" should be used).
• target_name_y str, optional - Target output name for the motiongram on the Y axis. Defaults to None (which assumes that the input filename with the suffix "_mgy_ffmpeg" should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filenames to avoid overwriting. Defaults to False.

Returns

• str - Path to the output horizontal motiongram (_mgx).
• str - Path to the output vertical motiongram (_mgy).

motionvideo_ffmpeg

[find in source code]

def motionvideo_ffmpeg(
    filename,
    color=True,
    filtertype='regular',
    threshold=0.05,
    blur='none',
    use_median=False,
    kernel_size=5,
    invert=False,
    target_name=None,
    overwrite=False,
):

Renders a motion video using ffmpeg.

Arguments

• filename str - Path to the input video file.
• color bool, optional - If False the input is converted to grayscale at the start of the process. This can significantly reduce render time. Defaults to True.
• filtertype str, optional - 'Regular' turns all values below thresh to 0. 'Binary' turns all values below thresh to 0, above thresh to 1. 'Blob' removes individual pixels with erosion method. Defaults to 'Regular'.
• thresh float, optional - Eliminates pixel values less than given threshold. Ranges from 0 to 1. Defaults to 0.05.
• blur str, optional - 'Average' to apply a 10px * 10px blurring filter, 'None' otherwise. Defaults to 'None'.
• use_median bool, optional - If True the algorithm applies a median filter on the thresholded frame-difference stream. Defaults to False.
• kernel_size int, optional - Size of the median filter (if use_median=True) or the erosion filter (if filtertype='blob'). Defaults to 5.
• invert bool, optional - If True, inverts colors of the motion video. Defaults to False.
• target_name str, optional - Defaults to None (which assumes that the input filename with the suffix "_motion" should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - Path to the output video.

pass_if_container_is

[find in source code]

def pass_if_container_is(container, file):

Checks if a file's extension matches a desired one. Passes if so, raises WrongContainer if not.

Arguments

• container str - The container to match.
• file str - Path to the file to inspect.

Raises

• WrongContainer - If the file extension (container) matches the desired one.

pass_if_containers_match

[find in source code]

def pass_if_containers_match(file_1, file_2):

Checks if file extensions match between two files. If they do it passes, is they don't it raises WrongContainer exception.

Arguments

• file_1 str - First file in comparison.
• file_2 str - Second file in comparison.

Raises

• WrongContainer - If file extensions (containers) mismatch.

quality_metrics

[find in source code]

def quality_metrics(original, processed, metric=None):

Compute video quality metrics between two video files for comparing the quality of video codecs or measuring the efficacy of encoding configuration. Possible to compute three major video quality metrics used for objective evaluation, namely:

• PSNR: It is the most commonly used video quality metric. But it has the lowest predictive value, so the results are inconsistent. Used by major platforms like Netflix and Facebook to compare different codecs and for similar use cases. Overall usage is declining.
• SSIM: Mostly used by technical experts like codec researchers and compression engineers. Usage is declining steadily. However, it has a higher predictive value than PSNR.
• VMAF: Introduced first by Netflix but then converted into an open-source asset. VMAF is easily accessible and widely used. Designed specifically for evaluating the video quality of streams encoded for multiple-resolution rungs.

Arguments

• original str - Path to the original/reference video file.
• processed str - Path to the processed/distorted video file.
• metric str, optional - Type of quality metric to compute ('vmaf', 'ssim', or 'psnr'). Defaults to None (which computes all the metrics).

rotate_video

[find in source code]

def rotate_video(filename, angle, target_name=None, overwrite=False):

Rotates a video by an angle using ffmpeg.

Arguments

• filename str - Path to the input video file.
• angle float - The angle (in degrees) specifying the amount of rotation. Positive values rotate clockwise.
• target_name str, optional - Target filename as path. Defaults to None (which assumes that the input filename with the suffix "_rot" should be used).
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - The path to the rotated video file.

roundup

[find in source code]

def roundup(num, modulo_num):

Rounds up a number to the next integer multiple of another.

Arguments

• num int - The number to round up.
• modulo_num int - The number whose next integer multiple we want.

Returns

• int - The rounded-up number.

scale_array

[find in source code]

def scale_array(array, out_low, out_high):

Scales an array linearly.

Arguments

• array arraylike - The array to be scaled.
• out_low float - Minimum of output range.
• out_high float - Maximum of output range.

Returns

• arraylike - The scaled array.

scale_num

[find in source code]

def scale_num(val, in_low, in_high, out_low, out_high):

Scales a number linearly.

Arguments

• val float - The value to be scaled.
• in_low float - Minimum of input range.
• in_high float - Maximum of input range.
• out_low float - Minimum of output range.
• out_high float - Maximum of output range.

Returns

• float - The scaled number.

str2sec

[find in source code]

def str2sec(time_string):

Converts a time code string into seconds.

Arguments

• time_string str - The time code to convert. Eg. '01:33:42'.

Returns

• float - The time code converted to seconds.

threshold_ffmpeg

[find in source code]

def threshold_ffmpeg(
    filename,
    threshold=0.1,
    target_name=None,
    binary=False,
    overwrite=False,
):

Renders a pixel-thresholded video from the input using ffmpeg.

Arguments

• filename str - Path to the input video file.
• threshold float, optional - The normalized pixel value to use as the threshold. Pixels below the threshold will turn black. Defaults to 0.1.
• target_name str, optional - The name of the output video. Defaults to None (which assumes that the input filename with the suffix "_thresh" should be used).
• binary bool, optional - If True, the pixels above the threshold will turn white. Defaults to False.
• overwrite bool, optional - Whether to allow overwriting existing files or to automatically increment target filename to avoid overwriting. Defaults to False.

Returns

• str - Path to the output video.

unwrap_str

[find in source code]

def unwrap_str(string):

Unwraps a string from quotes.

Arguments

• string str - The string to inspect.

Returns

• str - The (unwrapped) string.

wrap_str

[find in source code]

def wrap_str(string, matchers=[' ', '(', ')']):

Wraps a string in double quotes if it contains any of matchers - by default: space or parentheses. Useful when working with shell commands.

Arguments

• string str - The string to inspect.
• matchers list, optional - The list of characters to look for in the string. Defaults to [" ", "(", ")"].

Returns

• str - The (wrapped) string.