API Reference¶

Decoder¶

This is the main class that retrieves video and audio frames from MoviePy/ffmpeg. You can supply Decoder with callback functions that handle stream data once it is available.

class mediadecoder.decoder.Decoder(mediafile=None, videorenderfunc=None, play_audio=True)[source]¶

This class loads a video file that can be played. It can be passed a callback function to which decoded video frames should be passed.

Attributes

current_frame_no	Current frame_no of video.
current_playtime	Clocks current runtime in seconds.
current_videoframe	Representation of current video frame as a numpy array.
frame_interval	Duration in seconds of a single frame.
loop	Indicates whether the playback should loop.

Methods

load_media(mediafile[, play_audio])	Loads a media file to decode.
pause()	Pauses or resumes the video and/or audio stream.
play()	Start the playback of the video.
reset()	Resets the player and discards loaded data.
rewind()	Rewinds the video to the beginning.
seek(value)	Seek to the specified time.
set_audiorenderer(renderer)	Sets the SoundRenderer object.
set_videoframerender_callback(func)	Sets the function to call when a new frame is available.
stop()	Stops the video stream and resets the clock.

__init__(mediafile=None, videorenderfunc=None, play_audio=True)[source]¶

Constructor.

Parameters:

mediafile : str, optional The path to the mediafile to be loaded (default: None) videorenderfunc : callable (default: None) Callback function that takes care of the actual Rendering of the videoframe. The specified renderfunc should be able to accept the following arguments: frame (numpy.ndarray): the videoframe to be rendered play_audio : bool, optional Whether audio of the clip should be played.

current_frame_no¶

Current frame_no of video.

current_playtime¶

Clocks current runtime in seconds.

current_videoframe¶

Representation of current video frame as a numpy array.

frame_interval¶

Duration in seconds of a single frame.

load_media(mediafile, play_audio=True)[source]¶

Loads a media file to decode.

If an audiostream is detected, its parameters will be stored in a dictionary in the variable audioformat. This contains the fields

Nbytes:	the number of bytes in the stream (2 is 16-bit sound).
Nchannels:	the channels (2 for stereo, 1 for mono)
Fps:	the frames per sec/sampling rate of the sound (e.g. 44100 KhZ).
Buffersize:	the audioframes per buffer.

If play_audio was set to False, or the video does not have an audiotrack, audioformat will be None.

Parameters:	mediafile : str The path to the media file to load. play_audio : bool, optional Indicates whether the audio of a movie should be played.
Raises:	IOError When the file could not be found or loaded.

loop¶

Indicates whether the playback should loop.

pause()[source]¶

Pauses or resumes the video and/or audio stream.

play()[source]¶

Start the playback of the video. The playback loop is run in a separate thread, so this function returns immediately. This allows one to implement things such as event handling loops (e.g. check for key presses) elsewhere.

reset()[source]¶

Resets the player and discards loaded data.

rewind()[source]¶

Rewinds the video to the beginning. Convenience function simply calling seek(0).

seek(value)[source]¶

Seek to the specified time.

Parameters:	value : str or int The time to seek to. Can be any of the following formats: >>> 15.4 -> 15.4 # seconds >>> (1,21.5) -> 81.5 # (min,sec) >>> (1,1,2) -> 3662 # (hr, min, sec) >>> '01:01:33.5' -> 3693.5 #(hr,min,sec) >>> '01:01:33.045' -> 3693.045 >>> '01:01:33,5' #comma works too

set_audiorenderer(renderer)[source]¶

Sets the SoundRenderer object. This should take care of processing the audioframes set in audioqueue.

Parameters:	renderer : soundrenderers.SoundRenderer A subclass of soundrenderers.SoundRenderer that takes care of the audio rendering.
Raises:	RuntimeError If no information about the audiostream is available. This could be because no video has been loaded yet, or because no embedded audiostream could be detected in the video, or play_sound was set to False.

set_videoframerender_callback(func)[source]¶

Sets the function to call when a new frame is available. This function is passed the frame (in the form of a numpy.ndarray) and should take care of the rendering.

Parameters:	func : callable The function to pass the new frame to once it becomes available.

stop()[source]¶

Stops the video stream and resets the clock.

Timer¶

class mediadecoder.timer.Timer(fps=None, max_duration=None)[source]¶

Timer serves as a video clock that is used to determine which frame needs to be displayed at a specified time. the clock runs in its own separate thread. Say you have an instance of Timer called clock. The time can be polled by checking

>> clock.time

and the current frame can be determined by checking

>> clock.current_frame.

Attributes

current_frame	The current frame number that should be displayed.
fps	Returns the frames per second indication that is currently set.
frame_interval	The duration of a single frame in seconds.
max_duration	Returns the max duration the clock should run for.
time	The current time of the clock.

Methods

pause()	Pauses the clock to continue running later.
reset()	Reset the clock to 0.
start()	Starts the clock from 0.
stop()	Stops the clock and resets the internal timers.

__init__(fps=None, max_duration=None)[source]¶

Constructor.

Parameters:	fps : float, optional The frames per second of the video for which this timer is created. max_duration : float, optional The maximum time in seconds the timer should run for.

current_frame¶

The current frame number that should be displayed.

fps¶

Returns the frames per second indication that is currently set.

frame_interval¶

The duration of a single frame in seconds.

max_duration¶

Returns the max duration the clock should run for. (Usually the duration of the videoclip)

pause()[source]¶

Pauses the clock to continue running later. Saves the duration of the current interval in the previous_intervals list.

reset()[source]¶

Reset the clock to 0.

start()[source]¶

Starts the clock from 0. Uses a separate thread to handle the timing functionalities.

stop()[source]¶

Stops the clock and resets the internal timers.

time¶

The current time of the clock.

Sound renderers¶

This module contains objects that handle the audio frames supplied by Decoder. At the moment, the only ones that are stable are the PyAudioSoundRenderer and SounddeviceSoundrenderer (which both are bindings to PortAudio.