Module `generativepy.movie`

The movie consists of a sequence of frames, where each frame is a NumPy array. Movies are generated and processed using a lazy iterators tht generates frames on demand.

The movie module provides functionality to create video clips (or "scenes"), incorporate audio files, and compile separate scenes into complete movies.

Functions

def create_videoclip(frames, duration, frame_rate, audio_in=None)

Create a VideoClip object from a sequence of frames and an optional audio file.

Args

frames: numpy arrays - the sequence of frames.
duration: number - duration of clip in seconds.
frame_rate: number - frame rate, frames per second.
audio_in: str - file name of audio file, or None.

Returns

A VideoClip object.

def duplicate_frame(frame, count)

Duplicate a single frame, multiple times.

Args

frame: numpy array - the frame
count: int - Number of times to duplicate

Returns

A generator object.

def normalise_array(array)

If greyscale array has a shape [a, b, 1] it must be normalised to [a, b] otherwise the pillow fromarray function will give an error.

This function first checks if normalisation is necessary, and then creates a new normalised array if required.

Args

array: numpy array - the image data as a numpy array.

Returns

Normalised array. This will either be a new array (if normalisation was required) or the original array (if no normalisation was required).

def save_frame(outfile, frame)

Save a frame as a png image

Args

outfile: str - full name and path of the file (.png extension optional)
frame: numpy array - the frame

def save_frames(outfile, frames)

Save a sequence of frame as a sequence of png images

Args

outfile: str - base name and path of the file (.png extension optional).
frames: numpy arrays - the sequence of frames.

Classes

class MovieBuilder (frame_rate)

Builds up a movie from a set of clips.

Args

frame_rate: number - frame rate, frames per second.

Expand source code

class MovieBuilder():
    """
    Builds up a movie from a set of clips.
    """

    def __init__(self, frame_rate):
        """
        Args:
            frame_rate: number - frame rate, frames per second.
        """
        self.frame_rate = frame_rate
        self.frame_sources = []
        self.audio_files = []
        self.duration = []

    def add_scene(self, frame_source_duration, audio_file=None):
        """
        Add a scene (a sequence of frame plus an optional audio file).

        Note, due to the requirements of the MoviePy library, if the movie has sound then every scene must include a sound file (use
        a slient file if no sound is required for a particular scene). Alternatively, if the movie has no sound,then don;t include
        a sound file with any of the scenes.

        Also note that the sound file should be at least as long as the video duration.

        Args:
            frame_source_duration: tuple - frame_source, duration. frame_source is a iterator returning
                numpy frame objects, duration is the clip duration in seconds
            audio_file: str - name of MP3 file, or None.

        Returns:

        """
        self.frame_sources.append(frame_source_duration[0])
        self.duration.append(frame_source_duration[1])
        self.audio_files.append(audio_file)

    def make_movie(self, video_out, source=None):
        """
        Make a movie of either all the clips that have been added, or just a single clip if source is not None.

        Args:
            video_out: str - Filename of output file.
            source: int - set to index of a clip to use just that clip, or None to join all clips.
        """
        if source is not None:
            video = create_videoclip(self.frame_sources[source], self.duration[source], self.frame_rate, self.audio_files[source])
        else:
            clips = [create_videoclip(s, d, self.frame_rate, a) for s, d, a in zip(self.frame_sources, self.duration, self.audio_files)]
            video = concatenate_videoclips(clips)

        # Due to a bug in moviepy 1.0.1, when we write a video out in this mode the audio is not included.
        # So we write the video and audio out to separate temporary files.
        # We then use ffmpeg directly to combine the video and audio.
        temp_video_filename = temp_file(pathlib.Path(video_out).stem + "TEMP.mp4")
        temp_audio_filename = temp_file(pathlib.Path(video_out).stem + "TEMP.m4a")

        if not all(self.audio_files):
            if any(self.audio_files):
                logging.warning("MovieBuilder - some of the scenes have audio data, some do not, so the final video will have no audio data")
            video.write_videofile(video_out, codec="libx264", fps=self.frame_rate)
        else:
            video.write_videofile(temp_video_filename, temp_audiofile=temp_audio_filename, codec="libx264",
                                  remove_temp=False, audio_codec="aac", fps=self.frame_rate)

            command = ["ffmpeg",
                       "-y", #approve output file overwite
                       "-i", temp_video_filename,
                       "-i", temp_audio_filename,
                       "-c:v", "copy",
                       "-c:a", "copy",
                       "-shortest",
                       "-r", str(self.frame_rate),
                       video_out ]
            process = sp.run(command)

Methods

def add_scene(self, frame_source_duration, audio_file=None)

Add a scene (a sequence of frame plus an optional audio file).

Note, due to the requirements of the MoviePy library, if the movie has sound then every scene must include a sound file (use a slient file if no sound is required for a particular scene). Alternatively, if the movie has no sound,then don;t include a sound file with any of the scenes.

Also note that the sound file should be at least as long as the video duration.

Args

frame_source_duration: tuple - frame_source, duration. frame_source is a iterator returning numpy frame objects, duration is the clip duration in seconds
audio_file: str - name of MP3 file, or None.

Returns:

def make_movie(self, video_out, source=None)

Make a movie of either all the clips that have been added, or just a single clip if source is not None.

Args

video_out: str - Filename of output file.
source: int - set to index of a clip to use just that clip, or None to join all clips.