A dropin replacement for OpenCv::VideoWriter in python.

FFMPEG_Writer.py

"""
The MIT License (MIT)
[OSI Approved License]

The MIT License (MIT)

Copyright (c) 2015 Zulko

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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Source: https://github.com/Zulko/moviepy/blob/master/moviepy/video/io/ffmpeg_writer.py
http://zulko.github.io/blog/2013/09/27/read-and-write-video-frames-in-python-using-ffmpeg/
with modififactions

On the long term this will implement several methods to make videos
out of VideoClips
"""

import os
import numpy as np

from moviepy.compat import PY3, DEVNULL
from moviepy.config import get_setting
from subprocess_utils import sp


# noinspection PyPep8Naming
class FFMPEG_VideoWriter:
    """ A class for FFMPEG-based video writing.

    A class to write videos using ffmpeg. ffmpeg will write in a large
    choice of formats.

    Parameters
    -----------

    out_file_name
      Any filename like 'video.mp4' etc. but if you want to avoid
      complications it is recommended to use the generic extension
      '.avi' for all your videos.

    size
      Size (width,height) of the output video in pixels.

    fps
      Frames per second in the output video file.

    codec
      FFMPEG codec. It seems that in terms of quality the hierarchy is
      'rawvideo' = 'png' > 'mpeg4' > 'libx264'
      'png' manages the same lossless quality as 'rawvideo' but yields
      smaller files. Type ``ffmpeg -codecs`` in a terminal to get a list
      of accepted codecs.

      Note for default 'libx264': by default the pixel format yuv420p
      is used. If the video dimensions are not both even (e.g. 720x405)
      another pixel format is used, and this can cause problem in some
      video readers.

    audiofile
      Optional: The name of an audio file that will be incorporated
      to the video.

    preset
      Sets the time that FFMPEG will take to compress the video. The slower,
      the better the compression rate. Possibilities are: ultrafast,superfast,
      veryfast, faster, fast, medium (default), slow, slower, veryslow,
      placebo.

    bitrate
      Only relevant for codecs which accept a bitrate. "5000k" offers
      nice results in general.

    withmask
      Boolean. Set to ``True`` if there is a mask in the video to be
      encoded.

    """

    def __init__(self, out_file_name, size, fps, codec="libx264", audiofile=None,
                 preset="ultrafast", bitrate=None, withmask=False,
                 logfile=None, threads=None, ffmpeg_params=None):

        if logfile is None:
            logfile = sp.PIPE

        self.filename = out_file_name
        self.codec = codec
        self.ext = self.filename.split(".")[-1]

        # order is important
        cmd = [
            get_setting("FFMPEG_BINARY"),
            '-y',
            '-loglevel', 'error' if logfile == sp.PIPE else 'info',
            '-f', 'image2pipe',  # Source: https://trac.ffmpeg.org/wiki/Slideshow
            '-s', '%dx%d' % (size[0], size[1]),
            '-pix_fmt', 'rgba' if withmask else 'rgb24',
            '-r', '%.02f' % fps,
            '-i', '-', '-an',
        ]
        if audiofile is not None:
            cmd.extend([
                '-i', audiofile,
                '-acodec', 'copy'
            ])
        cmd.extend([
            '-vcodec', codec,
            '-preset', preset,
        ])
        if ffmpeg_params is not None:
            cmd.extend(ffmpeg_params)
        if bitrate is not None:
            cmd.extend([
                '-b', bitrate
            ])

        if threads is not None:
            cmd.extend(["-threads", str(threads)])

        if ((codec == 'libx264') and
                (size[0] % 2 == 0) and
                (size[1] % 2 == 0)):
            cmd.extend([
                '-pix_fmt', 'yuv420p'
            ])
        cmd.extend([
            out_file_name
        ])

        popen_params = {"stdout": DEVNULL,
                        "stderr": logfile,
                        "stdin": sp.PIPE}

        # This was added so that no extra unwanted window opens on windows
        # when the child process is created
        if os.name == "nt":
            popen_params["creationflags"] = 0x08000000  # CREATE_NO_WINDOW

        self.proc = sp.Popen(cmd, **popen_params)

    def write(self, img_array):
        """ Writes one frame in the file."""
        try:
            self.proc.stdin.write(img_array)
        except IOError as err:
            _, ffmpeg_error = self.proc.communicate()
            error = (str(err) + ("\n\nMoviePy error: FFMPEG encountered "
                                 "the following error while writing file %s:"
                                 "\n\n %s" % (self.filename, str(ffmpeg_error))))

            if b"Unknown encoder" in ffmpeg_error:

                error = error + ("\n\nThe video export "
                                 "failed because FFMPEG didn't find the specified "
                                 "codec for video encoding (%s). Please install "
                                 "this codec or change the codec when calling "
                                 "write_videofile. For instance:\n"
                                 "  >>> clip.write_videofile('myvid.webm', codec='libvpx')") % (self.codec)

            elif b"incorrect codec parameters ?" in ffmpeg_error:

                error = error + ("\n\nThe video export "
                                 "failed, possibly because the codec specified for "
                                 "the video (%s) is not compatible with the given "
                                 "extension (%s). Please specify a valid 'codec' "
                                 "argument in write_videofile. This would be 'libx264' "
                                 "or 'mpeg4' for mp4, 'libtheora' for ogv, 'libvpx for webm. "
                                 "Another possible reason is that the audio codec was not "
                                 "compatible with the video codec. For instance the video "
                                 "extensions 'ogv' and 'webm' only allow 'libvorbis' (default) as a"
                                 "video codec."
                                 ) % (self.codec, self.ext)

            elif b"encoder setup failed" in ffmpeg_error:

                error = error + ("\n\nThe video export "
                                 "failed, possibly because the bitrate you specified "
                                 "was too high or too low for the video codec.")

            elif b"Invalid encoder type" in ffmpeg_error:

                error = error + ("\n\nThe video export failed because the codec "
                                 "or file extension you provided is not a video")

            raise IOError(error)

    def release(self):
        if self.proc:
            self.proc.stdin.close()
            if self.proc.stderr is not None:
                self.proc.stderr.close()
            self.proc.wait()

        self.proc = None

    # Support the Context Manager protocol, to ensure that resources are cleaned up.

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self.close()


def ffmpeg_write_video(clip, filename, fps, codec="libx264", bitrate=None,
                       preset="medium", withmask=False, write_logfile=False,
                       audiofile=None, verbose=True, threads=None, ffmpeg_params=None,
                       logger='bar'):
    """ Write the clip to a videofile. See VideoClip.write_videofile for details
    on the parameters.
    """
    if write_logfile:
        logfile = open(filename + ".log", 'w+')
    else:
        logfile = None
    logger(message='Moviepy - Writing video %s\n' % filename)
    with FFMPEG_VideoWriter(filename, clip.size, fps, codec=codec,
                            preset=preset, bitrate=bitrate, logfile=logfile,
                            audiofile=audiofile, threads=threads,
                            ffmpeg_params=ffmpeg_params) as writer:

        nframes = int(clip.duration * fps)

        for t, frame in clip.iter_frames(logger=logger, with_times=True,
                                         fps=fps, dtype="uint8"):
            if withmask:
                mask = (255 * clip.mask.get_frame(t))
                if mask.dtype != "uint8":
                    mask = mask.astype("uint8")
                frame = np.dstack([frame, mask])

            writer.write_frame(frame)

    if write_logfile:
        logfile.close()
    logger(message='Moviepy - Done !')


def ffmpeg_write_image(filename, image, logfile=False):
    """ Writes an image (HxWx3 or HxWx4 numpy array) to a file, using
        ffmpeg. """

    if image.dtype != 'uint8':
        image = image.astype("uint8")

    cmd = [get_setting("FFMPEG_BINARY"), '-y',
           '-s', "%dx%d" % (image.shape[:2][::-1]),
           "-f", 'rawvideo',
           '-pix_fmt', "rgba" if (image.shape[2] == 4) else "rgb24",
           '-i', '-', filename]

    if logfile:
        log_file = open(filename + ".log", 'w+')
    else:
        log_file = sp.PIPE

    popen_params = {"stdout": DEVNULL,
                    "stderr": log_file,
                    "stdin": sp.PIPE}

    if os.name == "nt":
        popen_params["creationflags"] = 0x08000000

    proc = sp.Popen(cmd, **popen_params)
    out, err = proc.communicate(image.tostring())

    if proc.returncode:
        err = "\n".join(["[MoviePy] Running : %s\n" % cmd,
                         "WARNING: this command returned an error:",
                         err.decode('utf8')])
        raise IOError(err)

    del proc

    
# If you're using this class with python Wand, call this function on the image you want to write to the video

def convert_image_to_byte_array(frame):
    # https://www.oipapio.com/question-1738825
    img_array = numpy.asarray(bytearray(frame.make_blob()), dtype='uint8')
    return img_array