def ffmpeg_resize(video,output,size):
    """ resizes ``video`` to new size ``size`` and write the result
        in file ``output``. """
    cmd= [get_setting("FFMPEG_BINARY"), "-i", video, "-vf", "scale=%d:%d"%(size[0], size[1]),
             output]
             
    subprocess_call(cmd)

def ffmpeg_resize(video,output,size):
    """ resizes ``video`` to new size ``size`` and write the result
        in file ``output``. """
    cmd= ["ffmpeg", "-i", video, "-vf", "scale=%d:%d"%(res[0], res[1]),
             output]
             
    subprocess_call(cmd)

def gif_to_directory(gif_file,dirName=None):
    """
    Stores all the frames of the given .gif file
    into the directory ``dirName``. If ``dirName``
    is not provided, the directory has the same name
    as the .gif file. Supports transparency.
    Returns the directory name.

    Example:

    >>> d = gif_to_directory("animated-earth.gif")
    >>> clip = DirectoryClip(d,fps=3)

    """

    if dirName is None:
        name, ext = os.path.splitext(gif_file)
        dirName = name

    try:
        os.mkdir(dirName)
    except:
        pass

    subprocess_call(["convert", "-coalesce", gif_file,
             os.path.join(dirName,"%04d.png")])

def ffmpeg_merge_video_audio(video,audio,output,
                vcodec='copy', acodec='copy', ffmpeg_output=False):
    """ merges video file ``video`` and audio file ``audio`` into one
        movie file ``output``. """
    cmd = ["ffmpeg", "-y", "-i", audio,"-i", video,
             "-vcodec", vcodec, "-acodec", acodec, output]
             
    subprocess_call(cmd, stdin=None, stdout=None)

    def __init__(self, txt, size=None, color='black',
             bg_color='transparent', fontsize=None, font='Courier',
             stroke_color=None, stroke_width=1, method='label',
             kerning=None, align='center', interline=None,
             tempfile='temp.png', temptxt='temp.txt',
             transparent=True, remove_temp=True,
             print_cmd=False):

        if not txt.startswith('@'):
            temptxt = 'temp.txt'
            with open(temptxt, 'w+') as f:
                f.write(txt)
            txt = '@temp.txt'
        else:
            txt = "'%s'"%txt

        if size != None:
            size = ('' if size[0] is None else str(size[0]),
                    '' if size[1] is None else str(size[1]))

        cmd = ( ["convert",
               "-background", bg_color,
               "-fill", color,
               "-font", font])
            
        if fontsize !=None:
            cmd += ["-pointsize", "%d"%fontsize]
        if kerning != None:
            cmd += ["-kerning", "%0.1f"%kerning]
        if stroke_color != None:
            cmd += ["-stroke", stroke_color, "-strokewidth",
                                             "%.01f"%stroke_width]
        if size != None:
            cmd += ["-size", "%sx%s"%(size[0], size[1])]
        if align != None:
            cmd += ["-gravity",align]
        if interline != None:
            cmd += ["-interline-spacing", "%d"%interline]
            
        cmd += ["%s:%s" %(method, txt),
        "-type",  "truecolormatte", "PNG32:%s"%tempfile]
        
        if print_cmd:
            print( " ".join(cmd) )

        subprocess_call(cmd, verbose=False )
        
        ImageClip.__init__(self, tempfile, transparent=transparent)
        self.txt = txt
        self.color = color
        self.stroke_color = stroke_color

        if remove_temp:
            os.remove(tempfile)
            try:
                os.remove(temptxt)
            except:
                pass

def ffmpeg_merge_video_audio(video,audio,output, vcodec='copy',
                             acodec='copy', ffmpeg_output=False,
                             logger = 'bar'):
    """ merges video file ``video`` and audio file ``audio`` into one
        movie file ``output``. """
    cmd = [get_setting("FFMPEG_BINARY"), "-y", "-i", audio,"-i", video,
             "-vcodec", vcodec, "-acodec", acodec, output]
             
    subprocess_call(cmd, logger = logger)

def ffmpeg_merge_video_audio(video,audio,output, vcodec='copy',
                             acodec='copy', ffmpeg_output=False,
                             verbose = True):
    """ merges video file ``video`` and audio file ``audio`` into one
        movie file ``output``. """
    cmd = [FFMPEG_BINARY, "-y", "-i", audio,"-i", video,
             "-vcodec", vcodec, "-acodec", acodec, output]
             
    subprocess_call(cmd, verbose = verbose)

def download_webfile(url, filename, overwrite=False):
    """ Small utility to download the file at 'url' under name 'filename'.
    If url is a youtube video ID like z410eauCnH it will download the video
    using youtube-dl (install youtube-dl first !).
    If the filename already exists and overwrite=False, nothing will happen.
    """
    if os.path.exists(filename) and not overwrite:
        return

    if '.' in url:
        urlretrieve(url, filename)
    else:
        subprocess_call(['youtube-dl', url, '-o', filename])

def ffmpeg_movie_from_frames(filename, folder, fps, digits=6):
    """
    Writes a movie out of the frames (picture files) in a folder.
    Almost deprecated.
    """
    s = "%" + "%02d" % digits + "d.png"
    cmd = ["ffmpeg", "-y", "-f","image2",
             "-r", "%d"%fps,
             "-i", os.path.join(folder,folder) + '/' + s,
             "-b", "%dk"%bitrate,
             "-r", "%d"%self.fps,
             filename]
    
    subprocess_call(cmd, stdin=None, stdout=None)

def ffmpeg_movie_from_frames(filename, folder, fps, digits=6, bitrate='v'):
    """
    Writes a movie out of the frames (picture files) in a folder.
    Almost deprecated.
    """
    s = "%" + "%02d" % digits + "d.png"
    cmd = [get_setting("FFMPEG_BINARY"), "-y", "-f","image2",
             "-r", "%d"%fps,
             "-i", os.path.join(folder,folder) + '/' + s,
             "-b", "%dk"%bitrate,
             "-r", "%d"%fps,
             filename]
    
    subprocess_call(cmd)

def ffmpeg_extract_subclip(filename, t1, t2, targetname=None):
    """ Makes a new video file playing video file ``filename`` between
        the times ``t1`` and ``t2``. """
    name, ext = os.path.splitext(filename)
    if not targetname:
        T1, T2 = [int(1000*t) for t in [t1, t2]]
        targetname = "%sSUB%d_%d.%s" % (name, T1, T2, ext)
    
    cmd = [get_setting("FFMPEG_BINARY"),"-y",
           "-ss", "%0.2f"%t1,
           "-i", filename,
           "-t", "%0.2f"%(t2-t1),
           "-vcodec", "copy", "-acodec", "copy", targetname]
    
    subprocess_call(cmd)

def download_webfile(url, filename, overwrite=False):
    """ Small utility to download the file at 'url' under name 'filename'.
    If url is a youtube video ID like z410eauCnH it will download the video
    using youtube-dl (install youtube-dl first !).
    If the filename already exists and overwrite=False, nothing will happen.
    """
    if os.path.exists(filename) and not overwrite:
        return

    if '.' in url:
        urlretrieve(url, filename)
    else:
        try:
            subprocess_call(['youtube-dl', url, '-o', filename])
        except OSError as e:
            raise OSError(e.message + '\n A possible reason is that youtube-dl'
                ' is not installed on your computer. Install it with '
                ' "pip install youtube-dl"')

def download_webfile(url, filename, overwrite=False):
    """ Small utility to download the file at 'url' under name 'filename'.
    If url is a youtube video ID like z410eauCnH it will download the video
    using youtube-dl (install youtube-dl first !).
    If the filename already exists and overwrite=False, nothing will happen.
    """
    if os.path.exists(filename) and not overwrite:
        return

    if '.' in url:
        r = requests.get(url, stream=True)
        with open(filename, 'wb') as fd:
            for chunk in r.iter_content(chunk_size=128):
                fd.write(chunk)

    else:
        try:
            subprocess_call(['youtube-dl', url, '-o', filename])
        except OSError as e:
            raise OSError(
                e.message + '\n A possible reason is that youtube-dl'
                ' is not installed on your computer. Install it with '
                ' "pip install youtube_dl"')

    def __init__(self, txt, size=None, color='black',
             bg_color='transparent', fontsize=None, font='Courier',
             stroke_color=None, stroke_width=1, method='label',
             kerning=None, align='center', interline=None,
             tempfilename=None, temptxt=None,
             transparent=True, remove_temp=True,
             print_cmd=False):

        if not txt.startswith('@'):
            if temptxt is None:
                temptxt_fd, temptxt = tempfile.mkstemp(suffix='.txt')
                os.write(temptxt_fd, txt)
                os.close(temptxt_fd)
            txt = '@'+temptxt
        else:
            txt = "'%s'"%txt

        if size != None:
            size = ('' if size[0] is None else str(size[0]),
                    '' if size[1] is None else str(size[1]))

        cmd = ( [IMAGEMAGICK_BINARY,
               "-background", bg_color,
               "-fill", color,
               "-font", font])

        if fontsize !=None:
            cmd += ["-pointsize", "%d"%fontsize]
        if kerning != None:
            cmd += ["-kerning", "%0.1f"%kerning]
        if stroke_color != None:
            cmd += ["-stroke", stroke_color, "-strokewidth",
                                             "%.01f"%stroke_width]
        if size != None:
            cmd += ["-size", "%sx%s"%(size[0], size[1])]
        if align != None:
            cmd += ["-gravity",align]
        if interline != None:
            cmd += ["-interline-spacing", "%d"%interline]

        if tempfilename is None:
            tempfile_fd, tempfilename = tempfile.mkstemp(suffix='.png')
            os.close(tempfile_fd)

        cmd += ["%s:%s" %(method, txt),
        "-type",  "truecolormatte", "PNG32:%s"%tempfilename]

        if print_cmd:
            print( " ".join(cmd) )

        subprocess_call(cmd, verbose=False )

        ImageClip.__init__(self, tempfilename, transparent=transparent)
        self.txt = txt
        self.color = color
        self.stroke_color = stroke_color

        if remove_temp:
            if os.path.exists(tempfilename):
                os.remove(tempfilename)
            if os.path.exists(temptxt):
                os.remove(temptxt)

    def to_gif(self, filename, fps=None, program= 'ImageMagick',
            opt="OptimizeTransparency", fuzz=1, verbose=True,
            loop=0, dispose=False):
        """ Write the VideoClip to a GIF file
        Converts a VideoClip into an animated GIF using ImageMagick or
        ffmpeg.


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

        filename
          Name of the resulting gif file.

        fps
          Number of frames per second (see note below). If it
            isn't provided, then the function will look for the clip's
            ``fps`` attribute (VideoFileClip, for instance, have one).

        program
          Software to use for the conversion, either 'ImageMagick' or
          'ffmpeg'.

        opt
          (ImageMagick only) optimalization to apply, either
          'optimizeplus' or 'OptimizeTransparency'.

        fuzz
          (ImageMagick only) Compresses the GIF by considering that the
          colors that are less than fuzz% different are in fact the same.


        Notes
        -----

        The gif will be playing the clip in real time (you can
        only change the frame rate). If you want the gif to be played
        slower than the clip you will use ::

            >>> # slow down clip 50% and make it a gif
            >>> myClip.speedx(0.5).to_gif('myClip.gif')

        """

        def verbose_print(s):
            if verbose: sys_write_flush(s)

        if fps is None:
            fps = self.fps

        fileName, fileExtension = os.path.splitext(filename)
        tt = np.arange(0,self.duration, 1.0/fps)
        tempfiles = []

        verbose_print("\nMoviePy: building GIF file %s\n"%filename
                      +40*"-"+"\n")

        verbose_print("Generating GIF frames.\n")

        total = int(self.duration/fps)+1
        for i, t in tqdm(enumerate(tt), total=total):

            name = "%s_GIFTEMP%04d.png"%(fileName, i+1)
            tempfiles.append(name)
            self.save_frame(name, t, savemask=True)

        verbose_print("Done generating GIF frames.\n")

        delay = int(100.0/fps)

        if program == "ImageMagick":

            cmd = [IMAGEMAGICK_BINARY,
                  '-delay' , '%d'%delay,
                  "-dispose" ,"%d"%(2 if dispose else 1),
                  "-loop" , "%d"%loop,
                  "%s_GIFTEMP*.png"%fileName,
                  "-coalesce",
                  "-fuzz", "%02d"%fuzz + "%",
                  "-layers", "%s"%opt,
                  "%s"%filename]

        elif program == "ffmpeg":

            cmd = [FFMPEG_BINARY, '-y',
                   '-f', 'image2',
                   '-i', fileName+'_GIFTEMP%04d.png',
                   '-r',str(fps),
                   filename]


        subprocess_call( cmd, verbose = verbose )

        for f in tempfiles:
            os.remove(f)

    def __init__(self, txt=None, filename=None, size=None, color='black',
                 bg_color='transparent', fontsize=None, font='Courier',
                 stroke_color=None, stroke_width=1, method='label',
                 kerning=None, align='center', interline=None,
                 tempfilename=None, temptxt=None,
                 transparent=True, remove_temp=True,
                 shadow=None, antialias=4,
                 print_cmd=False):

        import tempfile
        import subprocess as sp

        from moviepy.tools import subprocess_call
        from moviepy.config import get_setting

        # from moviepy.video.VideoClip import *

        aa_factor= 1 if not antialias else antialias

        if txt is not None:
            if temptxt is None:
                temptxt_fd, temptxt = tempfile.mkstemp(suffix='.txt')
                try:  # only in Python3 will this work
                    os.write(temptxt_fd, bytes(txt, 'UTF8'))
                except TypeError:  # oops, fall back to Python2
                    os.write(temptxt_fd, txt)
                os.close(temptxt_fd)
            txt = '@' + temptxt
        else:
            # use a file instead of a text.
            txt = "@%" + filename

        if size is not None:
            size = ('' if size[0] is None else size[0],
                    '' if size[1] is None else size[1])

        if shadow is not None:
            shadow = (80 if shadow[0] is None else shadow[0],
                       1 if shadow[1] is None else shadow[1],
                       2 if shadow[2] is None else shadow[2],
                       2 if shadow[3] is None else shadow[3])

        cmd = ( [get_setting("IMAGEMAGICK_BINARY"),
               "-density", str(aa_scale(72, aa_factor)),
               "-background", bg_color,
               "-fill", color,
               "-font", font])

        if fontsize is not None:
            cmd += ["-pointsize", "%d" % fontsize]
        if kerning is not None:
            cmd += ["-kerning", "%0.1f" % aa_scale(kerning, aa_factor)]
        if stroke_color is not None:
            cmd += ["-stroke", stroke_color, "-strokewidth",
                    "%.01f" % aa_scale(stroke_width, aa_factor)]
        if size is not None:
            cmd += ["-size", "%sx%s" % aa_scale(size, aa_factor)]
        if align is not None:
            cmd += ["-gravity", align]
        if interline is not None:
            cmd += ["-interline-spacing", "%d" % interline]

        if tempfilename is None:
            tempfile_fd, tempfilename = tempfile.mkstemp(suffix='.png')
            os.close(tempfile_fd)

        if shadow is not None:
            shadow_cmd = ( ["(", "+clone",
                          "-shadow", "%sx%s+%s+%s" % (tuple([shadow[0]]) + aa_scale(shadow[1:], aa_factor)),
                          ")",
                          "-compose", "DstOver",
                          "-flatten"])

        cmd += ["%s:%s" % (method, txt)]
        cmd += shadow_cmd
        cmd += ["-resample", "72"]
        cmd += ["-type", "truecolormatte", "PNG32:%s" % tempfilename]

        if print_cmd:
            print( " ".join(cmd) )

        try:
            subprocess_call(cmd, verbose=verbose)
        except (IOError,OSError) as err:
            error = ("MoviePy Error: creation of %s failed because "
              "of the following error:\n\n%s.\n\n."%(filename, str(err))
               + ("This error can be due to the fact that "
                    "ImageMagick is not installed on your computer, or "
                    "(for Windows users) that you didn't specify the "
                    "path to the ImageMagick binary in file conf.py, or."
                    "that the path you specified is incorrect" ))
            raise IOError(error)

        ImageClip.__init__(self, tempfilename, transparent=transparent)
        self.txt = txt
        self.color = color
        self.stroke_color = stroke_color

        if remove_temp:
            if os.path.exists(tempfilename):
#.........这里部分代码省略.........

def write_gif_with_tempfiles(clip, filename, fps=None, program= 'ImageMagick',
       opt="OptimizeTransparency", fuzz=1, verbose=True,
       loop=0, dispose=True, colors=None):
    """ Write the VideoClip to a GIF file.


    Converts a VideoClip into an animated GIF using ImageMagick
    or ffmpeg. Does the same as write_gif (see this one for more
    docstring), but writes every frame to a file instead of passing
    them in the RAM. Useful on computers with little RAM.

    """

    fileName, fileExtension = os.path.splitext(filename)
    tt = np.arange(0,clip.duration, 1.0/fps)

    tempfiles = []

    verbose_print(verbose, "\n[MoviePy] Building file %s\n"%filename
                  +40*"-"+"\n")

    verbose_print(verbose, "[MoviePy] Generating GIF frames...\n")

    total = int(clip.duration*fps)+1
    for i, t in tqdm(enumerate(tt), total=total):

        name = "%s_GIFTEMP%04d.png"%(fileName, i+1)
        tempfiles.append(name)
        clip.save_frame(name, t, withmask=True)

    delay = int(100.0/fps)

    if program == "ImageMagick":
        verbose_print(verbose, "[MoviePy] Optimizing GIF with ImageMagick... ")
        cmd = [get_setting("IMAGEMAGICK_BINARY"),
              '-delay' , '%d'%delay,
              "-dispose" ,"%d"%(2 if dispose else 1),
              "-loop" , "%d"%loop,
              "%s_GIFTEMP*.png"%fileName,
              "-coalesce",
              "-layers", "%s"%opt,
              "-fuzz", "%02d"%fuzz + "%",
              ]+(["-colors", "%d"%colors] if colors is not None else [])+[
              filename]

    elif program == "ffmpeg":

        cmd = [get_setting("FFMPEG_BINARY"), '-y',
               '-f', 'image2', '-r',str(fps),
               '-i', fileName+'_GIFTEMP%04d.png',
               '-r',str(fps),
               filename]

    try:
        subprocess_call( cmd, verbose = verbose )
        verbose_print(verbose, "[MoviePy] GIF %s is ready."%filename)

    except (IOError,OSError) as err:

        error = ("MoviePy Error: creation of %s failed because "
          "of the following error:\n\n%s.\n\n."%(filename, str(err)))

        if program == "ImageMagick":
            error = error + ("This error can be due to the fact that "
                "ImageMagick is not installed on your computer, or "
                "(for Windows users) that you didn't specify the "
                "path to the ImageMagick binary in file conf.py." )

        raise IOError(error)

    for f in tempfiles:
        os.remove(f)

def ffmpeg_extract_audio(inputfile,output,bitrate=3000,fps=44100):
    """ extract the sound from a video file and save it in ``output`` """
    cmd = ["ffmpeg", "-y", "-i", inputfile, "-ab", "%dk"%bitrate,
         "-ar", "%d"%fps, output]
    subprocess_call(cmd, stdin=None, stdout=None)

def ffmpeg_extract_audio(inputfile,output,bitrate=3000,fps=44100):
    """ extract the sound from a video file and save it in ``output`` """
    cmd = [get_setting("FFMPEG_BINARY"), "-y", "-i", inputfile, "-ab", "%dk"%bitrate,
         "-ar", "%d"%fps, output]
    subprocess_call(cmd)