我有一系列的图片,我想从中创建一个视频。理想情况下,我可以为每帧指定帧持续时间,但固定的帧速率也可以。我在wxPython中这样做,所以我可以渲染到wxDC或我可以将图像保存到文件,如PNG。是否有一个Python库,将允许我创建一个视频(AVI, MPG等)或一个动画GIF从这些帧?

编辑:我已经尝试过PIL,它似乎不起作用。有人能用这个结论来纠正我吗?这个链接似乎支持我关于PIL的结论:http://www.somethinkodd.com/oddthinking/2005/12/06/python-imaging-library-pil-and-animated-gifs/


当前回答

正如上面提到的一个成员,imageio是一种很好的方法。imageio还允许你设置帧速率,我实际上用Python写了一个函数,允许你设置最后一帧的暂停。我将此函数用于科学动画,其中循环是有用的,但立即重新启动不是。下面是链接和函数:

如何使用Python制作GIF

import matplotlib.pyplot as plt
import os
import imageio

def gif_maker(gif_name,png_dir,gif_indx,num_gifs,dpi=90):
    # make png path if it doesn't exist already
    if not os.path.exists(png_dir):
        os.makedirs(png_dir)

    # save each .png for GIF
    # lower dpi gives a smaller, grainier GIF; higher dpi gives larger, clearer GIF
    plt.savefig(png_dir+'frame_'+str(gif_indx)+'_.png',dpi=dpi)
    plt.close('all') # comment this out if you're just updating the x,y data

    if gif_indx==num_gifs-1:
        # sort the .png files based on index used above
        images,image_file_names = [],[]
        for file_name in os.listdir(png_dir):
            if file_name.endswith('.png'):
                image_file_names.append(file_name)       
        sorted_files = sorted(image_file_names, key=lambda y: int(y.split('_')[1]))

        # define some GIF parameters

        frame_length = 0.5 # seconds between frames
        end_pause = 4 # seconds to stay on last frame
        # loop through files, join them to image array, and write to GIF called 'wind_turbine_dist.gif'
        for ii in range(0,len(sorted_files)):       
            file_path = os.path.join(png_dir, sorted_files[ii])
            if ii==len(sorted_files)-1:
                for jj in range(0,int(end_pause/frame_length)):
                    images.append(imageio.imread(file_path))
            else:
                images.append(imageio.imread(file_path))
        # the duration is the time spent on each image (1/duration is frame rate)
        imageio.mimsave(gif_name, images,'GIF',duration=frame_length)

其他回答

一个制作动图的简单函数:

import imageio
import pathlib
from datetime import datetime


def make_gif(image_directory: pathlib.Path, frames_per_second: float, **kwargs):
    """
    Makes a .gif which shows many images at a given frame rate.
    All images should be in order (don't know how this works) in the image directory

    Only tested with .png images but may work with others.

    :param image_directory:
    :type image_directory: pathlib.Path
    :param frames_per_second:
    :type frames_per_second: float
    :param kwargs: image_type='png' or other
    :return: nothing
    """
    assert isinstance(image_directory, pathlib.Path), "input must be a pathlib object"
    image_type = kwargs.get('type', 'png')

    timestampStr = datetime.now().strftime("%y%m%d_%H%M%S")
    gif_dir = image_directory.joinpath(timestampStr + "_GIF.gif")

    print('Started making GIF')
    print('Please wait... ')

    images = []
    for file_name in image_directory.glob('*.' + image_type):
        images.append(imageio.imread(image_directory.joinpath(file_name)))
    imageio.mimsave(gif_dir.as_posix(), images, fps=frames_per_second)

    print('Finished making GIF!')
    print('GIF can be found at: ' + gif_dir.as_posix())


def main():
    fps = 2
    png_dir = pathlib.Path('C:/temp/my_images')
    make_gif(png_dir, fps)

if __name__ == "__main__":
    main()

现在我在用ImageMagick。我将帧保存为PNG文件,然后从Python中调用ImageMagick的convert.exe来创建一个动画GIF。这种方法的好处是我可以为每一帧单独指定帧持续时间。不幸的是,这取决于ImageMagick安装在机器上。他们有一个Python包装器,但它看起来很糟糕,不受支持。还在考虑其他建议。

你试过PyMedia吗?我不是100%确定,但看起来这个教程的例子针对的是你的问题。

对我来说,使它工作的最简单的事情是在Python中调用shell命令。

如果您的图像存储为dummy_image_1.png, dummy_image_2.png…dummy_image_N.png,然后你可以使用函数:

import subprocess
def grid2gif(image_str, output_gif):
    str1 = 'convert -delay 100 -loop 1 ' + image_str  + ' ' + output_gif
    subprocess.call(str1, shell=True)

执行:

grid2gif("dummy_image*.png", "my_output.gif")

这将构造你的gif文件my_output.gif。

老问题,有很多很好的答案,但可能仍然对另一种选择感兴趣……

我最近在github (https://github.com/WarrenWeckesser/numpngw)上发布的numpngw模块可以从numpy数组写入动画PNG文件。(更新:numpngw现在在pypi: https://pypi.python.org/pypi/numpngw。)

例如,这个脚本:

import numpy as np
import numpngw


img0 = np.zeros((64, 64, 3), dtype=np.uint8)
img0[:32, :32, :] = 255
img1 = np.zeros((64, 64, 3), dtype=np.uint8)
img1[32:, :32, 0] = 255
img2 = np.zeros((64, 64, 3), dtype=np.uint8)
img2[32:, 32:, 1] = 255
img3 = np.zeros((64, 64, 3), dtype=np.uint8)
img3[:32, 32:, 2] = 255
seq = [img0, img1, img2, img3]
for img in seq:
    img[16:-16, 16:-16] = 127
    img[0, :] = 127
    img[-1, :] = 127
    img[:, 0] = 127
    img[:, -1] = 127

numpngw.write_apng('foo.png', seq, delay=250, use_palette=True)

创建:

你需要一个支持动画PNG的浏览器(直接或带有插件)才能看到动画。