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• Configure FFmpeg to save the recording at specified time intervals as separate output files

  27 septembre 2023, par John Doe

  How can I configure FFmpeg to save the recording into separate output files at specific time intervals, for example, every 25 seconds without interrupting the recording ? By default, FFmpeg saves the entire recorded video in a single output file, but I want to create separate output files for each 25-second segment.
What steps should I follow to achieve this ?

  


  I tried python multiprogramming to run the recording and saving task simultanously but didn't work.

  


  How about using the @ffmpeg.on("progress") event ?

  


• concatdec : change data type to suppress warning about limited range of data type...

  17 décembre 2012, par Michael Niedermayer

  concatdec : change data type to suppress warning about limited range of data type...

• What do I need in order to save animation videos from matplotlib in mp3 format ?

  27 juin 2022, par DarthMalloc

  I am using python3.8 on Linux Mint 19.3, and I am trying to save an animation created by a cellular automata model in matplotlib. My actual code for the model is private, but it uses the same code for saving the animation as the code shown below, which is a slight modification of one of the examples shown in the official matplotlib documentation :

  


  import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation

fig, ax = plt.subplots()


def f(x, y):
    return np.sin(x) + np.cos(y)

x = np.linspace(0, 2 * np.pi, 120)
y = np.linspace(0, 2 * np.pi, 100).reshape(-1, 1)

fig, ax = plt.subplots()


    
ims = []
for i in range(60):
    x += np.pi / 15.
    y += np.pi / 20.
    im = ax.imshow(f(x, y), animated=True)
    if i == 0:
        ax.imshow(f(x, y))  # show an initial one first
    ims.append([im])

ani = animation.ArtistAnimation(fig, ims, interval=50, blit=True,
                                    repeat_delay=1000)

    # To save the animation, use e.g.
    #
    # ani.save("movie.mp4")
    #
    # or
    #
writer = animation.FFMpegWriter(fps=15, metadata=dict(artist='Me'), bitrate=1800)
ani.save("movie.mp3", writer=writer)


  


  When executed, the code produces this error :

  


      MovieWriter stderr:&#xA;    Output file #0 does not contain any stream&#xA;&#xA;    Traceback (most recent call last):&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/animation.py", line 234, in saving&#xA;        yield self&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/animation.py", line 1093, in save&#xA;        writer.grab_frame(**savefig_kwargs)&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/animation.py", line 351, in grab_frame&#xA;        self.fig.savefig(self._proc.stdin, format=self.frame_format,&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/figure.py", line 3046, in savefig&#xA;        self.canvas.print_figure(fname, **kwargs)&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/backend_bases.py", line 2319, in print_figure&#xA;        result = print_method(&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/backend_bases.py", line 1648, in wrapper&#xA;        return func(*args, **kwargs)&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/_api/deprecation.py", line 415, in wrapper&#xA;        return func(*inner_args, **inner_kwargs)&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/backends/backend_agg.py", line 486, in print_raw&#xA;        fh.write(renderer.buffer_rgba())&#xA;    BrokenPipeError: [Errno 32] Broken pipe&#xA;&#xA;    During handling of the above exception, another exception occurred:&#xA;&#xA;    Traceback (most recent call last):&#xA;      File "/home/justin/animation_test.py", line 36, in <module>&#xA;        ani.save("movie.mp3", writer=writer)&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/animation.py", line 1093, in save&#xA;        writer.grab_frame(**savefig_kwargs)&#xA;      File "/usr/lib/python3.8/contextlib.py", line 131, in __exit__&#xA;        self.gen.throw(type, value, traceback)&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/animation.py", line 236, in saving&#xA;        self.finish()&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/animation.py", line 342, in finish&#xA;        self._cleanup()  # Inline _cleanup() once cleanup() is removed.&#xA;      File "/usr/local/lib/python3.8/dist-packages/matplotlib/animation.py", line 373, in _cleanup&#xA;        raise subprocess.CalledProcessError(&#xA;    subprocess.CalledProcessError: Command &#x27;[&#x27;ffmpeg&#x27;, &#x27;-f&#x27;, &#x27;rawvideo&#x27;, &#x27;-vcodec&#x27;, &#x27;rawvideo&#x27;, &#x27;-s&#x27;, &#x27;640x480&#x27;, &#x27;-pix_fmt&#x27;, &#x27;rgba&#x27;, &#x27;-r&#x27;, &#x27;15&#x27;, &#x27;-loglevel&#x27;, &#x27;error&#x27;, &#x27;-i&#x27;, &#x27;pipe:&#x27;, &#x27;-vcodec&#x27;, &#x27;h264&#x27;, &#x27;-pix_fmt&#x27;, &#x27;yuv420p&#x27;, &#x27;-b&#x27;, &#x27;1800k&#x27;, &#x27;-metadata&#x27;, &#x27;artist=Me&#x27;, &#x27;-y&#x27;, &#x27;movie.mp3&#x27;]&#x27; returned non-zero exit status 1.&#xA;</module>

  


  I have looked at posts on similar queries concerning matplotlib animations, but none have specifically included the error Output file #0 does not contain any stream. I have little experience with ffmpeg, so I am wondering what might be missing.