make_frame(t) after concatenation

[timpauli]

First of all I wanted to say what a cool project moviepy is and thank everyone who participated in it.

I wrote an algorithm using moviepy which cuts a clip in very tiny bits and applies different effects to it and then concatenates them back together.

Sometimes I get this error message while rendering in the end:

  File "<decorator-gen-51>", line 2, in write_videofile
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 54, in requires_duration
    return f(clip, *a, **k)
  File "<decorator-gen-50>", line 2, in write_videofile
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 137, in use_clip_fps_by_default
    return f(clip, *new_a, **new_kw)
  File "<decorator-gen-49>", line 2, in write_videofile
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 22, in convert_masks_to_RGB
    return f(clip, *a, **k)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/video/VideoClip.py", line 349, in write_videofile
    progress_bar=progress_bar)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/video/io/ffmpeg_writer.py", line 209, in ffmpeg_write_video
    fps=fps, dtype="uint8"):
  File "/usr/local/lib/python3.5/dist-packages/tqdm/_tqdm.py", line 833, in __iter__
    for obj in iterable:
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 475, in generator
    frame = self.get_frame(t)
  File "<decorator-gen-14>", line 2, in get_frame
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 95, in get_frame
    return self.make_frame(t)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/video/compositing/concatenate.py", line 83, in make_frame
    return clips[i].get_frame(t - tt[i])
  File "<decorator-gen-14>", line 2, in get_frame
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 95, in get_frame
    return self.make_frame(t)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 136, in <lambda>
    newclip = self.set_make_frame(lambda t: fun(self.get_frame, t))
  File "/usr/local/lib/python3.5/dist-packages/moviepy/video/VideoClip.py", line 533, in <lambda>
    return self.fl(lambda gf, t: image_func(gf(t)), apply_to)
  File "<decorator-gen-14>", line 2, in get_frame
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 95, in get_frame
    return self.make_frame(t)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 136, in <lambda>
    newclip = self.set_make_frame(lambda t: fun(self.get_frame, t))
  File "/usr/local/lib/python3.5/dist-packages/moviepy/video/VideoClip.py", line 533, in <lambda>
    return self.fl(lambda gf, t: image_func(gf(t)), apply_to)
  File "<decorator-gen-14>", line 2, in get_frame
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 95, in get_frame
    return self.make_frame(t)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 136, in <lambda>
    newclip = self.set_make_frame(lambda t: fun(self.get_frame, t))
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 188, in <lambda>
    return self.fl(lambda gf, t: gf(t_func(t)), apply_to,
  File "<decorator-gen-14>", line 2, in get_frame
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 95, in get_frame
    return self.make_frame(t)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 136, in <lambda>
    newclip = self.set_make_frame(lambda t: fun(self.get_frame, t))
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 188, in <lambda>
    return self.fl(lambda gf, t: gf(t_func(t)), apply_to,
  File "<decorator-gen-14>", line 2, in get_frame
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 95, in get_frame
    return self.make_frame(t)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 136, in <lambda>
    newclip = self.set_make_frame(lambda t: fun(self.get_frame, t))
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 188, in <lambda>
    return self.fl(lambda gf, t: gf(t_func(t)), apply_to,
  File "<decorator-gen-14>", line 2, in get_frame
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 95, in get_frame
    return self.make_frame(t)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 136, in <lambda>
    newclip = self.set_make_frame(lambda t: fun(self.get_frame, t))
  File "/usr/local/lib/python3.5/dist-packages/moviepy/video/VideoClip.py", line 533, in <lambda>
    return self.fl(lambda gf, t: image_func(gf(t)), apply_to)
  File "<decorator-gen-14>", line 2, in get_frame
  File "/usr/local/lib/python3.5/dist-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/Clip.py", line 95, in get_frame
    return self.make_frame(t)
  File "/usr/local/lib/python3.5/dist-packages/moviepy/video/compositing/concatenate.py", line 83, in make_frame
    return clips[i].get_frame(t - tt[i])
IndexError: list index out of range

Unfortunately I cant narrow it down to a minimal example that repoduces it but in
concatenate.py in line 82 the make_frame(t)-method tries to find out which of the concatenated clips it has to use for the current frame. For this it enumerates over tt but tt has always one item more than there are clips because of its creation in line 71. So in some cases (which exactly I dont fully understand) it reaches this last index which leads to the error above.

You can see that when you make an explicit call to make_frame(t) after concatenation:

from moviepy.editor import concatenate_videoclips

def concatenate_make_frame_error(inputclip):
    concatenate_videoclips([inputclip, inputclip]).make_frame(inputclip.duration * 2)

A quick fix which seems to break nothing would be to adjust line 82 to i = max([i for i, e in zip(range(len(tt) - 1), tt) if e <= t]). So to just skip the last entry for the enumeration.

[llazzaro]

Hi,

I hit the same issue when the subtitles time is outside the video limits.
For example in a video of 10 seconds, if I use a subtitle from (9, 11) I got the same traceback.

Here is a sample code to reproduce the bug:

subs = [
        ((9,1 1), 'sub1'),
]
subtitles = SubtitlesClip(subs, generator)
 cvc = CompositeVideoClip(
        [final_clip, subtitles.set_pos(('center', 'bottom'))],
        use_bgclip=True
    )
    cvc.write_videofile('bug.mp4', fps=30, audio_codec="aac")

Hope it helps!
I could try to fix this issue with a pull request in the future

[tburrows13]

Hey @llazzaro, I tried, but I couldn't replicate your crash. For me, the background clip just stopped for a second before the video finished.

Even though you are getting an IndexError, this is definitely a different issue, so would you mind opening a new issue with more details (such as the clip that you are using as final_clip)?

[llazzaro]

@tburrows13 I will try to open a new issue with a test to reproduce the bug, thanks!