Error: wrong indices in video buffer. Maybe buffer too small.

The following code:

wordSlide = ColorClip((1280,720), (228,232,111))
wordText = TextClip(wordStr, font="Arial-Regular", color="YellowGreen", fontsize=90)
wordAudio = AudioFileClip(path + "word.aif")
wordClip = CompositeVideoClip([wordSlide.set_audio(wordAudio),
    wordText.set_pos('center')]).set_duration(wordAudio.duration)

Produces:

Error: wrong indices in video buffer. Maybe buffer too small.
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/local/Cellar/python/2.7.6_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "/usr/local/Cellar/python/2.7.6_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 763, in run
    self.__target(*self.__args, **self.__kwargs)
  File "<string>", line 2, in preview
  File "/usr/local/lib/python2.7/site-packages/moviepy/decorators.py", line 60, in requires_duration
    return f(clip, *a, **k)
  File "/usr/local/lib/python2.7/site-packages/moviepy/audio/io/preview.py", line 59, in preview
    sndarray = clip.to_soundarray(tt,nbytes)
  File "<string>", line 2, in to_soundarray
  File "/usr/local/lib/python2.7/site-packages/moviepy/decorators.py", line 60, in requires_duration
    return f(clip, *a, **k)
  File "/usr/local/lib/python2.7/site-packages/moviepy/audio/AudioClip.py", line 83, in to_soundarray
    snd_array = self.get_frame(tt)
  File "/usr/local/lib/python2.7/site-packages/moviepy/audio/AudioClip.py", line 189, in get_frame
    if (part is not False) ]
  File "/usr/local/lib/python2.7/site-packages/moviepy/audio/io/AudioFileClip.py", line 69, in <lambda>
    self.get_frame =  lambda t: self.reader.get_frame(t)
  File "/usr/local/lib/python2.7/site-packages/moviepy/audio/io/readers.py", line 173, in get_frame
    raise error
IndexError: index 45785 is out of bounds for axis 0 with size 45784

A little hack that kinda makes it go away is to do:

wordSlide = ColorClip((1280,720), (228,232,111))
wordText = TextClip(wordStr, font="Arial-Regular", color="YellowGreen", fontsize=90)
wordAudio = AudioFileClip(path + "word.aif")
wordClip = CompositeVideoClip([wordSlide.set_audio(wordAudio),
    wordText.set_pos('center')]).set_duration(wordAudio.duration - 0.01)

Although this doesn’t fix anything. It just happens to work in this case, but not for other clips. Why is it crashing?

The wordAudio.duration is 1.04s in this case. On some audio files it crashes, on some it doesn’t. Is this the accuracy problem with generating number of frames based on audio length?

[Zulko]

First, an update on your bugs.

At least on my computer, it seems that the main problem is that you ask the same clip to play three times, which forces the ffmpeg-reader to “rewind” or re-initialize, and that’s where the bug happens. You so that it is clearer:

# Won't work
video = concatenate([ wordClip.fadein(0.3),
                  spellingClip,
                  wordClip,    ###
                  meaningClip,
                  wordClip,    ###
                  exampleClip,
                  ending ])
# Will work
video = concatenate([ wordClip.fadein(0.3),
                  spellingClip,
                  meaningClip,
                  exampleClip,
                  ending ])

I will try to see what causes this bug. In the meantime, the most reliable solution is to create different entry points into the file:

clip1 = VideoFileClip("myvideo.mp4")
clip2 = VideoFileClip("myvideo.mp4")
clip3 = VideoFileClip("myvideo.mp4")

Since you need to process these clips afterwards, the best thing to do is to make a loop or a function, like this:

def make_wordClip(wordStr, wordFile):
wordSlide = ColorClip((1280,720), (178, 240, 120))
    wordText = TextClip(wordStr, font="Helvetica", color="#5782D4",
                    fontsize=90)
    wordAudio = AudioFileClip(wordFile, buffersize=4000)
    wordClip = CompositeVideoClip([wordSlide.set_audio(wordAudio),
                               wordText.set_pos('center')])\
           .set_duration(wordAudio.duration)
    return wordClip

wordClips = [make_wordClip(wordStr, "word.aif") for i in [1,2,3]]

#later 

video = concatenate([ wordClips[0].fadein(0.3),
                  spellingClip,
                  wordClips[1],    ###
                  meaningClip,
                  wordClips[2],    ###
                  exampleClip,
                  ending ])

[Netherdrake]

I have ran a couple hundred renderings, and I can confirm the bug is definitely fixed. Thank you very much! You’re awesome.