MoviePy ValueError: t_start (60.00) should be smaller than the clip's duration (30.00)

Question

I'm using moviepy to cut a clip into multiple equally-sized segments, and it's reading from a txt file of start and end values to cut the clip properly. The following is my code:

required_video_file = VideoFileClip(filename)
with open("times.txt") as f:
  times = f.readlines()
times = [x.strip() for x in times] 
for time in times:
  starttime = int(time.split("-")[0])
  endtime = int(time.split("-")[1])
  required_video_file = required_video_file.subclip(starttime, endtime)
  filen = str(times.index(time)+1)+".mp4"
  required_video_file.write_videofile(filen, audio_codec='aac')

The current filename value is a 20-ish minute clip which has the times.txt file cut up into 30-second portions.

0-30
30-60
60-90
90-120
120-150

And so on. However, I get a valueerror when it tries to write the third file:

ValueError: t_start (60.00) should be smaller than the clip's duration (30.00).

I'm not sure why this error is happening, because the clip it's trying to create a subclip of is 20 minutes long, not 30 seconds.

FULL ERROR:

<moviepy.video.io.VideoFileClip.VideoFileClip object at 0x105e589a0>
Traceback (most recent call last):
  File "vidsplitter.py", line 76, in <module>
    required_video_file = required_video_file.subclip(starttime, endtime)
  File "<decorator-gen-35>", line 2, in subclip
  File "/Users/hypnoticocelot/Library/Python/3.8/lib/python/site-packages/moviepy/decorators.py", line 89, in wrapper
    return f(*new_a, **new_kw)
  File "<decorator-gen-34>", line 2, in subclip
  File "/Users/hypnoticocelot/Library/Python/3.8/lib/python/site-packages/moviepy/decorators.py", line 32, in apply_to_mask
    newclip = f(clip, *a, **k)
  File "<decorator-gen-33>", line 2, in subclip
  File "/Users/hypnoticocelot/Library/Python/3.8/lib/python/site-packages/moviepy/decorators.py", line 43, in apply_to_audio
    newclip = f(clip, *a, **k)
  File "/Users/hypnoticocelot/Library/Python/3.8/lib/python/site-packages/moviepy/Clip.py", line 391, in subclip
    raise ValueError(
ValueError: t_start (60.00) should be smaller than the clip's duration (30.00).

Answer 1

All problem can be because you assing new clip to the same variable

required_video_file = required_video_file.subclip(...)

so in next loop it uses shorter clip - with duration 30s.

You should use different variable

new_clip = required_video_file.subclip(...)

---

EDIT:

You should get full duration at start

full_duration = required_video_file.duration

and inside loop you should check if endtime is not too big and crop it.

    if endtime > full_duration:
        endtime = full_duration

You should also check if starttime is not too big and skip rest of code.

    if startime > full_duration:
        break  # exit `for`-loop

---

I would do (with some other changes)

required_video_file = VideoFileClip(filename)

full_duration = required_video_file.duration

with open("times.txt") as f:
    times = [x.strip().split('-') for x in f]

for number, (start, end) in enumerate(times, 1):
    starttime = int(start)
    endtime   = int(end)
    
    if starttime > full_duration:
        print(f"video too short to get {startime}-{endtime} (full duration: {full_duration})")
        break  # exit `for`-loop
    
    if endtime > full_duration:
        print(f"crop endtime {endtime} to {full_duration}")
        endtime = full_duration
    
    new_clip = required_video_file.subclip(starttime, endtime)
    
    new_filename = f"{number}.mp4"
    
    new_clip.write_videofile(new_filename, audio_codec='aac')