Python:分割影片為指定長度

人們經常在通訊軟體分享各種多媒體訊息，而影片長度或檔案大小可能會有上傳限制，只好將其分割成多個片段上傳。就Line而言，我查到的資訊是限制影片長度5分鐘內、檔案大小300MB以下，就能順利傳送並於聊天室中播放。短片的話自己手動分割一下就行了，但你知道的(?)，有些人分享的片段完整加總起來都數十分鐘甚至一個多小時，仔細觀察那些片段的長度竟然都不一樣，而且還有上字(XXX分享之類的)，這…還真是吃力不討好啊，我只能說祝大大一生平安🙆‍♂️。

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還是交給程式來處理吧，指定影片分割秒數，並自動在片頭上字持續3秒做為順序標記。此範例需用到moviepy套件，且需事先安裝FFmpeg和ImageMagick這兩個開源軟體。

#!/usr/bin/env python3
import moviepy.editor as mp


# e.g. video_split("./LaplaceTW.mp4", 300)
def video_split(filepath, duration):
    video = mp.VideoFileClip(filepath).resize(width=720)
    video_length = int(video.duration) # seconds
    parts = int(video_length / duration)
    remaining = video_length - (duration * parts)
    parts = (parts + 1) if remaining > 0 else parts
    print("Video Length:", video_length, " | Split Parts:", parts)

    start, end = 0, duration
    for part in range(1, parts + 1):
        title = "Part." + str(part)
        text = (mp.TextClip(title, fontsize=50, color='yellow')
            .set_pos(("right", "top"))
            .set_duration(3))

        clip = video.subclip(start, end)
        clip = mp.CompositeVideoClip([clip, text])
        clip.write_videofile(title + '.mp4')
        
        if part == parts - 1 and remaining > 0:
            start += duration
            end += remaining
        else:
            start += duration
            end += duration

分割長時間影片 ⬇︎

處理結果 ⬇︎

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＊若沒有安裝ImageMagick則會發生執行錯誤：[Errno 2] No such file or directory: ‘unset’: ‘unset’

OSError: MoviePy Error: creation of None failed because of the following error:

[Errno 2] No such file or directory: 'unset': 'unset'.

.This error can be due to the fact that ImageMagick is not installed on your computer, 
or (for Windows users) that you didn't specify the path to the ImageMagick binary in 
file conf.py, or that the path you specified is incorrect

Ref. TextClip Doesn’t work at all #1003