使用moviepy进行多处理

Question

最近我做了一个脚本，需要 5 分钟的视频剪辑并剪切 5 个视频，每个视频 1 分钟，效果很好，但是对于像我这样的电脑来说太长了，而且我的电脑具有非常好的部分性能：

Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz, 2904 Mhz, 8 Core(s), 16 Logical Processor(s)

安装物理 Memory (RAM) 16.0 GB

所以我搜索了moviepy的文档“threads”，我在“write_videofile”function 中找到了一些东西，我可以设置我的线程来加快速度，我试过了，但它没有用，我的意思是它有效，但它唯一的改变可能是更多 2 或 3 it/s。

我还找到了多线程的示例代码，但似乎代码不起作用，因为moviepy库中不存在moviepy.multithreading，请帮我加快渲染速度，谢谢

这是我找到的代码：

from moviepy.multithreading import multithread_write_videofile

def concat_clips():
    files = [
        "myclip1.mp4",
        "myclip2.mp4",
        "myclip3.mp4",
        "myclip4.mp4",
    ]
    multithread_write_videofile("output.mp4", get_final_clip, {"files": files})


def get_final_clip(files):
    clips = [VideoFileClip(file) for file in files]
    final = concatenate_videoclips(clips, method="compose")
    return final

这是我的代码：

from moviepy.video.io.ffmpeg_tools import ffmpeg_extract_subclip
from moviepy.editor import *
from numpy import array, true_divide
import cv2
import time


# ffmpeg_extract_subclip("full.mp4", start_seconds, end_seconds, targetname="cut.mp4")




def duration_clip(filename):
    clip = VideoFileClip(filename)
    duration = clip.duration
    return duration


current_time = time.strftime("%Y_%m_%d_%H_%M_%S")


def main():
    global duration
    start = 0
    cut_name_num = 1
    end_seconds = start + 60
    video_duration = duration_clip("video.mp4")
    


    txt = input("Enter Your text please: ") [::-1]
    txt_part = 1

    while start < int(video_duration):
        final_text = f"{str(txt_part)} {txt}"



        try:
            try:
                os.makedirs(f"result_{str(current_time)}/result_edit")
            except FileExistsError:
                pass            
            ffmpeg_extract_subclip("video.mp4", start, end_seconds, targetname=f"result_{str(current_time)}/cut_{str(cut_name_num)}.mp4")

            clip = VideoFileClip(f"result_{str(current_time)}/cut_{str(cut_name_num)}.mp4")

            clip = clip.subclip(0, 60)

            clip = clip.volumex(2)

            txt_clip = TextClip(final_text, font="font/VarelaRound-Regular.ttf", fontsize = 50, color = 'white')

            txt_clip = txt_clip.set_pos(("center","top")).set_duration(60) 

            video = CompositeVideoClip([clip, txt_clip])
            
            clip.write_videofile(f"result_{str(current_time)}/result_edit/cut_{str(cut_name_num)}.mp4")

        except:
            try:
                os.makedirs(f"result_{str(current_time)}/result_edit")
            except FileExistsError:
                pass
            
            ffmpeg_extract_subclip("video.mp4", start, video_duration, targetname=f"result_{str(current_time)}/cut_{str(cut_name_num)}.mp4")

            clip_duration = duration_clip(f"result_{str(current_time)}/cut_{str(cut_name_num)}.mp4")

            clip = VideoFileClip(f"result_{str(current_time)}/cut_{str(cut_name_num)}.mp4")

            clip = clip.subclip(0, clip_duration)

            clip = clip.volumex(2)

            txt_clip = TextClip(final_text, font="font/VarelaRound-Regular.ttf", fontsize = 50, color = 'white')

            txt_clip = txt_clip.set_pos(("center","top")).set_duration(60) 

            video = CompositeVideoClip([clip, txt_clip])

            clip.write_videofile(f"result_{str(current_time)}/result_edit/cut_{str(cut_name_num)}.mp4")

        start += 60
        cut_name_num += 1
        end_seconds = start + 60
        txt_part += 1


if __name__ == "__main__":
    main()

Answer 1

使用进程我只减少了 15-20 秒的时间，因为ffmpeg即使在单个进程中也使用了几乎全部的 CPU 能力，而我的计算机没有能力更快地运行其他进程。

---

首先，我减少了代码以使其更短。

try和except中的代码具有相似的元素，所以我将它们移到try/except 。

接下来我用

        if end > video_duration:
            end = video_duration

而且我根本不需要try/except 。

使用os.makedirs(..., exist_ok=True)我不需要在try/except中运行它

同时，我使用减少了 20 秒的时间

        clip = VideoFileClip(filename).subclip(start, end)

代替

        temp_filename  = f"{base_folder}/cut_{number}.mp4"
        
        fmpeg_extract_subclip(filename, start, end, targetname=temp_filename)
        
        clip = VideoFileClip(temp_filename)

这样我就不用在磁盘上写子剪辑，也不必从磁盘再次读取它。

---

from moviepy.video.io.ffmpeg_tools import ffmpeg_extract_subclip
from moviepy.editor import *
import time

def main():

    text = input("Enter Your text please: ") [::-1]
    #text = 'Hello World'
    
    base_folder = time.strftime("result_%Y_%m_%d_%H_%M_%S")    
    os.makedirs(f"{base_folder}/result_edit", exist_ok=True)
    
    filename = "video.mp4"
    #filename = "BigBuckBunny.mp4"
    
    video_duration = VideoFileClip(filename).duration

    number = 0 # instead of `cut_name_num` and `txt_part` because both had the same value

    time_start = time.time()

    for start in range(0, int(video_duration), 60):

        end = start + 60
        
        if end > video_duration:
            end = video_duration

        number += 1

        clip_duration = end - start
        print(f'[DEBUG] number: {number:2} | start: {start:6.2f} | end: {end:6.2f} | duration: {clip_duration:.2f}')
       
        final_text = f"{number} {text}"
    
        temp_filename  = f"{base_folder}/cut_{number}.mp4"
        final_filename = f"{base_folder}/result_edit/cut_{number}.mp4"
        
        #ffmpeg_extract_subclip(filename, start, end, targetname=temp_filename)
        
        #clip = VideoFileClip(temp_filename)
        clip = VideoFileClip(filename).subclip(start, end)
        clip = clip.volumex(2)
    
        txt_clip = TextClip(final_text, font="font/VarelaRound-Regular.ttf", fontsize=50, color='white')
        txt_clip = txt_clip.set_pos(("center","top")).set_duration(60)
        
        video = CompositeVideoClip([clip, txt_clip])
    
        video.write_videofile(final_filename)

    # - after loop -
    
    # because I use `number += 1` before loop so now `number` has number of subclips
    print('number of subclips:', number)

    time_end = time.time()
    
    diff = time_end - time_start
    print(f'time: {diff:.2f}s ({diff//60:02.0f}:{diff%60:02.2f})')
    
    
if __name__ == "__main__":
    main()

接下来，我使用 arguments my_process(filename, text, start, end, number, base_folder)将代码移动到 function

from moviepy.video.io.ffmpeg_tools import ffmpeg_extract_subclip
from moviepy.editor import *
import time

def my_process(filename, text, start, end, number, base_folder):

    clip_duration = end - start
    print(f'[DEBUG] number: {number:2} | start: {start:6.2f} | end: {end:6.2f} | duration: {clip_duration:.2f}')
    
    final_text = f"{number} {text}"

    temp_filename  = f"{base_folder}/cut_{number}.mp4"
    final_filename = f"{base_folder}/result_edit/cut_{number}.mp4"
    
    #print('[DEBUG] ffmpeg_extract_subclip')
    #ffmpeg_extract_subclip(filename, start, end, targetname=temp_filename)
    
    #print('[DEBUG] VideoClip')
    #clip = VideoFileClip(temp_filename)
    clip = VideoFileClip(filename).subclip(start, end)
    clip = clip.volumex(2)

    #print('[DEBUG] TextClip')
    txt_clip = TextClip(final_text, font="font/VarelaRound-Regular.ttf", fontsize=50, color='white')
    txt_clip = txt_clip.set_pos(("center","top")).set_duration(60)
    
    #print('[DEBUG] CompositeVideoClip')
    video = CompositeVideoClip([clip, txt_clip])

    #print('[DEBUG] CompositeVideoClip write')
    video.write_videofile(final_filename)
    #print('[DEBUG] CompositeVideoClip end')
    

def main():

    text = input("Enter Your text please: ") [::-1]
    #text = 'Hello World'
    
    base_folder = time.strftime("result_%Y_%m_%d_%H_%M_%S")    
    os.makedirs(f"{base_folder}/result_edit", exist_ok=True)
    
    filename = "video.mp4"
    #filename = "BigBuckBunny.mp4"
    
    video_duration = VideoFileClip(filename).duration

    number = 0 # instead of `cut_name_num` and `txt_part` because both had the same value

    time_start = time.time()
    
    for start in range(0, int(video_duration), 60):

        end = start + 60
        
        if end > video_duration:
            end = video_duration
        
        number += 1
        
        my_process(filename, text, start, end, number, base_folder)
        
    # - after loop -
    
    # because I use `number += 1` before loop so now `number` has number of subclips
    print('number of subclips:', number)

    time_end = time.time()
    
    diff = time_end - time_start
    print(f'time: {diff:.2f}s ({diff//60:02.0f}:{diff%60:02.2f})')


if __name__ == "__main__":
    main()

现在我可以使用标准模块多处理在分离的进程中运行 function

（或标准模块threading 、 concurrent.futures或外部模块Joblib 、 Ray等）。

它启动单个进程

# it has to use named arguments`target=`, `args=`

p = multiprocessing.Process(target=my_process, args=(filename, text, start, end, number, base_folder))
p.start()  # start it

但是如果我在循环中使用它，那么我将同时启动许多进程。

---

from moviepy.video.io.ffmpeg_tools import ffmpeg_extract_subclip
from moviepy.editor import *
import time
import multiprocessing

def my_process(filename, text, start, end, number, base_folder):

    clip_duration = end - start
    print(f'[DEBUG] number: {number:2} | start: {start:6.2f} | end: {end:6.2f} | duration: {clip_duration:.2f}')
    
    final_text = f"{number} {text}"

    temp_filename  = f"{base_folder}/cut_{number}.mp4"
    final_filename = f"{base_folder}/result_edit/cut_{number}.mp4"
    
    #print('[DEBUG] ffmpeg_extract_subclip')
    #ffmpeg_extract_subclip(filename, start, end, targetname=temp_filename)
    
    #print('[DEBUG] VideoClip')
    #clip = VideoFileClip(temp_filename)
    clip = VideoFileClip(filename).subclip(start, end)
    clip = clip.volumex(2)

    #print('[DEBUG] TextClip')
    txt_clip = TextClip(final_text, font="font/VarelaRound-Regular.ttf", fontsize=50, color='white')
    txt_clip = txt_clip.set_pos(("center","top")).set_duration(60)
    
    #print('[DEBUG] CompositeVideoClip')
    video = CompositeVideoClip([clip, txt_clip])

    #print('[DEBUG] CompositeVideoClip write')
    video.write_videofile(final_filename)
    #print('[DEBUG] CompositeVideoClip end')
    

def main():

    text = input("Enter Your text please: ") [::-1]
    #text = 'Hello World'
    
    base_folder = time.strftime("result_%Y_%m_%d_%H_%M_%S")    
    os.makedirs(f"{base_folder}/result_edit", exist_ok=True)
    
    filename = "video.mp4"
    #filename = "BigBuckBunny.mp4"
    
    video_duration = VideoFileClip(filename).duration

    number = 0 # instead of `cut_name_num` and `txt_part` because both had the same value

    time_start = time.time()
    
    all_processes = []
    for start in range(0, int(video_duration), 60):

        end = start + 60
        
        if end > video_duration:
            end = video_duration
        
        number += 1
        
        print("add process:", number)
        p = multiprocessing.Process(target=my_process, args=(filename, text, start, end, number, base_folder)) # it has to use `target=`, `args=`
        p.start()  # start it
        all_processes.append(p)  # keep it to use `join()`
            
    # - after loop -
    
    for p in all_processes:
        p.join()  # wait for the end of process
        
    # because I use `number += 1` before loop so now `number` has number of subclips
    print('number of subclips:', number)

    time_end = time.time()
    
    diff = time_end - time_start
    print(f'time: {diff:.2f}s ({diff//60:02.0f}:{diff%60:02.2f})')


if __name__ == "__main__":
    main()

---

11 个子剪辑的先前版本启动 11 个进程。 使用Pool(4)您可以将所有进程放入池中，它将同时运行 4 个进程。 当一个进程完成任务时，它将使用新的 arguments 启动下一个进程。

这次我使用循环为所有进程创建带有 arguments 的列表

args_for_all_processes = []

for start in range(0, int(video_duration), 60):

    end = start + 60
    
    if end > video_duration:
        end = video_duration
    
    number += 1
    print("add process:", number)
    
    args_for_all_processes.append( (filename, text, start, end, number, base_folder) )

我将此列表与Pool一起使用，它将执行 rest。

# I have 4 CPU so I use Pool(4) - but without value it should automatically use `os.cpu_count()`
with multiprocessing.Pool(4) as pool:      
    results = pool.starmap(my_process, args_for_all_processes)
    #print(results)

Pool可能以不同的顺序启动进程，但如果它们使用return发送一些结果，则Pool将以正确的顺序给出结果。

from moviepy.video.io.ffmpeg_tools import ffmpeg_extract_subclip
from moviepy.editor import *
import time
import multiprocessing

def my_process(filename, text, start, end, number, base_folder):

    clip_duration = end - start
    print(f'[DEBUG] number: {number:2} | start: {start:6.2f} | end: {end:6.2f} | duration: {clip_duration:.2f}')
    
    final_text = f"{number} {text}"

    temp_filename  = f"{base_folder}/cut_{number}.mp4"
    final_filename = f"{base_folder}/result_edit/cut_{number}.mp4"
    
    #print('[DEBUG] ffmpeg_extract_subclip')
    #ffmpeg_extract_subclip(filename, start, end, targetname=temp_filename)
    
    #print('[DEBUG] VideoClip')
    #clip = VideoFileClip(temp_filename)
    clip = VideoFileClip(filename).subclip(start, end)
    clip = clip.volumex(2)

    #print('[DEBUG] TextClip')
    txt_clip = TextClip(final_text, font="font/VarelaRound-Regular.ttf", fontsize=50, color='white')
    txt_clip = txt_clip.set_pos(("center","top")).set_duration(60)
    
    #print('[DEBUG] CompositeVideoClip')
    video = CompositeVideoClip([clip, txt_clip])

    #print('[DEBUG] CompositeVideoClip write')
    video.write_videofile(final_filename)
    #print('[DEBUG] CompositeVideoClip end')
    
    # return "OK"  # you can use `return` to send result/information to main process.
    
def main():

    text = input("Enter Your text please: ") [::-1]
    #text = 'Hello World'
    
    base_folder = time.strftime("result_%Y_%m_%d_%H_%M_%S")    
    os.makedirs(f"{base_folder}/result_edit", exist_ok=True)
    
    filename = "video.mp4"
    #filename = "BigBuckBunny.mp4"
    
    video_duration = VideoFileClip(filename).duration

    number = 0 # instead of `cut_name_num` and `txt_part` because both had the same value

    time_start = time.time()
    
    # first create list with arguments for all processes
    
    args_for_all_processes = []
    
    for start in range(0, int(video_duration), 60):

        end = start + 60
        
        if end > video_duration:
            end = video_duration
        
        number += 1
        print("add process:", number)
        
        args_for_all_processes.append( (filename, text, start, end, number, base_folder) )

    # - after loop -            
        
    # next put all processes to pool
        
    with multiprocessing.Pool(4) as pool:  # I have 4 CPU so I use Pool(4) - but it should use `os.cpu_count()` in `Pool()
    
        results = pool.starmap(my_process, args_for_all_processes)
        #print(results)
            
    # - after loop -
    
    # because I use `number += 1` before loop so now `number` has number of subclips
    print('number of subclips:', number)

    time_end = time.time()
    
    diff = time_end - time_start
    print(f'time: {diff:.2f}s ({diff//60:02.0f}:{diff%60:02.2f})')


if __name__ == "__main__":
    main()