Question

我正在尝试检测某个视频是否包含任何有效内容，或者只是标准的广播栏＆amp;音。到目前为止，我已经查看了这个问题：https://superuser.com/questions/1036449/detect-color-bars-ffmpeg/1036478#1036478 产生酒吧＆amp;第一帧的音调，然后将其与流的其余部分进行比较，但在我的情况下，我需要在一个只有一个文件的文件夹中运行ffmpeg命令，该文件已经被我的python脚本找到。

是否可以使用ffmpeg＆＃39; blend = difference来检查短条和＆amp;音调片段是我的一个视频文件的子片段？我正在考虑这个问题，就像检查一个字符串是否在一个字符串中一样，或者是否有更好的方法来检查我没想到的条形图？

谢谢！

Answer 1

我找到了一种让我的脚本用python和ffmpeg做我想做的事的方法：

有关此ffmpeg命令如何工作的信息： http://ffmpeg.org/ffmpeg-filters.html#Video-Filters question

----------------------------------------------- ---------开始代码--------------------------------------- ----------------

selection = "'gt(scene\,0.1)'"         # The decimal here is the threshold for determining video quality (0 -> 1)

proc5 = Popen('C:/ffmpeg/bin/ffmpeg.exe -i "'+ src +'" -vf "select='+ selection +'" -vsync 0 -f image2 -y //fn101cdmzst01.foxneo.com/signiant/foxsports/soundmouse/FileManagerInfo/Thumbnails/thumbnails-%02d.jpg 2>&1', stdout=PIPE, shell=True)  # This is the ffmpeg command.  The specifics of how it works are explained below

res, err = proc5.communicate()         # Read proc5's (the ffmpeg command) stdout to res and stderr to err

proc5.wait()                           # Wait for ffmpeg to finish processing the whole video file

res = str(res.decode('ascii'))         # Decode the ascii output from stdout and convert to a string

print(res)

if r"Output file is empty" in res:     # If the ascii output from stdout has the string "Output file is empty", remove it.  Otherwise, perform name changes and file move for soundmouse

----------------------------------------------- ------------ END CODE ------------------------------------ -------------------

FFMPEG COMMAND: 'C:/ffmpeg/bin/ffmpeg.exe -i "'+ src +'" -vf "select='+ selection +'" -vsync 0 -f image2 -y //fn101cdmzst01.foxneo.com/signiant/foxsports/soundmouse/FileManagerInfo/Thumbnails/thumbnails-%02d.jpg 2>&1'

实际的ffmpeg命令根据它执行的各种操作突出显示。

C:/ffmpeg/bin/ffmpeg.exe          # make an absolute path call to ffmpeg.exe

-i "'+ src +'"                    # set the absolute path to the source file as the input

-vf "select='+ selection +'"      # use a video filter to select frames with large change before and after (based on the decimal threshold that is set) and compare it with the following portion of the command

-vsync 0 -f image2 -y //fn101cdmzst01.foxneo.com/signiant/foxsports/soundmouse/FileManagerInfo/Thumbnails/thumbnails-%02d.jpg  # compare the selected frame with the previous one stored in the Thumbnails folder and then overwrite the comparison thumbnail with the selected frame for the next comparison

2>&1'                             # redirect stderr to stdout so that we can read it with Python's proc5.communicate() function

FFMPEG检测视频中的彩条和色调

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