Question

这是一个每秒提取视频提供帧图像的命令

ffmpeg -i "vide.mp4" -vf fps=1 frames/frame_%04d.png -hide_banner

ffmpeg中是否有一个命令用于剪切提供fps的视频并将其保存为视频（.mp4 / avi）文件，如上面的命令？

我现在拥有的是我创建了一种用开始和结束时间剪切视频的方法，但我首先创建了一种获取视频长度的方法，这样我就可以根据视频生成的帧数来剪切视频。以上命令。

 def get_length(self):
        """
        Gets the length of a video in seconds

        Returns:
            float : Length of the video
        """

        print("Getting video length: " + self.video_string_path)
        command = 'ffprobe -i "'+self.video_string_path+'" -show_entries format=duration -v quiet -of csv="p=0"'
        self.command = command
        length = str(cmd.execute(command)).strip()
        print("lenght: "+length+" second(s)")
        return float(length)

def cut(self, start_time, duration, output_file_name = 'output_file_name.mp4', save_to =''):
        """
        Cut a video on a specific start time of the video and duration.
        Check ffmpeg documentation https://ffmpeg.org/ffmpeg.html for more information about the parameters

        Parameters:
            start_time : string
                is the value of ffmpeg -ss with the format: 00:00:00.000

            duration : string | int | float
                is the end point where the video will be cut. Can be the same with start_time format but it could also handle integer as in seconds

            output_file_name : string
                is the file name once the file is save in the hardisk

            save_to : string | optional
                is the directory where the file will be saved

        Returns:
            string: file location of the cutted video

        """

        self.make_sure_save_dir_exits(save_to)
        print('Cutting ' + self.video_string_path + ' from ' + start_time + ' to ' + str(duration))
        print('Please wait...')
        file = '"' + self.save_to + output_file_name + '"'
        command = 'ffmpeg -i "' + self.video_string_path + '" -ss ' + str(start_time) + ' -t ' + str(duration) + ' -c copy -y ' + file
        self.command = command
        cmd.execute(command)

        file_loc = self.get_save_to_dir() + output_file_name
        print('Done: Output file was saved to "' + file_loc + '"')

        return file_loc + output_file_name

Answer 1

使用

ffmpeg -ss {start_time} -t {duration} -i "vide.mp4" -vf fps=X -c:a copy out.mp4

其中X是输出帧速率。

要分割整个文件，

ffmpeg -i "vide.mp4" -vf fps=X
  -f segment -segment_time {duration} -force_key_frames expr:gte(t,n_forced*{duration}) 
  -reset_timestamps 1 -segment_time_delta 1.0 -c:a copy out%d.mp4

Answer 2

将视频拆分为较小块的另一种方法是使用以下命令。

ffmpeg -i somefile.mp3 -f segment -segment_time 3 -c copy out%03d.mp3

https://www.ffmpeg.org/ffmpeg-formats.html#segment_002c-stream_005fsegment_002c-ssegment

ffmpeg用帧persecond分解视频

2 个答案: