拉长视频时长的两种方法

系统导入错误“ImportError:无法导入名称‘Moviepy.editor’“的解决办法

方法一：

from moviepy.editor import VideoFileClip
import os

def slow_down_video(input_path, output_path, target_duration):
    """
    通过放慢视频速度将视频调整到指定时长

    参数:
    input_path: 输入视频路径
    output_path: 输出视频路径
    target_duration: 目标时长(秒)
    """
    # 读取视频
    with VideoFileClip(input_path) as video:
        original_duration = video.duration
        print(f"原视频时长: {original_duration:.2f}秒")
        print(f"目标时长: {target_duration:.2f}秒")

        # 检查目标时长是否小于原时长
        if target_duration <= original_duration:
            raise ValueError(f"目标时长({target_duration}秒)必须大于原视频时长({original_duration:.2f}秒)")

        # 计算速度因子：原时长/目标时长，值小于1表示放慢
        speed_factor = original_duration / target_duration
        print(f"计算得到的速度因子: {speed_factor:.4f}")

        # 确保速度因子有效（大于0小于1）
        if speed_factor <= 0 or speed_factor >= 1:
            raise ValueError(f"无效的速度因子: {speed_factor:.4f}，必须在0-1之间")

        # 放慢视频速度
        adjusted_video = video.speedx(factor=speed_factor)
        print(f"调整后视频的计算时长: {original_duration / speed_factor:.2f}秒")

        # 保存调整后的视频
        adjusted_video.write_videofile(
            output_path,
            codec="libx264",
            audio_codec="aac",
            fps=video.fps
        )

        print(f"视频处理完成，保存至: {output_path}")
        print(f"实际输出视频时长应约为: {target_duration:.2f}秒")

if __name__ == "__main__":
    # 示例用法
    input_video = r"D:\Desktop\test_folder\jianying_materials_2\videos\3.mp4"
    output_video = r"D:\Desktop\test_folder\jianying_materials_2\videos\3_slow.mp4"
    target_time = 10  # 目标时长(秒)，确保大于原视频时长

    if not os.path.exists(input_video):
        print(f"错误: 找不到输入文件 {input_video}")
    else:
        try:
            slow_down_video(input_video, output_video, target_time)
        except Exception as e:
            print(f"处理失败: {str(e)}")

方法二：

from moviepy.editor import VideoFileClip
import subprocess
import os


def slow_down_video_with_ffmpeg(input_path, output_path, target_duration):
    """
    使用FFmpeg通过放慢视频速度将视频调整到指定时长
    参数:
    input_path: 输入视频路径
    output_path: 输出视频路径
    target_duration: 目标时长(秒)
    """
    with VideoFileClip(input_path) as video:
        original_duration = video.duration
        if target_duration <= original_duration:
            raise ValueError("目标时长必须大于原视频时长")
        speed_factor = original_duration / target_duration
        # FFmpeg命令，通过设置setpts参数来改变视频的pts（显示时间戳）实现放慢速度
        ffmpeg_command = [
            'ffmpeg',
            '-i', input_path,
            '-vf', f'setpts={1 / speed_factor}*PTS',
            '-af', f'atempo={speed_factor}',
            '-y',
            output_path
        ]
        try:
            subprocess.run(ffmpeg_command, check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
            print(f"视频已通过FFmpeg调整为 {target_duration} 秒，保存至: {output_path}")
        except subprocess.CalledProcessError as e:
            print(f"FFmpeg处理视频失败: {e}")


input_path = r'D:\Desktop\test_folder\jianying_materials_2\videos\3.mp4'
output_path = r'D:\Desktop\test_folder\jianying_materials_2\videos\3_slow.mp4'

slow_down_video_with_ffmpeg(input_path, output_path, 10)