ffmpeg java 视频工具类代码，实现拆分合并

在Java中使用FFmpeg实现视频的拆分和合并，通常需要借助FFmpeg的命令行工具，并通过Java的ProcessBuilder类来执行这些命令。以下是一个简单的Java工具类示例，展示了如何使用FFmpeg命令进行视频的拆分和合并：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class VideoUtil {

    // 执行FFmpeg命令并获取输出
    public static String executeCommand(String... cmd) throws IOException {
        ProcessBuilder processBuilder = new ProcessBuilder(cmd);
        processBuilder.redirectErrorStream(true);
        Process process = processBuilder.start();
        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
        StringBuilder output = new StringBuilder();
        String line;
        while ((line = reader.readLine()) != null) {
            output.append(line).append("\n");
        }
        int exitCode = process.waitFor();
        if (exitCode != 0) {
            throw new RuntimeException("Command execution failed with exit code " + exitCode + ":\n" + output);
        }
        return output.toString();
    }

    // 拆分视频
    public static void splitVideo(String inputPath, String outputPath, int startTime, int endTime) {
        String[] cmd = {
            "ffmpeg",
            "-i", inputPath,
            "-ss", String.valueOf(startTime),
            "-to", String.valueOf(endTime),
            "-c", "copy",
            outputPath
        };
        try {
            String result = executeCommand(cmd);
            System.out.println("Video split result: " + result);
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }
    }

    // 合并视频
    public static void mergeVideo(String[] inputFiles, String outputFilePath) {
        StringBuilder cmd = new StringBuilder("ffmpeg -f concat -safe 0 -i ");
        for (int i = 0; i < inputFiles.length; i++) {
            cmd.append(" -i ").append(inputFiles[i]);
        }
        cmd.append(" -c copy ").append(outputFilePath);
        String[] cmdArray = cmd.toString().split(" ");
        try {
            String result = executeCommand(cmdArray);
            System.out.println("Video merge result: " + result);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

使用方法：
- 调用`splitVideo`方法来拆分视频，指定输入视频路径、输出视频路径以及拆分的开始时间和结束时间。
- 调用`mergeVideo`方法来合并视频，传入一个包含所有要合并视频文件路径的字符串数组，以及最终输出的视频路径。

示例使用代码：

public class Main {
    public static void main(String[] args) {
        // 拆分视频示例
        VideoUtil.splitVideo("input.mp4", "output.mp4", 0, 10);

        // 合并视频示例
        String[] videoFiles = {"video1.mp4", "video2.mp4"};
        VideoUtil.mergeVideo(videoFiles, "mergedVideo.mp4");
    }
}