<dependency>
    <groupId>org.bytedeco</groupId>
    <artifactId>javacv</artifactId>
    <version>1.5.1</version>
</dependency>
<!-- 視頻處理包 -->
<dependency>
    <groupId>org.bytedeco</groupId>
    <artifactId>ffmpeg-platform</artifactId>
    <version>4.1.3-1.5.1</version>
</dependency>

package com.test.demo;
import org.bytedeco.ffmpeg.global.avcodec;
import org.bytedeco.ffmpeg.global.avutil;
import org.bytedeco.javacv.FFmpegFrameGrabber;
import org.bytedeco.javacv.FFmpegFrameRecorder;
import org.bytedeco.javacv.Frame;
import org.bytedeco.javacv.FrameGrabber;
import org.bytedeco.javacv.FrameRecorder;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.ArrayList;
import java.util.List;

import static org.bytedeco.ffmpeg.global.avutil.AV_LOG_ERROR;


@SpringBootTest
public class MP4Test {

    public static void main(String[] args) throws FrameRecorder.Exception, FrameGrabber.Exception {
        List<String> file = new ArrayList<>();
        // 添加需要合并的mp4文件
        file.add("C:\Users\Administrator\Desktop\1\source\1.mp4");
        file.add("C:\Users\Administrator\Desktop\1\source\2.mp4");
        long start = System.currentTimeMillis();
        // 合并
        videoMerge(file, "C:\Users\Administrator\Desktop\1\1\5.mp4");
        // 統計耗時
        System.out.println("耗時" + (System.currentTimeMillis() - start) + "毫秒");
    }

    /**
     * 多個視頻的合并
     *
     * @param videoList 地址集合
     * @param output    合并后的視頻輸出地址
     */
    public static void videoMerge(List<String> videoList, String output) throws FrameRecorder.Exception, FrameGrabber.Exception {
        // 幀抓取器 以第一個視頻為藍本開始抓取
        FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(videoList.get(0));
        // 載入
        grabber.start();
        // 配置幀解碼器
        FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(output, grabber.getImageWidth(),
                grabber.getImageHeight(), 0);
        // 視頻編解碼器
        recorder.setVideoCodec(avcodec.AV_CODEC_ID_H264);
        recorder.setAudioCodec(avcodec.AV_CODEC_ID_AAC); // 設置音頻編解碼器
        // 單通道
        recorder.setAudioChannels(1);
        recorder.setInterleaved(true);
        // 輸出流封裝格式
        recorder.setFormat("mp4");
        // 視頻幀率
        recorder.setFrameRate(grabber.getFrameRate());
        // 設置日志輸出（error）
        avutil.av_log_set_level(AV_LOG_ERROR);
        // 設置分辨率格式 yuv420p
        recorder.setPixelFormat(avutil.AV_PIX_FMT_YUV420P);
        // 設置視頻比特率
        recorder.setVideoBitrate(grabber.getVideoBitrate());
        // 音頻比特率
        recorder.setAudioBitrate(grabber.getAudioBitrate()); // 設置音頻比特率
        // 開始編碼
        recorder.start();

        // 循環(huán)設置
        for (String videoPath : videoList) {
            try (FFmpegFrameGrabber grabberTemp = new FFmpegFrameGrabber(videoPath)) {
                grabberTemp.start();
                //設置幀
                Frame frame;
                while ((frame = grabberTemp.grabFrame()) != null) {
                    recorder.record(frame);
                }

                // 處理音頻幀
                Frame audioFrame;
                while ((audioFrame = grabberTemp.grabSamples()) != null) {
                    recorder.record(audioFrame);
                }
            } catch (FrameGrabber.Exception e) {
                System.err.println("Error grabbing frames from video: " + videoPath);
                e.printStackTrace();
            }
        }
        // 關閉幀編解碼器
        recorder.close();
        grabber.close();
    }
}