为什么写这篇文章？

  起因是项目中会用到rtsp流，用于分析视频，和语音口令，还有就是控制摄像头和做监控时候做云端存储功能。在网上找了一大圈发现这方面资料很少，资料中大部分人还是FFmpeg的安装程序加代码的方式实现。
  其实JAVACV和OPENCV是非常强大的。当然我了解的也不多（因为源码没有什么注释！！理解起来很困难）。这篇文章最主要是针对于目前GPT和通义前问中提供的代码进行纠错和改正（特别是从rtsp中只取出音频）。
  部分代码是他人提供，所以看起来会有差异，不过我会进行说明。

pom

 	org.bytedeco 	javacv-platform 	1.5.9       

取出视频保存为mp4代码

    /**      * 拉取指定时长的视频-保存为mp4      *      * @param rtspUrl    流地址      * @param duration   时长（秒）（TimeUnit Seconds）      * @param outputFile 输出位置      */     public static void videoPuller(String rtspUrl, int duration, String outputFile) {         // 创建抓取器         FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(rtspUrl);         try {             grabber.start();             // 创建录制器-设置的文件保存位置以及视频画面的宽度和高度             FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(outputFile, grabber.getImageWidth(), grabber.getImageHeight());             recorder.setVideoCodec(avcodec.AV_CODEC_ID_H264); // 设置视频编解码器             recorder.setFormat("mp4"); // 设置视频输出格式              // 设置音频相关参数             recorder.setAudioCodec(avcodec.AV_CODEC_ID_AAC);             //这里直接写2以及后续写固定值也可以，当然我们可以从grabber对象中get出来             //grabber.getAudioChannels();             // recorder.setAudioChannels(grabber.getAudioChannels());             recorder.setAudioChannels(2);             //grabber.getSampleRate();             recorder.setSampleRate(44100);              //grabber.getAudioBitrate();             recorder.setAudioBitrate(192000);             recorder.start();              Frame frame;             long startTime = System.currentTimeMillis();             long endTime = startTime + (duration * 1000);              while ((frame = grabber.grabFrame()) != null && System.currentTimeMillis() <= endTime) {                 recorder.record(frame);             }             recorder.stop();             grabber.stop();             recorder.close();             grabber.close();         } catch (FrameGrabber.Exception | FrameRecorder.Exception e) {             e.printStackTrace();         }     }      public static void main(String[] args) throws IOException { 		videoPuller("rtsp流地址",60, "D:\\va\\a.mp4");     } 

只保存音频

import org.bytedeco.ffmpeg.global.avcodec; import org.bytedeco.javacv.*;  /**  * @author by Guoshun  * @version 1.0.0  * @description 提取音频测试  * @date 2024/2/26 16:57  */  public class AudioExtractor {     public static void extractAudioFromRtsp(String rtspUrl, String outputPath, int maxDurationSeconds) throws Exception {         FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(rtspUrl);         grabber.start();          //1.从视频流中取出读取到的参数         int audioChannels = grabber.getAudioChannels();//音频通道         int sampleRate = grabber.getSampleRate();         int audioBitrate = grabber.getAudioBitrate();          //创建recorder对象，设置编码器和解码器         //这里也是所有AI都回答错误的地方         //通义和GPT会回答为这样         //FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(outputPath, audioChannels, sampleRate);         //上面这种错误传参方式导致，audioChannels变为为宽，sampleRate为高         FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(outputPath, audioChannels);         recorder.setSampleRate(sampleRate);         recorder.setAudioBitrate(audioBitrate);         recorder.setAudioCodec(avcodec.AV_CODEC_ID_PCM_S16LE); // 使用PCM 16位小端模式编码         recorder.start();          long startTime = System.currentTimeMillis();         Frame frame;         while ((frame = grabber.grabSamples()) != null && (System.currentTimeMillis() - startTime) / 1000 < maxDurationSeconds) {             recorder.record(frame, 0);         }          recorder.stop();         recorder.release();         grabber.stop();         grabber.release();     }      public static void main(String[] args) {         try {             extractAudioFromRtsp("rtsp://admin:12345qaz@192.168.20.164:554", "D:\\va\\audio.wav", 60);         } catch (Exception e) {             e.printStackTrace();         }     } } 

完整代码，并行执行

import org.bytedeco.ffmpeg.global.avcodec; import org.bytedeco.javacv.*; import org.bytedeco.opencv.opencv_core.Mat;  import javax.validation.constraints.NotNull;  import java.util.concurrent.CompletableFuture; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors;  import static org.bytedeco.opencv.global.opencv_imgcodecs.imwrite;  /**  * @author by Guoshun  * @version 1.0.0  * @description RTSP流处理  * 流地址格式 rtsp://账户:密码@ip地址  * @date 2024/2/27 10:21  */ public class RtspUtils {      /**      * 判断流地址是否在线      * @param rtspUrl 流地址      * @return      */     public static Boolean isOnline(String rtspUrl) {         FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(rtspUrl);         try {             grabber.setTimeout(3000);             grabber.start();             return true;         } catch (FrameGrabber.Exception e) {             e.printStackTrace();         } finally {             if (grabber != null) {                 close(grabber);             }         }         return false;     }      /**      * 关闭grabber      *      * @param grabber      * @return      */     private static boolean close(@NotNull FFmpegFrameGrabber grabber) {         try {             grabber.close();             return true;         } catch (FrameGrabber.Exception e) {             e.printStackTrace();         }         return false;     }      /**      * 拉取指定时长的视频-保存为mp4      * @param rtspUrl    流地址      * @param duration   时长（秒）（TimeUnit Seconds）      * @param outputFile 输出位置      */     public static void videoPuller(String rtspUrl, int duration, String outputFile) {         // 创建抓取器         FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(rtspUrl);         try {             grabber.start();             // 创建录制器             FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(outputFile, grabber.getImageWidth(), grabber.getImageHeight());             recorder.setVideoCodec(avcodec.AV_CODEC_ID_H264); // 设置视频编解码器             recorder.setFormat("mp4"); // 设置视频输出格式             // 设置音频相关参数             recorder.setAudioChannels(2);             recorder.setAudioCodec(avcodec.AV_CODEC_ID_AAC);             recorder.setSampleRate(44100);             recorder.setAudioBitrate(192000);             recorder.start();             Frame frame;             long startTime = System.currentTimeMillis();             long endTime = startTime + (duration * 1000);             while ((frame = grabber.grabFrame()) != null && System.currentTimeMillis() <= endTime) {                 recorder.record(frame);             }             recorder.stop();             grabber.stop();             recorder.close();             grabber.close();         } catch (FrameGrabber.Exception | FrameRecorder.Exception e) {             e.printStackTrace();         }     }      /**      * 提取音频      *      * @param rtspUrl      * @param outputPath      * @param maxDurationSeconds      */     public static void extractAudioFromRtsp(String rtspUrl, String outputPath, int maxDurationSeconds) {         try(             FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(rtspUrl);             FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(outputPath, 0,0)         ){             grabber.setOption("map", "0:a:0");             grabber.start();             //1.从视频流中取出读取到的参数             int audioChannels = grabber.getAudioChannels();//音频通道             int sampleRate = grabber.getSampleRate();             int audioBitrate = grabber.getAudioBitrate();             //创建recorder对象，设置编码器和解码器             recorder.setAudioChannels(audioChannels);             recorder.setSampleRate(sampleRate);             recorder.setAudioBitrate(audioBitrate);             recorder.setAudioCodec(avcodec.AV_CODEC_ID_PCM_S16LE); // 使用PCM 16位小端模式编码             recorder.start();             long startTime = System.currentTimeMillis();             Frame frame;             while ((frame = grabber.grabSamples()) != null && (System.currentTimeMillis() - startTime) / 1000 < maxDurationSeconds) {                 recorder.record(frame, 0);             }             recorder.stop();             recorder.release();             grabber.stop();             grabber.release();         }catch (FrameGrabber.Exception | FrameRecorder.Exception e){             e.printStackTrace();         }     }      /**      * 保存图片      * @param rtspUrl      * @param outputDir      * @param maxDurationSeconds 时长范围      */     public static void savePicture(String rtspUrl, String outputDir, int maxDurationSeconds) {         try(             FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(rtspUrl);             OpenCVFrameConverter.ToMat converter = new OpenCVFrameConverter.ToMat()         ){             grabber.start();             long startTime = System.currentTimeMillis();             Frame frame;             int i = 0;             while ((frame = grabber.grab()) != null && (System.currentTimeMillis() - startTime) / 1000 < maxDurationSeconds) {                 // 将Frame转换为OpenCV Mat                 Mat mat = converter.convert(frame);                 if (mat != null && i % 100 == 0) {                     // 保存帧到磁盘                     //String fileName = "frame_" + i + ".jpg";                     //imwrite(outputDir + fileName, mat);                     imwrite(outputDir + "frame_" + i + ".jpg", mat);                 }                 i++;             }         } catch (FrameGrabber.Exception e) {             e.printStackTrace();         }     }      private static String DEFAULT_RTSP_URL = "rtsp://账户:密码@ip地址";      public static void main(String[] args) throws Exception {          ExecutorService executor = Executors.newFixedThreadPool(4); // 创建线程池          CompletableFuture future1 = CompletableFuture.runAsync(() -> videoPuller(DEFAULT_RTSP_URL, 60, "D:\\va\\a.mp4"), executor);          CompletableFuture future2 = CompletableFuture.runAsync(() -> savePicture(DEFAULT_RTSP_URL, "D:\\va\\", 60), executor);          CompletableFuture future3 = CompletableFuture.runAsync(() ->                 extractAudioFromRtsp(DEFAULT_RTSP_URL, "D:\\va\\audio.wav", 60), executor);          CompletableFuture.allOf(future1, future2, future3).thenRun(() -> System.out.println("所有任务都已完成"));          // 在应用结束前关闭线程池         CompletableFuture.supplyAsync(() -> {                     return true;                 }, executor)                 .thenAccept((v) -> executor.shutdown());     }    }