java 视频流截屏，形成缩略图

1.maven

  <!--javacv 精简版本 ffmpeg -->
        <dependency>
            <groupId>org.bytedeco</groupId>
            <artifactId>javacv</artifactId>
            <version>1.4.1</version>
        </dependency>
        <dependency>
            <groupId>org.bytedeco</groupId>
            <artifactId>javacpp</artifactId>
            <version>1.4.1</version>
        </dependency>
        <dependency>
            <groupId>org.bytedeco.javacpp-presets</groupId>
            <artifactId>opencv-platform</artifactId>
            <version>3.4.1-1.4.1</version>
        </dependency>
        <dependency>
            <groupId>org.bytedeco.javacpp-presets</groupId>
            <artifactId>ffmpeg-platform</artifactId>
            <version>3.4.2-1.4.1</version>
        </dependency>

2.截图

//使用javacv
public String cutImage(MultipartFile multipartFile,Integer number) throws IOException, ApiException {
        String picPath = StringUtils.EMPTY;
        FFmpegFrameGrabber ff = new FFmpegFrameGrabber(MultipartFileToFile(multipartFile));
        try {
            ff.start();
            int i = 0;
            int length = ff.getLengthInFrames();
            Frame frame = null;
            while (i < length) {
                frame = ff.grabFrame();
                //截取第几帧图片
                if ((i > number) && (frame.image != null)) {
                    //获取生成图片的路径
                    //执行截图并放入指定位置
                    picPath = doExecuteFrame(frame);
                    break;
                }
                i++;
            }
            ff.stop();
        } catch (FrameGrabber.Exception e) {
            e.printStackTrace();
        }
        return picPath;
    }

 /**
     * 截取缩略图
     *
     * @param f Frame
     */
    private static String doExecuteFrame(Frame f) throws IOException, ApiException {
        String imagemat = "png";
        if (null == f || null == f.image) {
            return null;
        }
        Java2DFrameConverter converter = new Java2DFrameConverter();
        BufferedImage bi = converter.getBufferedImage(f);
        ByteArrayOutputStream bs = new ByteArrayOutputStream();

        ImageOutputStream imOut = ImageIO.createImageOutputStream(bs);

        ImageIO.write(bi, "png", imOut);
        InputStream is = new ByteArrayInputStream(bs.toByteArray());

        Integer available = is.available();
        Long size = available.longValue();

        String fileName = UUID.randomUUID().toString() + ".png";
        StringBuilder stringBuilder = new StringBuilder(OssConstant.objectNamePrefix);
        MtpOssUtil.OssConfig ossConfig = new MtpOssUtil().new OssConfig(OssConstant.bucketName, OssConstant.endpoint, OssConstant.accessKeyId, OssConstant.accessKeySecret);

        String filePath = MtpOssUtil.upload(ossConfig, fileName, is, size);
        return filePath;
    }

//文件转化 
private static File MultipartFileToFile(MultipartFile multiFile) {
        // 获取文件名
        String fileName = multiFile.getOriginalFilename();
        // 获取文件后缀
        String prefix = fileName.substring(fileName.lastIndexOf("."));
        // 若需要防止生成的临时文件重复,可以在文件名后添加随机码

        try {
            File file = File.createTempFile(fileName, prefix);
            multiFile.transferTo(file);
            return file;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }