从视频中提取一张图片

最新推荐文章于 2025-09-13 09:57:01 发布

原创最新推荐文章于 2025-09-13 09:57:01 发布 · 545 阅读

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#opencv

这段代码展示了如何利用FFmpegFrameGrabber从视频文件中抓取关键帧，并通过OpenCV进行图像旋转。首先，创建FFmpegFrameGrabber实例并启动，然后抓取关键帧。如果需要，根据元数据旋转图像。之后，将处理后的帧转换为BufferedImage并保存到指定目录。如果需要，还可以按比例压缩图像。最后返回保存的图片路径。

public static String randomGrabberFFmpegImage(String videoFilePath, String targetDirPath, String imageFileName){
        try {
            FFmpegFrameGrabber frameGrabber = new FFmpegFrameGrabber(videoFilePath);
            frameGrabber.start();
            Frame keyFrame = frameGrabber.grabKeyFrame();

            // 看一下是否需要旋转
            Frame rotateFrame = rotateFrame(frameGrabber, keyFrame);

            Java2DFrameConverter java2DFrameConverter = new Java2DFrameConverter();
            BufferedImage bufferedImage = java2DFrameConverter.convert(rotateFrame==null ? keyFrame : rotateFrame);
            frameGrabber.stop();

            File file = writeFile(bufferedImage, imageFileName,targetDirPath);
            if (file != null && file.exists()) {
                return file.getAbsolutePath();
            }
        } catch (Exception e) {
            log.error("抓图发生错误", e);
        }
        return null;
    }

    private static Frame rotateFrame(FFmpegFrameGrabber frameGrabber, Frame frame) {
        //获取旋转角度信息（90度）
        String rotate = frameGrabber.getVideoMetadata("rotate");

        if(null != rotate && rotate.length() > 1) {
            try {
                int angle = Integer.parseInt(rotate);
                log.info("抓图片开始，旋转角度:{}", angle);

                OpenCVFrameConverter.ToIplImage converter = new OpenCVFrameConverter.ToIplImage();
                IplImage src = converter.convert(frame);
                return converter.convert(rotate(src, angle));
            }
            catch (Exception e) {
                log.error("旋转图片发生错误", e);
            }
        }

        return null;
    }

    private static File writeFile(BufferedImage bufferedImage, String imageFileName, String targetDirPath) {
        if (null == bufferedImage) {
            return null;
        }

        String imageMat = getImageMat();
        String fileName = imageFileName + "."  + imageMat;
        String filePath = targetDirPath + File.separator + fileName;

        log.info("输出图片：{}", filePath);
        File output = new File(filePath);
        try {
            if (isCompressImage()) {
                BufferedImage thumb = thumbnail(bufferedImage, 50);
                ImageIO.write(thumb, imageMat, output);
            }
            else{
                ImageIO.write(bufferedImage, imageMat, output);
            }
        }catch (IOException e) {
            log.error("压缩输出图片发生错误", e);
        }
        return output;
    }

    /*
     * 旋转角度的
     */
    public static IplImage rotate(IplImage src, int angle) {
        IplImage img = IplImage.create(src.height(), src.width(), src.depth(), src.nChannels());
        opencv_core.cvTranspose(src, img);
        opencv_core.cvFlip(img, img, angle);
        return img;
    }

    /**
     * 按照固定宽高原图压缩
     * @param bufferedImage 图像源
     * @param scale 缩放比例
     * @return
     */
    public static BufferedImage thumbnail(BufferedImage bufferedImage, int scale) {
        if (scale > 100) {
            scale = 100;
        }
        if (scale < 1) {
            scale = 1;
        }
        int oriWidth = bufferedImage.getWidth();
        int oriHeight = bufferedImage.getHeight();
        int width = oriWidth * scale / 100;
        int height = oriHeight * scale / 100;

        log.info("压缩图片：原始大小{}*{}，新尺寸：{}*{}", oriWidth, oriHeight, width, height);

        Image image = bufferedImage.getScaledInstance(width, height, Image.SCALE_SMOOTH);
        BufferedImage newImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics graphics = newImage.getGraphics();
        graphics.setColor(Color.RED);
        // 绘制处理后的图
        graphics.drawImage(image, 0, 0, null);
        graphics.dispose();

        return newImage;
    }