获取视频第一帧作为视频封面图

最新推荐文章于 2023-05-21 14:10:33 发布

原创最新推荐文章于 2023-05-21 14:10:33 发布 · 3.7k 阅读

2 ·

CC 4.0 BY-SA版权

文章标签：

#java

java 专栏收录该内容

2 篇文章

订阅专栏

本文介绍了一种使用Java和FFmpeg库截取视频第一帧作为封面图的方法，解决了手机端上传视频时封面图可能翻转的问题，并提供了将图片转换为Base64编码的示例代码。

获取视频第一帧作为视频封面图

1.导包

		<dependency>
            <groupId>org.bytedeco</groupId>
            <artifactId>javacv</artifactId>
            <version>1.4.3</version>
        </dependency>
        
        <dependency>
            <groupId>org.bytedeco.javacpp-presets</groupId>
            <artifactId>ffmpeg-platform</artifactId>
            <version>4.0.2-1.4.3</version>
        </dependency>

2.截取视频封面代码

我这里返回的是图片的base64编码
处理了手机端上传视频截取封面图图片翻转问题

public static String fetchFrame(String videoName) {
        FFmpegFrameGrabber ff = null;
        byte[] data = null;
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        String videoPath = videoName;
        try {
            ff = new FFmpegFrameGrabber(videoPath);
            ff.start();
            int lenght = ff.getLengthInFrames();
            int i = 0;
            Frame f = null;
            while (i < lenght) {
                // 过滤前5帧，避免出现全黑的图片
                f = ff.grabFrame();
                if ((i > 5) && (f.image != null)) {
                    break;
                }
                i++;
            }
            BufferedImage bi =  new Java2DFrameConverter().getBufferedImage(f);
            String rotate = ff.getVideoMetadata("rotate");
            if (rotate != null) {
                bi = rotate(bi, Integer.parseInt(rotate));
            }
            ImageIO.write(bi, "jpg", os);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (ff != null) {
                    ff.stop();
                }
            } catch (FrameGrabber.Exception e) {
                e.printStackTrace();
            }
        }
        BASE64Encoder encoder = new BASE64Encoder();
        return "data:image/jpg;base64,"+encoder.encode(os.toByteArray());
    }
    public static BufferedImage rotate(BufferedImage src, int angel) {
        int src_width = src.getWidth(null);
        int src_height = src.getHeight(null);
        int type = src.getColorModel().getTransparency();
        Rectangle rect_des = calcRotatedSize(new Rectangle(new Dimension(src_width, src_height)), angel);
        BufferedImage bi = new BufferedImage(rect_des.width, rect_des.height, type);
        Graphics2D g2 = bi.createGraphics();
        g2.translate((rect_des.width - src_width) / 2, (rect_des.height - src_height) / 2);
        g2.rotate(Math.toRadians(angel), src_width / 2, src_height / 2);
        g2.drawImage(src, 0, 0, null);
        g2.dispose();
        return bi;
    }
    public static Rectangle calcRotatedSize(Rectangle src, int angel) {
        if (angel >= 90) {
            if(angel / 90 % 2 == 1) {
                int temp = src.height;
                src.height = src.width;
                src.width = temp;
            }
            angel = angel % 90;
        }
        double r = Math.sqrt(src.height * src.height + src.width * src.width) / 2;
        double len = 2 * Math.sin(Math.toRadians(angel) / 2) * r;
        double angel_alpha = (Math.PI - Math.toRadians(angel)) / 2;
        double angel_dalta_width = Math.atan((double) src.height / src.width);
        double angel_dalta_height = Math.atan((double) src.width / src.height);
        int len_dalta_width = (int) (len * Math.cos(Math.PI - angel_alpha - angel_dalta_width));
        int len_dalta_height = (int) (len * Math.cos(Math.PI - angel_alpha - angel_dalta_height));
        int des_width = src.width + len_dalta_width * 2;
        int des_height = src.height + len_dalta_height * 2;
        return new java.awt.Rectangle(new Dimension(des_width, des_height));
    }