Java 获取视频缩略图

简述

项目中需要获取视频的缩略图，并发和性能要求不够高，ffmpeg，javacv 配置比较麻烦，找了一个基本满足需求，比较轻量的工具 jcodec 。

示例

依赖：

<dependency>
    <groupId>org.jcodecgroupId>
    <artifactId>jcodecartifactId>
    <version>0.2.3version>
dependency>
<dependency>
    <groupId>org.jcodecgroupId>
    <artifactId>jcodec-javaseartifactId>
    <version>0.2.3version>
dependency>

代码：

import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;

import org.jcodec.api.FrameGrab;
import org.jcodec.api.JCodecException;
import org.jcodec.common.model.Picture;
import org.jcodec.scale.AWTUtil;

public final class VideoUtils {

    private static final int THUMB_FRAME = 5;

    private VideoUtils() { }

    /**
     * 获取视频指定帧
     * @author sunk
     */
    public static BufferedImage getFrame (File file, int frameNumber)
            throws IOException, JCodecException {

        Picture picture = FrameGrab.getFrameFromFile(file, frameNumber);
        return AWTUtil.toBufferedImage(picture);
    }

    /**
     * 获取缩略图
     * @author sunk
     */
    public static ByteArrayOutputStream getThumbnail(File file,
            int limit) throws IOException, JCodecException {

        BufferedImage frameBi = getFrame(file, THUMB_FRAME);
        return ImageUtils.getThumbnail(frameBi, limit);
    }

    /**
     * 获取缩略图
     * @author sunk
     */
    public static ByteArrayOutputStream getThumbnail(File file)
            throws IOException, JCodecException {

        BufferedImage frameBi = getFrame(file, THUMB_FRAME);
        return ImageUtils.getThumbnail(frameBi);
    }
}

import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;

public final class ImageUtils {

    //缩略图默认长宽限制
    private static final int THUMBNAIL_DEFAULT_LIMIT = 400;

    private ImageUtils() { }

    /**
     * 根据长宽值缩放
     * @author sunk
     */
    public static BufferedImage scaleByWh(BufferedImage source, int width, int height) {
        return getBufferedImageLocal(source.getScaledInstance(width, height, Image.SCALE_SMOOTH));
    }

    /**
     * 根据长宽限制缩放
     * 
 限制较大的一边
     * @author sunk
     */
    public static BufferedImage scaleByWhLimit(BufferedImage source, int limit) {
        int scaleW = -1;
        int scaleH = -1;

        if (source.getWidth() > source.getHeight()) {
            scaleW = limit;
        } else {
            scaleH = limit;
        }
        return scaleByWh(source, scaleW, scaleH);
    }

    /**
     * 根据比例缩放
     * @author sunk
     */
    public static BufferedImage scaleByRatio(BufferedImage source, double ratio) {

        int w = (int) (source.getWidth() * ratio);
        int h = (int) (source.getHeight() * ratio);
        return scaleByWh(source, w, h);
    }

    /**
     * 将 Image 转为 BufferedImage
     * @author sunk
     */
    public static BufferedImage getBufferedImage(Image img) {
        if (img instanceof BufferedImage) {
            return (BufferedImage) img;
        }

        BufferedImage bufImage = new BufferedImage(img.getWidth(null),
                img.getHeight(null), BufferedImage.TYPE_INT_RGB);

        Graphics2D g2d = bufImage.createGraphics();
        g2d.drawImage(img, 0, 0, null);
        g2d.dispose();

        return bufImage;
    }

    /**
     * 将 Image 转为 BufferedImage
     * @author sunk
     */
    public static BufferedImage getBufferedImageLocal(Image img) {
        if (img instanceof BufferedImage) {
            return (BufferedImage) img;
        }

        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice gd = ge.getDefaultScreenDevice();
        GraphicsConfiguration gc = gd.getDefaultConfiguration();
        BufferedImage bufImage = gc.createCompatibleImage(img.getWidth(null),
                img.getHeight(null));

        Graphics2D g2d = bufImage.createGraphics();
        g2d.drawImage(img, 0, 0, null);
        g2d.dispose();

        return bufImage;
    }

    /**
     * 获取缩略图
     * @author sunk
     */
    public static ByteArrayOutputStream getThumbnail(BufferedImage sourceBi,
            int limit) throws IOException {

        //缩放
        BufferedImage scaledBi = scaleByWhLimit(sourceBi, limit);

        //压缩
        ByteArrayOutputStream compressedOs = new ByteArrayOutputStream();
        ImageWriter jpgWriter = ImageIO.getImageWritersByFormatName("jpg").next();
        ImageWriteParam jpgWriteParam = jpgWriter.getDefaultWriteParam();
        jpgWriteParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
        jpgWriteParam.setCompressionQuality(0.5f);

        jpgWriter.setOutput(ImageIO.createImageOutputStream(compressedOs));
        jpgWriter.write(null, new IIOImage(scaledBi, null, null), jpgWriteParam);

        return compressedOs;
    }

    /**
     * 获取缩略图
     * @author sunk
     */
    public static ByteArrayOutputStream getThumbnail(BufferedImage sourceBi)
            throws IOException {
        return getThumbnail(sourceBi, THUMBNAIL_DEFAULT_LIMIT);
    }

    /**
     * 获取缩略图
     * @author sunk
     */
    public static ByteArrayOutputStream getThumbnail(File sourceFile, int limit)
            throws IOException {

        return getThumbnail(ImageIO.read(sourceFile), limit);
    }

    /**
     * 获取缩略图
     * @author sunk
     */
    public static ByteArrayOutputStream getThumbnail(File source)
            throws IOException {

        return getThumbnail(ImageIO.read(source));
    }
}

参考

1.JCodec
2.JCodec main repo