//------------maven配置文件---------------

org.bytedeco

javacv

0.8

/**

* 获取指定视频的帧并保存为图片至指定目录

* @param videofile 源视频文件路径

* @param framefile 截取帧的图片存放路径

* @throws Exception

*/

public static void fetchFrame(String videofile, String framefile)

throws Exception {

long start = System.currentTimeMillis();

File targetFile = new File(framefile);

FFmpegFrameGrabber ff = new FFmpegFrameGrabber(videofile);

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，依自己情况而定

f = ff.grabFrame();

if ((i > 5) && (f.image != null)) {

break;

}

i++;

}

IplImage img = f.image;

int owidth = img.width();

int oheight = img.height();

// 对截取的帧进行等比例缩放

int width = 800;

int height = (int) (((double) width / owidth) * oheight);

BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR);

bi.getGraphics().drawImage(f.image.getBufferedImage().getScaledInstance(width, height, Image.SCALE_SMOOTH),

0, 0, null);

ImageIO.write(bi, "jpg", targetFile);

// ff.flush();

ff.stop();

System.out.println(System.currentTimeMillis() - start);

}

public static void main(String[] args) {

try {

ImageUtil.fetchFrame("https://jsjoke.net/upload-1529285839603-touristappid.o6zAJswEDExvrLeuQTdnRSIz87Vo.f0fd65c07d78b8fc831c97888e4d7a55.mp4", "D:/test4.jpg");

} catch (Exception e) {

e.printStackTrace();

}

}

--------------------------------------- 解决图片旋转问题---------------------------------------

通过一段时间的搜索了解到，如果拍摄的视频中带有旋转(rotate)信息，那么截取出来的图片就会被旋转。通过查询API发现FFmpegFrameGrabber的getVideoMetadata("rotate")方法可以获取到视频的旋转信息。根据获取到的rotate信息对ff.grabImage()得到的Frame进行旋转，但是Frame并没有提供旋转接口。但有一个IpImage对象提供了旋转方法

public static void main(String[] args) {

try {

ImageUtil.fetchFrame("https://jsjoke.net/upload-1529285839603-touristappid.o6zAJswEDExvrLeuQTdnRSIz87Vo.f0fd65c07d78b8fc831c97888e4d7a55.mp4", "D:/test4.jpg");

} catch (Exception e) {

e.printStackTrace();

}

}

public static IplImage rotate(IplImage src, int rotate) {

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;

}

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.IOException;

import javax.imageio.ImageIO;

import org.bytedeco.javacpp.opencv_core;

import org.bytedeco.javacpp.opencv_core.IplImage;

import org.bytedeco.javacv.FFmpegFrameGrabber;

import org.bytedeco.javacv.Frame;

import org.bytedeco.javacv.FrameGrabber.Exception;

import org.bytedeco.javacv.Java2DFrameConverter;

import org.bytedeco.javacv.OpenCVFrameConverter;

public abstract class FrameGrabberKit {

public static void main(String[] args) throws Exception {

randomGrabberFFmpegImage("C:/Users\\Administrator\\Desktop\\VID_20171229_162251.mp4", "G:\\test", "111");

}

public static void randomGrabberFFmpegImage(String filePath, String targerFilePath, String targetFileName)

throws Exception {

FFmpegFrameGrabber ff = FFmpegFrameGrabber.createDefault(filePath);

ff.start();

String rotate =ff.getVideoMetadata("rotate");

Frame f;

int i = 0;

while (i <1) {

f =ff.grabImage();

IplImage src = null;

if(null !=rotate &&rotate.length() > 1) {

OpenCVFrameConverter.ToIplImage converter =new OpenCVFrameConverter.ToIplImage();

src =converter.convert(f);

f =converter.convert(rotate(src, Integer.valueOf(rotate)));

}

doExecuteFrame(f,targerFilePath,targetFileName);

i++;

}

ff.stop();

}

/*

* 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;

}

public static void doExecuteFrame(Frame f, String targerFilePath, String targetFileName) {

if (null ==f ||null ==f.image) {

return;

}

Java2DFrameConverter converter =new Java2DFrameConverter();

String imageMat ="jpg";

String FileName =targerFilePath + File.separator +targetFileName +"." +imageMat;

BufferedImage bi =converter.getBufferedImage(f);

System.out.println("width:" + bi.getWidth());

System.out.println("height:" + bi.getHeight());

File output =new File(FileName);

try {

ImageIO.write(bi,imageMat,output);

}catch (IOException e) {

e.printStackTrace();

}

}

}

org.bytedeco

javacv-platform

1.3.1

来源：