查询了网上很多资料，发现没有比较靠谱的实现，JavaCV的资料还是比较少的
安装依赖
<dependency>
<groupId>org.bytedeco</groupId>
<artifactId>javacv-platform</artifactId>
<version>1.5.3</version>
</dependency>
代码实现
/**
* 视频转码
*/
public static void recode() throws FrameGrabber.Exception, FrameRecorder.Exception {
String filePath = "ef568e9b96be750fba2e918b651aa70c.avi";
String ext = filePath.substring(filePath.lastIndexOf("."));
String newFilePath = filePath.replace(ext, "_recode.mp4");
FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(filePath);
grabber.start();
FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(newFilePath, grabber.getImageWidth(),
grabber.getImageHeight(), grabber.getAudioChannels());
recorder.setVideoCodec(avcodec.AV_CODEC_ID_H264);
recorder.setFormat("mp4");
recorder.setPixelFormat(avutil.AV_PIX_FMT_YUV420P);
recorder.setFrameRate(grabber.getFrameRate());
int bitrate = grabber.getVideoBitrate();
if (bitrate == 0) {
bitrate = grabber.getAudioBitrate();
}
recorder.setVideoBitrate(bitrate);
recorder.start(grabber.getFormatContext());
AVPacket packet;
long dts = 0;
while ((packet = grabber.grabPacket()) != null) {
long currentDts = packet.dts();
if (currentDts >= dts) {
recorder.recordPacket(packet);
}
dts = currentDts;
}
recorder.stop();
recorder.release();
grabber.stop();
}
