ffmpeg实现电脑屏幕录像（opencv实现滤镜）和音频录取

工程地址：http://download.csdn.net/detail/qq_24038299/9690434

利用来源库ffmpeg里集成的gdigrab工具进行屏幕的获取，具体关于ffmpeg的使用方法请见其官网的说明http://ffmpeg.org/

以下是获取视频来源的部分代码：

int VideoInput::getVideoInput()
{
	AVInputFormat *ifmt;	
	pFormatCtx_Video = NULL;
	ifmt = av_find_input_format("gdigrab");
	AVDictionary *options = NULL;
	av_dict_set(&options, "framerate", framerate, NULL);            //设置录像的帧率
	if (avformat_open_input(&pFormatCtx_Video, "desktop", ifmt, &options) != 0)
	{
		printf("Couldn't open input stream.（无法打开视频输入流）\n");
		return -1;
	}
	if (avformat_find_stream_info(pFormatCtx_Video, NULL)<0)
	{
		printf("Couldn't find stream information.（无法获取视频流信息）\n");
		return -1;
	}
	if (pFormatCtx_Video->streams[0]->codec->codec_type != AVMEDIA_TYPE_VIDEO)
	{
		printf("Couldn't find video stream information.（无法获取视频流信息）\n");
		return -1;
	}
	pCodecCtx_Video = pFormatCtx_Video->streams[0]->codec;
	pCodec_Video = avcodec_find_decoder(pCodecCtx_Video->codec_id);
	if (pCodec_Video == NULL)
	{
		printf("Codec not found.（没有找到解码器）\n");
		return -1;
	}
	if (avcodec_open2(pCodecCtx_Video, pCodec_Video, NULL) < 0)
	{
		printf("Could not open codec.（无法打开解码器）\n");
		return -1;
	}
	return 0;
}

利用opencv开源库实现对ffmpeg获取到的视频进行滤镜即饱和度，锐度，色度，亮度进行调节：

void VideoInput::filterProcess(int width, int height, AVFrame *picture)		//width和height为分辨率，传入的ffmpeg的视频帧AVFrame格式为YUV格式
{
	if (brightnessswitch || contrastswitch || sharpenswitch || saturationswitch)
	{
		int size = width*height;
		unsigned char *YUVBuffer = (unsigned char *)malloc(size * 3 / 2);

		memcpy(YUVBuffer, picture->data[0], size);
		memcpy(YUVBuffer + size, picture->data[1], size / 4);
		memcpy(YUVBuffer + size * 5 / 4, picture->data[2], size / 4);
		
		cv::Mat srcyuv(height + height / 2, width, CV_8UC1, YUVBuffer);
		cv::Mat detrgb(height, width, CV_8UC1);
		cvtColor(srcyuv, detrgb, CV_YUV2BGR_YV12);
		//调用对应的滤镜的处理
		if (brightnessswitch)
		{
			brightnessProcess(width, height,&detrgb);   
		}
		if (contrastswitch) {
			contrastProcess(width, height,&detrgb);
		}
		if (sharpenswitch) {
			sharpenProcess(width, height, &detrgb);
		}
		if (saturationswitch) {
			saturationProcess(width, height,&detrgb);
		}

		cvtColor(detrgb, srcyuv, CV_BGR2YUV_YV12);		//滤镜效果处理后从RGB格式转为YUV格式
		memcpy(picture->data[0],srcyuv.data, size);
		memcpy(picture->data[1],srcyuv.data+size, size / 4);
		memcpy(picture->data[2],srcyuv.data +size * 5 / 4,size / 4);
		free(YUVBuffer);
	}
	return;
}
//亮度调节
void VideoInput::brightnessProcess(int width,int height, cv::Mat *src)
{
	cv::Mat pnewmat;
	
	pnewmat = pnewmat.zeros(src->size(),src->type());
	for (int y = 0; y < src->rows; y++)
	{
		for (int x = 0; x < src->cols; x++)
		{
			for (int c = 0; c < 3; c++)
			{
				pnewmat.at(y, x)[c] = cv::saturate_cast((src->at(y, x)[c]) + brightness);
			}
		}
	}
	cv::imshow("source", *(src));
	cv::waitKey(1);
	cv::imshow("new", pnewmat);
	cv::waitKey(1);
	pnewmat.copyTo(*(src));
}
//对比度调节
void VideoInput::contrastProcess(int width, int height,cv::Mat *src)
{
	cv::Mat pNewMat;
	
	pNewMat = pNewMat.zeros(src->size(), src->type());
	for (int y = 0; y < src->rows; y++)
	{
		for (int x = 0; x < src->cols; x++)
		{
			for (int c = 0; c < 3; c++)
			{
				pNewMat.at(y, x)[c] = cv::saturate_cast(contrast*(src->at(y, x)[c]));
			}
		}
	}
	cv::imshow("source", *(src));
	cv::waitKey(1);
	cv::imshow("new", pNewMat);
	cv::waitKey(1);
	pNewMat.copyTo(*src);
	return;
}
//饱和度调节
void VideoInput::saturationProcess(int width, int height, cv::Mat *src)
{
	IplImage ImageSrc;
	CvScalar s1;
	int i, j;

	imshow("source", *(src));
	cv::waitKey(1);
	ImageSrc = *(src);

	cvCvtColor(&ImageSrc, &ImageSrc, CV_BGR2HSV);
	for (i = 0; irows; i++) {
		for (j = 0; jcols; j++) {
			s1 = cvGet2D(&ImageSrc, i, j);
			s1.val[1] = s1.val[1] + saturation;
			cvSet2D(&ImageSrc, i, j, s1);
		}
	}
	cvCvtColor(&ImageSrc, &ImageSrc, CV_HSV2BGR);
	imshow("new", *(src));
	cv::waitKey(1);
	return;
}
//锐度调节
void VideoInput::sharpenProcess(int width, int height, cv::Mat *src)
{
	IplImage image_1;
	IplImage image_2, image_3;
	CvScalar s1, s2;
	int i, j;

	cv::Mat src3 = cv::Mat(height, width, CV_8UC3, 1);

	
	cv::Mat src2(height, width, CV_8UC1);
	//cvtColor(srcyuv, src2, CV_YUV2BGR_YV12);

	imshow("source", *(src));
	cv::waitKey(1);

	image_1 = *(src);
	src->copyTo(src2);
	image_2 = src2;
	image_3 = src3;
	if (sharpen % 2 == 0) {
		sharpen += 1;
	}
	cvSmooth(&image_2, &image_3, CV_GAUSSIAN, sharpen);

	for (i = 0; irows; i++) {
		for (j = 0; jcols; j++) {
			s1 = cvGet2D(&image_2, i, j);
			s2 = cvGet2D(&image_3, i, j);
			s1.val[0] = s1.val[0] - s2.val[0];
			s1.val[1] = s1.val[1] - s2.val[1];
			s1.val[2] = s1.val[2] - s2.val[2];
			cvSet2D(&image_2, i, j, s1);
		}
	}
	for (i = 0; irows; i++) {
		for (j = 0; jcols; j++) {
			s1 = cvGet2D(&image_1, i, j);
			s2 = cvGet2D(&image_2, i, j);
			s1.val[0] = s1.val[0] + s2.val[0];
			s1.val[1] = s1.val[1] + s2.val[1];
			s1.val[2] = s1.val[2] + s2.val[2];
			cvSet2D(&image_1, i, j, s1);
		}
	}
	imshow("new", *(src));
	cv::waitKey(1);
}

利用ffmpeg集成的dshow可以进行麦克风音频的获取，通过安装虚拟的声卡virtual audio cable 4.10来将电脑的输出的音频虚拟转接到电脑的音频输入接口，从而实现电脑声音的实时录取。以下是获取音频输入来源的部分程序：（virtual audio cable 4.10资源下载：http://download.csdn.net/detail/qq_24038299/9677547，使用时候需要将音频的输入输出均设置默认为Line 1）

int  AudioInput::getAudioInput()
{
	pFormatCtx_Audio = NULL;
	pAudioInputFmt = NULL;
	int                     AudioIndex = -1;

	//查找输入方式  
	pAudioInputFmt = av_find_input_format("dshow");
	//以Direct Show的方式打开设备，并将 输入方式 关联到格式上下文  
	//char * psDevName = dup_wchar_to_utf8(L"audio=麦克风 (Realtek High Definition Au");    //麦克风输入
	char *pDevName = "audio=Line 1 (Virtual Audio Cable)";
	avformat_open_input(&pFormatCtx_Audio, pDevName, pAudioInputFmt, NULL);    //获取输入内容的上下文

	if (avformat_find_stream_info(pFormatCtx_Audio, NULL)<0)
		return -1;

	for (int i = 0; inb_streams; i++)
	{
		if (pFormatCtx_Audio->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO)
		{
			AudioIndex = i;
			AVCodec *tmpCodec = avcodec_find_decoder(pFormatCtx_Audio->streams[i]->codec->codec_id);
			if (0 > avcodec_open2(pFormatCtx_Audio->streams[i]->codec, tmpCodec, NULL))
			{
				printf("can not find or open decoder!\n");
			}

			break;
		}
	}
	av_dump_format(pFormatCtx_Audio, 0, NULL, 0);   //打印音频相关信息
	
	return 0;
}