ffmpeg实现录屏+录音

1、概述

最简单的基于FFmpeg的***Device例子（屏幕录制+声音采集），视频采用mpeg4编码，音频采用aac编码，并生成mp4文件，其中fifo是此程序的关键，此程序只是一个demo很多优化都没做，仅供参考。

2、代码

<pre name="code" class="cpp">/**
 *最简单的基于FFmpeg的***Device例子（屏幕录制+声音采集），视频采用mpeg4编码，音频采用aac编码，并生成mp4文件
 *缪国凯 MK
 *821486004@qq.com
 */

#include "stdafx.h"

#ifdef	__cplusplus
extern "C"
{
#endif
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include "libavdevice/avdevice.h"
#include "libavutil/audio_fifo.h"

#pragma comment(lib, "avcodec.lib")
#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "avdevice.lib")
#pragma comment(lib, "avfilter.lib")

//#pragma comment(lib, "avfilter.lib")
//#pragma comment(lib, "postproc.lib")
//#pragma comment(lib, "swresample.lib")
#pragma comment(lib, "swscale.lib")
#ifdef __cplusplus
};
#endif

***FormatContext	*pFormatCtx_Video = NULL, *pFormatCtx_Audio = NULL, *pFormatCtx_Out = NULL;
***CodecContext	*pCodecCtx_Video;
***Codec			*pCodec_Video;
***FifoBuffer	*fifo_video = NULL;
***AudioFifo		*fifo_audio = NULL;
int VideoIndex, AudioIndex;

CRITICAL_SECTION AudioSection, VideoSection;

SwsContext *img_convert_ctx;
int frame_size = 0;

uint8_t *picture_buf = NULL, *frame_buf = NULL;

bool bCap = true;

DWORD WINAPI ScreenCapThreadProc( LPVOID lpParam );
DWORD WINAPI AudioCapThreadProc( LPVOID lpParam );

int OpenVideoCapture()
{
	***InputFormat *ifmt=av_find_input_format("gdigrab");
	//这里可以加参数打开，例如可以指定采集帧率
	***Dictionary *options = NULL;
	av_dict_set(&options, "framerate", "15", NULL);
	//av_dict_set(&options,"offset_x","20",0);
	//The distance from the top edge of the screen or desktop
	//av_dict_set(&options,"offset_y","40",0);
	//Video frame size. The default is to capture the full screen
	//av_dict_set(&options,"video_size","320x240",0);
	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 != ***MEDIA_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;
	}

	

	img_convert_ctx = sws_getContext(pCodecCtx_Video->width, pCodecCtx_Video->height, pCodecCtx_Video->pix_fmt, 
		pCodecCtx_Video->width, pCodecCtx_Video->height, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL); 

	frame_size = avpicture_get_size(pCodecCtx_Video->pix_fmt, pCodecCtx_Video->width, pCodecCtx_Video->height);
	//申请30帧缓存
	fifo_video = av_fifo_alloc(30 * avpicture_get_size(***_PIX_FMT_YUV420P, pCodecCtx_Video->width, pCodecCtx_Video->height));

	return 0;
}

static char *dup_wchar_to_utf8(wchar_t *w)
{
	char *s = NULL;
	int l = WideCharToMultiByte(CP_UTF8, 0, w, -1, 0, 0, 0, 0);
	s = (char *) av_malloc(l);
	if (s)
		WideCharToMultiByte(CP_UTF8, 0, w, -1, s, l, 0, 0);
	return s;
}

int OpenAudioCapture()
{
	//查找输入方式
	***InputFormat *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");

	if (avformat_open_input(&pFormatCtx_Audio, psDevName, pAudioInputFmt,NULL) < 0)
	{
		printf("Couldn't open input stream.（无法打开音频输入流）\n");
		return -1;
	}

	if(avformat_find_stream_info(pFormatCtx_Audio,NULL)<0)  
		return -1; 
	
	if(pFormatCtx_Audio->streams[0]->codec->codec_type != ***MEDIA_TYPE_AUDIO)
	{
		printf("Couldn't find video stream information.（无法获取音频流信息）\n");
		return -1;
	}

	***Codec *tmpCodec = avcodec_find_decoder(pFormatCtx_Audio->streams[0]->codec->codec_id);
	if(0 > avcodec_open2(pFormatCtx_Audio->streams[0]->codec, tmpCodec, NULL))
	{
		printf("can not find or open audio decoder!\n");
	}

	

	return 0;
}

int OpenOutPut()
{
	***Stream *pVideoStream = NULL, *pAudioStream = NULL;
	const char *outFileName = "test.mp4";
	avformat_alloc_output_context2(&pFormatCtx_Out, NULL, NULL, outFileName);

	if (pFormatCtx_Video->streams[0]->codec->codec_type == ***MEDIA_TYPE_VIDEO)
	{
		***CodecContext *videoCodecCtx;
		VideoIndex = 0;
		pVideoStream = avformat_new_stream(pFormatCtx_Out, NULL);

		if (!pVideoStream)
		{
			printf("can not new stream for output!\n");
			return -1;
		}

		//set codec context param
		pVideoStream->codec->codec = avcodec_find_encoder(***_CODEC_ID_MPEG4);
		pVideoStream->codec->height = pFormatCtx_Video->streams[0]->codec->height;
		pVideoStream->codec->width = pFormatCtx_Video->streams[0]->codec->width;
		
		pVideoStream->codec->time_base = pFormatCtx_Video->streams[0]->codec->time_base;
		pVideoStream->codec->sample_aspect_ratio = pFormatCtx_Video->streams[0]->codec->sample_aspect_ratio;
		// take first format from list of supported formats
		pVideoStream->codec->pix_fmt = pFormatCtx_Out->streams[VideoIndex]->codec->codec->pix_fmts[0];

		//open encoder
		if (!pVideoStream->codec->codec)
		{
			printf("can not find the encoder!\n");
			return -1;
		}

		if (pFormatCtx_Out->oformat->flags & ***FMT_GLOBALHEADER)
			pVideoStream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;

		if ((avcodec_open2(pVideoStream->codec, pVideoStream->codec->codec, NULL)) < 0)
		{
			printf("can not open the encoder\n");
			return -1;
		}
	}

	if(pFormatCtx_Audio->streams[0]->codec->codec_type == ***MEDIA_TYPE_AUDIO)
	{
		***CodecContext *pOutputCodecCtx;
		AudioIndex = 1;
		pAudioStream = avformat_new_stream(pFormatCtx_Out, NULL);

		pAudioStream->codec->codec = avcodec_find_encoder(pFormatCtx_Out->oformat->audio_codec);

		pOutputCodecCtx = pAudioStream->codec;

		pOutputCodecCtx->sample_rate = pFormatCtx_Audio->streams[0]->codec->sample_rate;
		pOutputCodecCtx->channel_layout = pFormatCtx_Out->streams[0]->codec->channel_layout;
		pOutputCodecCtx->channels = av_get_channel_layout_nb_channels(pAudioStream->codec->channel_layout);
		if(pOutputCodecCtx->channel_layout == 0)
		{
			pOutputCodecCtx->channel_layout = ***_CH_LAYOUT_STEREO;
			pOutputCodecCtx->channels = av_get_channel_layout_nb_channels(pOutputCodecCtx->channel_layout);

		}
		pOutputCodecCtx->sample_fmt = pAudioStream->codec->codec->sample_fmts[0];
		***Rational time_base={1, pAudioStream->codec->sample_rate};
		pAudioStream->time_base = time_base;
		//audioCodecCtx->time_base = time_base;

		pOutputCodecCtx->codec_tag = 0;  
		if (pFormatCtx_Out->oformat->flags & ***FMT_GLOBALHEADER)  
			pOutputCodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;

		if (avcodec_open2(pOutputCodecCtx, pOutputCodecCtx->codec, 0) < 0)
		{
			//编码器打开失败，退出程序
			return -1;
		}
	}

	if (!(pFormatCtx_Out->oformat->flags & ***FMT_NOFILE))
	{
		if(avio_open(&pFormatCtx_Out->pb, outFileName, ***IO_FLAG_WRITE) < 0)
		{
			printf("can not open output file handle!\n");
			return -1;
		}
	}

	if(avformat_write_header(pFormatCtx_Out, NULL) < 0)
	{
		printf("can not write the header of the output file!\n");
		return -1;
	}

	return 0;
}

int _tmain(int argc, _TCHAR* argv[])
{
	av_register_all();
	avdevice_register_all();
	if (OpenVideoCapture() < 0)
	{
		return -1;
	}
	if (OpenAudioCapture() < 0)
	{
		return -1;
	}
	if (OpenOutPut() < 0)
	{
		return -1;
	}
	
	InitializeCriticalSection(&VideoSection);
	InitializeCriticalSection(&AudioSection);

	***Frame *picture = av_frame_alloc();
	int size = avpicture_get_size(pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt, 
		pFormatCtx_Out->streams[VideoIndex]->codec->width, pFormatCtx_Out->streams[VideoIndex]->codec->height);
	picture_buf = new uint8_t[size];

	avpicture_fill((***Picture *)picture, picture_buf, 
		pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt, 
		pFormatCtx_Out->streams[VideoIndex]->codec->width, 
		pFormatCtx_Out->streams[VideoIndex]->codec->height);

	//star cap screen thread
	CreateThread( NULL, 0, ScreenCapThreadProc, 0, 0, NULL);
	//star cap audio thread
	CreateThread( NULL, 0, AudioCapThreadProc, 0, 0, NULL);
	int64_t cur_pts_v=0,cur_pts_a=0;
	int VideoFrameIndex = 0, AudioFrameIndex = 0;

	while(1)
	{
		if (_kbhit() != 0 && bCap)
		{
			bCap = false;
			Sleep(2000);//简单的用sleep等待采集线程关闭
		}
		if (fifo_audio && fifo_video)
		{
			int sizeAudio = av_audio_fifo_size(fifo_audio);
			int sizeVideo = av_fifo_size(fifo_video);
			//缓存数据写完就结束循环
			if (av_audio_fifo_size(fifo_audio) <= pFormatCtx_Out->streams[AudioIndex]->codec->frame_size && 
				av_fifo_size(fifo_video) <= frame_size && !bCap)
			{
				break;
			}
		}

		if(av_compare_ts(cur_pts_v, pFormatCtx_Out->streams[VideoIndex]->time_base, 
			cur_pts_a,pFormatCtx_Out->streams[AudioIndex]->time_base) <= 0)
		{
			//read data from fifo
			if (av_fifo_size(fifo_video) < frame_size && !bCap)
			{
				cur_pts_v = 0x7fffffffffffffff;
			}
			if(av_fifo_size(fifo_video) >= size)
			{
				EnterCriticalSection(&VideoSection);
				av_fifo_generic_read(fifo_video, picture_buf, size, NULL);
				LeaveCriticalSection(&VideoSection);
				
				avpicture_fill((***Picture *)picture, picture_buf, 
					pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt, 
					pFormatCtx_Out->streams[VideoIndex]->codec->width, 
					pFormatCtx_Out->streams[VideoIndex]->codec->height);
				
				//pts = n * (（1 / timbase）/ fps);
				picture->pts = VideoFrameIndex * ((pFormatCtx_Video->streams[0]->time_base.den / pFormatCtx_Video->streams[0]->time_base.num) / 15);

				int got_picture = 0;
				***Packet pkt;
				av_init_packet(&pkt);
				
				pkt.data = NULL;
				pkt.size = 0;
				int ret = avcodec_encode_video2(pFormatCtx_Out->streams[VideoIndex]->codec, &pkt, picture, &got_picture);
				if(ret < 0)
				{
					//编码错误,不理会此帧
					continue;
				}
				
				if (got_picture==1)
				{
 					pkt.stream_index = VideoIndex;
					pkt.pts = av_rescale_q_rnd(pkt.pts, pFormatCtx_Video->streams[0]->time_base, 
						pFormatCtx_Out->streams[VideoIndex]->time_base, (***Rounding)(***_ROUND_NEAR_INF|***_ROUND_PASS_MINMAX));  
					pkt.dts = av_rescale_q_rnd(pkt.dts,  pFormatCtx_Video->streams[0]->time_base, 
						pFormatCtx_Out->streams[VideoIndex]->time_base, (***Rounding)(***_ROUND_NEAR_INF|***_ROUND_PASS_MINMAX));  

					pkt.duration = ((pFormatCtx_Out->streams[0]->time_base.den / pFormatCtx_Out->streams[0]->time_base.num) / 15);

					cur_pts_v = pkt.pts;

					ret = av_interleaved_write_frame(pFormatCtx_Out, &pkt);
					//delete[] pkt.data;
					av_free_packet(&pkt);
				}
				VideoFrameIndex++;
			}
		}
		else
		{
			if (NULL == fifo_audio)
			{
				continue;//还未初始化fifo
			}
			if (av_audio_fifo_size(fifo_audio) < pFormatCtx_Out->streams[AudioIndex]->codec->frame_size && !bCap)
			{
				cur_pts_a = 0x7fffffffffffffff;
			}
			if(av_audio_fifo_size(fifo_audio) >= 
				(pFormatCtx_Out->streams[AudioIndex]->codec->frame_size > 0 ? pFormatCtx_Out->streams[AudioIndex]->codec->frame_size : 1024))
			{
				***Frame *frame;
				frame = av_frame_alloc();
				frame->nb_samples = pFormatCtx_Out->streams[AudioIndex]->codec->frame_size>0 ? pFormatCtx_Out->streams[AudioIndex]->codec->frame_size: 1024;
				frame->channel_layout = pFormatCtx_Out->streams[AudioIndex]->codec->channel_layout;
				frame->format = pFormatCtx_Out->streams[AudioIndex]->codec->sample_fmt;
				frame->sample_rate = pFormatCtx_Out->streams[AudioIndex]->codec->sample_rate;
				av_frame_get_buffer(frame, 0);

				EnterCriticalSection(&AudioSection);
				av_audio_fifo_read(fifo_audio, (void **)frame->data, 
					(pFormatCtx_Out->streams[AudioIndex]->codec->frame_size > 0 ? pFormatCtx_Out->streams[AudioIndex]->codec->frame_size : 1024));
				LeaveCriticalSection(&AudioSection);

				if (pFormatCtx_Out->streams[0]->codec->sample_fmt != pFormatCtx_Audio->streams[AudioIndex]->codec->sample_fmt 
					|| pFormatCtx_Out->streams[0]->codec->channels != pFormatCtx_Audio->streams[AudioIndex]->codec->channels 
					|| pFormatCtx_Out->streams[0]->codec->sample_rate != pFormatCtx_Audio->streams[AudioIndex]->codec->sample_rate)
				{
					//如果输入和输出的音频格式不一样 需要重采样，这里是一样的就没做
				}

				***Packet pkt_out;
				av_init_packet(&pkt_out);
				int got_picture = -1;
				pkt_out.data = NULL;
				pkt_out.size = 0;

				frame->pts = AudioFrameIndex * pFormatCtx_Out->streams[AudioIndex]->codec->frame_size;
				if (avcodec_encode_audio2(pFormatCtx_Out->streams[AudioIndex]->codec, &pkt_out, frame, &got_picture) < 0)
				{
					printf("can not decoder a frame");
				}
				av_frame_free(&frame);
				if (got_picture) 
				{
					pkt_out.stream_index = AudioIndex;
					pkt_out.pts = AudioFrameIndex * pFormatCtx_Out->streams[AudioIndex]->codec->frame_size;
					pkt_out.dts = AudioFrameIndex * pFormatCtx_Out->streams[AudioIndex]->codec->frame_size;
					pkt_out.duration = pFormatCtx_Out->streams[AudioIndex]->codec->frame_size;

					cur_pts_a = pkt_out.pts;
					
					int ret = av_interleaved_write_frame(pFormatCtx_Out, &pkt_out);
					av_free_packet(&pkt_out);
				}
				AudioFrameIndex++;
			}
		}
	}

	delete[] picture_buf;

	av_fifo_free(fifo_video);
	av_audio_fifo_free(fifo_audio);

	av_write_trailer(pFormatCtx_Out);

	avio_close(pFormatCtx_Out->pb);
	avformat_free_context(pFormatCtx_Out);

	if (pFormatCtx_Video != NULL)
	{
		avformat_close_input(&pFormatCtx_Video);
		pFormatCtx_Video = NULL;
	}
	if (pFormatCtx_Audio != NULL)
	{
		avformat_close_input(&pFormatCtx_Audio);
		pFormatCtx_Audio = NULL;
	}

	return 0;
}

DWORD WINAPI ScreenCapThreadProc( LPVOID lpParam )
{
	***Packet packet;/* = (***Packet *)av_malloc(sizeof(***Packet))*/;
	int got_picture;
	***Frame	*pFrame;
	pFrame=avcodec_alloc_frame();

	***Frame *picture = avcodec_alloc_frame();
	int size = avpicture_get_size(pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt, 
		pFormatCtx_Out->streams[VideoIndex]->codec->width, pFormatCtx_Out->streams[VideoIndex]->codec->height);
	//picture_buf = new uint8_t[size];

	avpicture_fill((***Picture *)picture, picture_buf, 
		pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt, 
		pFormatCtx_Out->streams[VideoIndex]->codec->width, 
		pFormatCtx_Out->streams[VideoIndex]->codec->height);

	FILE *p = NULL;
	p = fopen("proc_test.yuv", "wb+");
	av_init_packet(&packet);
	int height = pFormatCtx_Out->streams[VideoIndex]->codec->height;
	int width = pFormatCtx_Out->streams[VideoIndex]->codec->width;
	int y_size=height*width;
	while(bCap)
	{
		packet.data = NULL;
		packet.size = 0;
		if (av_read_frame(pFormatCtx_Video, &packet) < 0)
		{
			continue;
		}
		if(packet.stream_index == 0)
		{
			if (avcodec_decode_video2(pCodecCtx_Video, pFrame, &got_picture, &packet) < 0)
			{
				printf("Decode Error.（解码错误）\n");
				continue;
			}
			if (got_picture)
			{
				sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, 
					pFormatCtx_Out->streams[VideoIndex]->codec->height, picture->data, picture->linesize);
				
				if (av_fifo_space(fifo_video) >= size)
				{
					EnterCriticalSection(&VideoSection);					
					av_fifo_generic_write(fifo_video, picture->data[0], y_size, NULL);
					av_fifo_generic_write(fifo_video, picture->data[1], y_size/4, NULL);
					av_fifo_generic_write(fifo_video, picture->data[2], y_size/4, NULL);
					LeaveCriticalSection(&VideoSection);
				}
			}
		}
		av_free_packet(&packet);
		//Sleep(50);
	}
	av_frame_free(&pFrame);
	av_frame_free(&picture);
	//delete[] picture_buf;
	return 0;
}

DWORD WINAPI AudioCapThreadProc( LPVOID lpParam )
{
	***Packet pkt;
	***Frame *frame;
	frame = av_frame_alloc();
	int gotframe;
	while(bCap)
	{
		pkt.data = NULL;
		pkt.size = 0;
		if(av_read_frame(pFormatCtx_Audio,&pkt) < 0)
		{
			continue;
		}
		
		if (avcodec_decode_audio4(pFormatCtx_Audio->streams[0]->codec, frame, &gotframe, &pkt) < 0)
		{
			av_frame_free(&frame);
			printf("can not decoder a frame");
			break;
		}
		av_free_packet(&pkt);

		if (!gotframe)
		{
			continue;//没有获取到数据，继续下一次
		}

		if (NULL == fifo_audio)
		{
			fifo_audio = av_audio_fifo_alloc(pFormatCtx_Audio->streams[0]->codec->sample_fmt, 
				pFormatCtx_Audio->streams[0]->codec->channels, 30 * frame->nb_samples);
		}

		int buf_space = av_audio_fifo_space(fifo_audio);
		if (av_audio_fifo_space(fifo_audio) >= frame->nb_samples)
		{
			EnterCriticalSection(&AudioSection);
			av_audio_fifo_write(fifo_audio, (void **)frame->data, frame->nb_samples);
			LeaveCriticalSection(&AudioSection);
		}
	}
	av_frame_free(&frame);
	return 0;
}

注：上面的代码已经过修改，请重新下载工程(或者用代码覆盖以前的版本)。//8-25-15

3、工程地址

http://download.csdn.net/detail/dancing_night/9044441