最简单的基于FFmpeg的AVDevice例子(屏幕录制)
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最简单的基于FFmpeg的AVDevice例子文章列表:
最简单的基于FFmpeg的AVDevice例子(读取摄像头)
最简单的基于FFmpeg的AVDevice例子(屏幕录制)
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计划写2个有关FFmpeg的libavdevice类库的例子。上篇文章记录了一个基于FFmpeg的Libavdevice类库读取摄像头数据的例子。本篇文章记录一个基于FFmpeg的Libavdevice类库录制屏幕的例子。本文程序录制当前桌面内容并且解码显示出来。有关解码显示方面的代码本文不再详述,可以参考文章:
《100行代码实现最简单的基于FFMPEG+SDL的视频播放器(SDL1.x)》
抓屏方法
上篇文章记录了libavdevice的使用方法,本文不再重复。在Windows系统使用libavdevice抓取屏幕数据有两种方法:gdigrab和dshow。下文分别介绍。
1. gdigrab
gdigrab是FFmpeg专门用于抓取Windows桌面的设备。非常适合用于屏幕录制。它通过不同的输入URL支持两种方式的抓取:
(1)“desktop”:抓取整张桌面。或者抓取桌面中的一个特定的区域。
(2)“title={窗口名称}”:抓取屏幕中特定的一个窗口(目前中文窗口还有乱码问题)。
gdigrab另外还支持一些参数,用于设定抓屏的位置:
offset_x:抓屏起始点横坐标。
offset_y:抓屏起始点纵坐标。
video_size:抓屏的大小。
framerate:抓屏的帧率。
参考的代码如下:
//Use gdigrab AVDictionary* options = NULL; //Set some options //grabbing frame rate //av_dict_set(&options,"framerate","5",0); //The distance from the left edge of the screen or desktop //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","640x480",0); AVInputFormat *ifmt=av_find_input_format("gdigrab"); if(avformat_open_input(&pFormatCtx,"desktop",ifmt,&options)!=0){ printf("Couldn't open input stream.(无法打开输入流)\n"); return -1; }
2. dshow
使用dshow抓屏需要安装抓屏软件:screen-capture-recorder
软件地址:http://sourceforge.net/projects/screencapturer/
下载软件安装完成后,可以指定dshow的输入设备为“screen-capture-recorder”即可。有关dshow设备的使用方法在上一篇文章中已经有详细叙述,这里不再重复。参考的代码如下:
AVInputFormat *ifmt=av_find_input_format("dshow"); if(avformat_open_input(&pFormatCtx,"video=screen-capture-recorder",ifmt,NULL)!=0){ printf("Couldn't open input stream.(无法打开输入流)\n"); return -1; }
注:上述两种抓屏方法也可以直接使用ffmpeg.exe的命令行完成,可以参考文章:
FFmpeg获取DirectShow设备数据(摄像头,录屏)
在Linux下可以使用x11grab抓屏,在MacOS下可以使用avfoundation抓屏,在这里不再详细叙述。
代码
下面直接贴上程序代码:
/** * 最简单的基于FFmpeg的AVDevice例子(屏幕录制) * Simplest FFmpeg Device (Screen Capture) * * 雷霄骅 Lei Xiaohua * leixiaohua1020@126.com * 中国传媒大学/数字电视技术 * Communication University of China / Digital TV Technology * http://blog.csdn.net/leixiaohua1020 * * 本程序实现了屏幕录制功能。可以录制并播放桌面数据。是基于FFmpeg * 的libavdevice类库最简单的例子。通过该例子,可以学习FFmpeg中 * libavdevice类库的使用方法。 * 本程序在Windows下可以使用2种方式录制屏幕: * 1.gdigrab: Win32下的基于GDI的屏幕录制设备。 * 抓取桌面的时候,输入URL为“desktop”。 * 2.dshow: 使用Directshow。注意需要安装额外的软件screen-capture-recorder * 在Linux下可以使用x11grab录制屏幕。 * 在MacOS下可以使用avfoundation录制屏幕。 * * This software capture screen of computer. It's the simplest example * about usage of FFmpeg's libavdevice Library. * It's suiltable for the beginner of FFmpeg. * This software support 2 methods to capture screen in Microsoft Windows: * 1.gdigrab: Win32 GDI-based screen capture device. * Input URL in avformat_open_input() is "desktop". * 2.dshow: Use Directshow. Need to install screen-capture-recorder. * It use x11grab to capture screen in Linux. * It use avfoundation to capture screen in MacOS. */#include <stdio.h>#define __STDC_CONSTANT_MACROS#ifdef _WIN32//Windowsextern "C"{#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libswscale/swscale.h"#include "libavdevice/avdevice.h"#include "SDL/SDL.h"};#else//Linux...#ifdef __cplusplusextern "C"{#endif#include <libavcodec/avcodec.h>#include <libavformat/avformat.h>#include <libswscale/swscale.h>#include <libavdevice/avdevice.h>#include <SDL/SDL.h>#ifdef __cplusplus};#endif#endif//Output YUV420P #define OUTPUT_YUV420P 0//'1' Use Dshow //'0' Use GDIgrab#define USE_DSHOW 0//Refresh Event#define SFM_REFRESH_EVENT (SDL_USEREVENT + 1)#define SFM_BREAK_EVENT (SDL_USEREVENT + 2)int thread_exit=0;int sfp_refresh_thread(void *opaque){thread_exit=0;while (!thread_exit) {SDL_Event event;event.type = SFM_REFRESH_EVENT;SDL_PushEvent(&event);SDL_Delay(40);}thread_exit=0;//BreakSDL_Event event;event.type = SFM_BREAK_EVENT;SDL_PushEvent(&event);return 0;}//Show Dshow Devicevoid show_dshow_device(){ AVFormatContext *pFormatCtx = avformat_alloc_context(); AVDictionary* options = NULL; av_dict_set(&options,"list_devices","true",0); AVInputFormat *iformat = av_find_input_format("dshow"); printf("========Device Info=============\n"); avformat_open_input(&pFormatCtx,"video=dummy",iformat,&options); printf("================================\n");}//Show AVFoundation Devicevoid show_avfoundation_device(){ AVFormatContext *pFormatCtx = avformat_alloc_context(); AVDictionary* options = NULL; av_dict_set(&options,"list_devices","true",0); AVInputFormat *iformat = av_find_input_format("avfoundation"); printf("==AVFoundation Device Info===\n"); avformat_open_input(&pFormatCtx,"",iformat,&options); printf("=============================\n");}int main(int argc, char* argv[]){AVFormatContext*pFormatCtx;inti, videoindex;AVCodecContext*pCodecCtx;AVCodec*pCodec;av_register_all();avformat_network_init();pFormatCtx = avformat_alloc_context();//Open File//char filepath[]="src01_480x272_22.h265";//avformat_open_input(&pFormatCtx,filepath,NULL,NULL)//Register Deviceavdevice_register_all();//Windows#ifdef _WIN32#if USE_DSHOW//Use dshow////Need to Install screen-capture-recorder//screen-capture-recorder//Website: http://sourceforge.net/projects/screencapturer///AVInputFormat *ifmt=av_find_input_format("dshow");if(avformat_open_input(&pFormatCtx,"video=screen-capture-recorder",ifmt,NULL)!=0){printf("Couldn't open input stream.\n");return -1;}#else//Use gdigrabAVDictionary* options = NULL;//Set some options//grabbing frame rate//av_dict_set(&options,"framerate","5",0);//The distance from the left edge of the screen or desktop//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","640x480",0);AVInputFormat *ifmt=av_find_input_format("gdigrab");if(avformat_open_input(&pFormatCtx,"desktop",ifmt,&options)!=0){printf("Couldn't open input stream.\n");return -1;}#endif#elif defined linux//LinuxAVDictionary* options = NULL;//Set some options//grabbing frame rate//av_dict_set(&options,"framerate","5",0);//Make the grabbed area follow the mouse//av_dict_set(&options,"follow_mouse","centered",0);//Video frame size. The default is to capture the full screen//av_dict_set(&options,"video_size","640x480",0);AVInputFormat *ifmt=av_find_input_format("x11grab");//Grab at position 10,20if(avformat_open_input(&pFormatCtx,":0.0+10,20",ifmt,&options)!=0){printf("Couldn't open input stream.\n");return -1;}#else show_avfoundation_device(); //Mac AVInputFormat *ifmt=av_find_input_format("avfoundation"); //Avfoundation //[video]:[audio] if(avformat_open_input(&pFormatCtx,"1",ifmt,NULL)!=0){ printf("Couldn't open input stream.\n"); return -1; }#endifif(avformat_find_stream_info(pFormatCtx,NULL)<0){printf("Couldn't find stream information.\n");return -1;}videoindex=-1;for(i=0; i<pFormatCtx->nb_streams; i++) if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){videoindex=i;break;}if(videoindex==-1){printf("Didn't find a video stream.\n");return -1;}pCodecCtx=pFormatCtx->streams[videoindex]->codec;pCodec=avcodec_find_decoder(pCodecCtx->codec_id);if(pCodec==NULL){printf("Codec not found.\n");return -1;}if(avcodec_open2(pCodecCtx, pCodec,NULL)<0){printf("Could not open codec.\n");return -1;}AVFrame*pFrame,*pFrameYUV;pFrame=av_frame_alloc();pFrameYUV=av_frame_alloc();//unsigned char *out_buffer=(unsigned char *)av_malloc(avpicture_get_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));//avpicture_fill((AVPicture *)pFrameYUV, out_buffer, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);//SDL----------------------------if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) { printf( "Could not initialize SDL - %s\n", SDL_GetError()); return -1;} int screen_w=640,screen_h=360;const SDL_VideoInfo *vi = SDL_GetVideoInfo();//Half of the Desktop's width and height.screen_w = vi->current_w/2;screen_h = vi->current_h/2;SDL_Surface *screen; screen = SDL_SetVideoMode(screen_w, screen_h, 0,0);if(!screen) { printf("SDL: could not set video mode - exiting:%s\n",SDL_GetError()); return -1;}SDL_Overlay *bmp; bmp = SDL_CreateYUVOverlay(pCodecCtx->width, pCodecCtx->height,SDL_YV12_OVERLAY, screen); SDL_Rect rect;rect.x = 0; rect.y = 0; rect.w = screen_w; rect.h = screen_h; //SDL End------------------------int ret, got_picture;AVPacket *packet=(AVPacket *)av_malloc(sizeof(AVPacket));#if OUTPUT_YUV420P FILE *fp_yuv=fopen("output.yuv","wb+"); #endif struct SwsContext *img_convert_ctx;img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL); //------------------------------SDL_Thread *video_tid = SDL_CreateThread(sfp_refresh_thread,NULL);//SDL_WM_SetCaption("Simplest FFmpeg Grab Desktop",NULL);//Event LoopSDL_Event event;for (;;) {//WaitSDL_WaitEvent(&event);if(event.type==SFM_REFRESH_EVENT){//------------------------------if(av_read_frame(pFormatCtx, packet)>=0){if(packet->stream_index==videoindex){ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);if(ret < 0){printf("Decode Error.\n");return -1;}if(got_picture){SDL_LockYUVOverlay(bmp);pFrameYUV->data[0]=bmp->pixels[0];pFrameYUV->data[1]=bmp->pixels[2];pFrameYUV->data[2]=bmp->pixels[1]; pFrameYUV->linesize[0]=bmp->pitches[0];pFrameYUV->linesize[1]=bmp->pitches[2]; pFrameYUV->linesize[2]=bmp->pitches[1];sws_scale(img_convert_ctx, (const unsigned char* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameYUV->data, pFrameYUV->linesize);#if OUTPUT_YUV420P int y_size=pCodecCtx->width*pCodecCtx->height; fwrite(pFrameYUV->data[0],1,y_size,fp_yuv); //Y fwrite(pFrameYUV->data[1],1,y_size/4,fp_yuv); //U fwrite(pFrameYUV->data[2],1,y_size/4,fp_yuv); //V #endif SDL_UnlockYUVOverlay(bmp); SDL_DisplayYUVOverlay(bmp, &rect); }}av_free_packet(packet);}else{//Exit Threadthread_exit=1;}}else if(event.type==SDL_QUIT){thread_exit=1;}else if(event.type==SFM_BREAK_EVENT){break;}}sws_freeContext(img_convert_ctx);#if OUTPUT_YUV420P fclose(fp_yuv);#endif SDL_Quit();//av_free(out_buffer);av_free(pFrameYUV);avcodec_close(pCodecCtx);avformat_close_input(&pFormatCtx);return 0;}
结果
程序的运行效果如下。这个运行结果还是十分有趣的,会出现一个屏幕“嵌套”在另一个屏幕里面的现象,环环相套。#define OUTPUT_YUV420P 0
可以通过下面的宏定义来确定使用GDIGrab或者是Dshow打开摄像头:
//'1' Use Dshow //'0' Use GDIgrab#define USE_DSHOW 0
Simplest FFmpeg Device
项目主页
SourceForge:https://sourceforge.net/projects/simplestffmpegdevice/
Github:https://github.com/leixiaohua1020/simplest_ffmpeg_device
开源中国:http://git.oschina.net/leixiaohua1020/simplest_ffmpeg_device
http://download.csdn.net/detail/leixiaohua1020/7994049
注:
本工程包含两个基于FFmpeg的libavdevice的例子:
simplest_ffmpeg_grabdesktop:屏幕录制。
simplest_ffmpeg_readcamera:读取摄像头
更新-1.1(2015.1.9)=========================================
该版本中,修改了SDL的显示方式,弹出的窗口可以移动了。
CSDN下载地址:http://download.csdn.net/detail/leixiaohua1020/8344695
更新-1.2 (2015.2.13)=========================================
这次考虑到了跨平台的要求,调整了源代码。经过这次调整之后,源代码可以在以下平台编译通过:
VC++:打开sln文件即可编译,无需配置。
cl.exe:打开compile_cl.bat即可命令行下使用cl.exe进行编译,注意可能需要按照VC的安装路径调整脚本里面的参数。编译命令如下。
::VS2010 Environmentcall "D:\Program Files\Microsoft Visual Studio 10.0\VC\vcvarsall.bat"::include@set INCLUDE=include;%INCLUDE%::lib@set LIB=lib;%LIB%::compile and linkcl simplest_ffmpeg_grabdesktop.cpp /MD /link SDL.lib SDLmain.lib avcodec.lib ^avformat.lib avutil.lib avdevice.lib avfilter.lib postproc.lib swresample.lib swscale.lib ^/SUBSYSTEM:WINDOWS /OPT:NOREF
MinGW:MinGW命令行下运行compile_mingw.sh即可使用MinGW的g++进行编译。编译命令如下。
g++ simplest_ffmpeg_grabdesktop.cpp -g -o simplest_ffmpeg_grabdesktop.exe \-I /usr/local/include -L /usr/local/lib \-lmingw32 -lSDLmain -lSDL -lavformat -lavcodec -lavutil -lavdevice -lswscale
GCC(Linux):Linux命令行下运行compile_gcc.sh即可使用GCC进行编译。编译命令如下。
gcc simplest_ffmpeg_grabdesktop.cpp -g -o simplest_ffmpeg_grabdesktop.out \-I /usr/local/include -L /usr/local/lib -lSDLmain -lSDL -lavformat -lavcodec -lavutil -lavdevice -lswscale
GCC(MacOS):MacOS命令行下运行compile_gcc_mac.sh即可使用GCC进行编译。Mac的GCC和Linux的GCC差别不大,但是使用SDL1.2的时候,必须加上“-framework Cocoa”参数,否则编译无法通过。编译命令如下。
gcc simplest_ffmpeg_grabdesktop.cpp -g -o simplest_ffmpeg_grabdesktop.out \-framework Cocoa -I /usr/local/include -L /usr/local/lib -lSDLmain -lSDL -lavformat -lavcodec -lavutil -lavdevice -lswscale
PS:相关的编译命令已经保存到了工程文件夹中
CSDN下载地址:http://download.csdn.net/detail/leixiaohua1020/8445747
SourceForge上已经更新。
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(屏幕录制)
- 最简单的基于FFmpeg的AVDevice例子(读取摄像头)
- 最简单的基于FFmpeg的AVDevice例子(读取摄像头)
- 最简单的基于FFmpeg的AVDevice例子(读取摄像头)
- 最简单的基于FFmpeg的AVDevice例子(读取摄像头)
- 最简单的基于FFmpeg的AVDevice例子(读取摄像头)
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