屏幕录像机

我对使用Delphi / Pascal或C ++编写的库（对于Windows）感兴趣，它允许我logging（以video格式）桌面屏幕，要求：

• 必须能够指定帧速率，或者至less能够logging@ 5fps;
• 必须是开源或免费的;
• 输出格式可以是几乎任何一种，但质量必须足够好，才能够从logging中读取文本;

如果可能的话，

• 选项无颜色logging（灰度）;
• 多显示器感知 ;
• 跨平台（Windows和Linux，其他平台也不错，但不是必需的）;

如果有机会的话，我没有解释正确的东西，请随时提问，以便我可以重新修改或提供更多的细节等。

Answer 1

FFMPEG支持屏幕截图（投射）并且是跨平台的。

Answer 2

您可以尝试使用Windows Media Encoder （免费软件，仅限wmv / asf）或VLC （GPL，Win / OSX / Linux）。 请注意，“硬件加速”视图（例如Direct3D和OpenGL渲染）将不可用，并且video压缩会导致一些质量损失。 你失去多less将取决于你的设置（编解码器，比特率，分辨率等）

示例： 如何使用VLCstream式传输桌面

vlc screen:// :screen-fps=30 :screen-caching=100 --sout '#transcode{vcodec=mp4v,vb=4096,acodec=mpga,ab=256,scale=1,width=1280,height=800}:rtp{dst=192.168.1.2,port=1234,access=udp,mux=ts}' 

您可以在VLC文档中find更多选项，例如将文件stream保存为文件。

Answer 3

这是我用Delphi的，叫做“ 专业屏幕摄像头组件 ”。 无可否认，我不得不做一些更改以支持unicode版本（用PAnsiCharreplacePChar，用AnsiCharreplaceChar）。

它会高兴地logging下我设置的任何帧率，将video编码为我指定的任何编解码器（如果我想要的话），并允许您指定您想要logging的区域。

还有一个演示项目呢！

哦，它是免费的/开源的！

Answer 4

我以前没有这样做过，但当我四处搜寻时（我确定你有），我碰到了这个：

http://www.codeproject.com/KB/GDI/barry_s_screen_capture.aspx

它看起来好像它应该做你所要求的（Windows的）合理的，而且它没有与之关联的许可证（如在底部所证实的那样）。 我不相信它被设置为一个库，但我相信你可以将接口与示例WinCap函数绑定到一个合理的简单。

Answer 5

这可能是你的需要矫枉过正，但DataStead公司的video采集卡组件也可以logging屏幕活动并将输出保存为video文件。 请参阅http://www.datastead.com/products/tvideograbber/overview.html 。 我与DataStead没有任何关系，但几年来一直是客户，而且效果很好。

Answer 6

FFmpeg可以用来捕捉屏幕。

使用FFMPEG观看屏幕录制的video演示： https ： //www.youtube.com/watch？v = a31bBY3HuxE

容器格式：MP4

编解码器：MPEG4

按照步骤使用FFmpeg和其他库来loggingvideo中的屏幕。

1. 初始化所需的寄存器

2. 在av_find_input_format中使用x11grab（用于linux操作系统）

3. 提及在屏幕上捕获video的位置（例如，av_format_open_input中的“0.0 + 10,250”）：

4. 现在去定期的video参数初始化和内存分配。

5. 开始捕获帧并将其存储在一个文件中。

6. 最后，一旦完成，释放分配的资源。

下面的代码是用c ++编写的，使用linux（ubuntu）平台的video格式是mp4格式的。

 // sample code to record the computer screen ! #ifndef SCREENRECORDER_H #define SCREENRECORDER_H #include <iostream> #include <cstdio> #include <cstdlib> #include <fstream> #include <cstring> #include <math.h> #include <string.h> #define __STDC_CONSTANT_MACROS //FFMPEG LIBRARIES extern "C" { #include "libavcodec/avcodec.h" #include "libavcodec/avfft.h" #include "libavdevice/avdevice.h" #include "libavfilter/avfilter.h" #include "libavfilter/avfiltergraph.h" #include "libavfilter/buffersink.h" #include "libavfilter/buffersrc.h" #include "libavformat/avformat.h" #include "libavformat/avio.h" // libav resample #include "libavutil/opt.h" #include "libavutil/common.h" #include "libavutil/channel_layout.h" #include "libavutil/imgutils.h" #include "libavutil/mathematics.h" #include "libavutil/samplefmt.h" #include "libavutil/time.h" #include "libavutil/opt.h" #include "libavutil/pixdesc.h" #include "libavutil/file.h" // lib swresample #include "libswscale/swscale.h" } class ScreenRecorder { private: AVInputFormat *pAVInputFormat; AVOutputFormat *output_format; AVCodecContext *pAVCodecContext; AVFormatContext *pAVFormatContext; AVFrame *pAVFrame; AVFrame *outFrame; AVCodec *pAVCodec; AVCodec *outAVCodec; AVPacket *pAVPacket; AVDictionary *options; AVOutputFormat *outAVOutputFormat; AVFormatContext *outAVFormatContext; AVCodecContext *outAVCodecContext; AVStream *video_st; AVFrame *outAVFrame; const char *dev_name; const char *output_file; double video_pts; int out_size; int codec_id; int value; int VideoStreamIndx; public: ScreenRecorder(); ~ScreenRecorder(); int openCamera(); int init_outputfile(); int collectFrames(); }; #endif using namespace std; ScreenRecorder::ScreenRecorder() { cout<<"\n\n Registering required functions..."; av_register_all(); avcodec_register_all(); avdevice_register_all(); cout<<"\n\n Registered successfully..."; } ScreenRecorder::~ScreenRecorder() { avformat_close_input(&pAVFormatContext); if( !pAVFormatContext ) { cout<<"\n\n1.Success : avformat_close_input()"; } else { cout<<"\n\nError : avformat_close_input()"; } avformat_free_context(pAVFormatContext); if( !pAVFormatContext ) { cout<<"\n\n2.Success : avformat_free_context()"; } else { cout<<"\n\nError : avformat_free_context()"; } cout<<"\n\n---------------Successfully released all resources------------------\n\n\n"; cout<<endl; cout<<endl; cout<<endl; } int ScreenRecorder::collectFrames() { int flag; int frameFinished; //when you decode a single packet, you still don't have information enough to have a frame [depending on the type of codec, some of them //you do], when you decode a GROUP of packets that represents a frame, then you have a picture! that's why frameFinished will let //you know you decoded enough to have a frame. int frame_index = 0; value = 0; pAVPacket = (AVPacket *)av_malloc(sizeof(AVPacket)); av_init_packet(pAVPacket); pAVFrame = av_frame_alloc(); if( !pAVFrame ) { cout<<"\n\nError : av_frame_alloc()"; return -1; } outFrame = av_frame_alloc();//Allocate an AVFrame and set its fields to default values. if( !outFrame ) { cout<<"\n\nError : av_frame_alloc()"; return -1; } int video_outbuf_size; int nbytes = av_image_get_buffer_size(outAVCodecContext->pix_fmt,outAVCodecContext->width,outAVCodecContext->height,32); uint8_t *video_outbuf = (uint8_t*)av_malloc(nbytes); if( video_outbuf == NULL ) { cout<<"\n\nError : av_malloc()"; } // Setup the data pointers and linesizes based on the specified image parameters and the provided array. value = av_image_fill_arrays( outFrame->data, outFrame->linesize, video_outbuf , AV_PIX_FMT_YUV420P, outAVCodecContext->width,outAVCodecContext->height,1 ); // returns : the size in bytes required for src if(value < 0) { cout<<"\n\nError : av_image_fill_arrays()"; } SwsContext* swsCtx_ ; // Allocate and return swsContext. // a pointer to an allocated context, or NULL in case of error // Deprecated : Use sws_getCachedContext() instead. swsCtx_ = sws_getContext(pAVCodecContext->width, pAVCodecContext->height, pAVCodecContext->pix_fmt, outAVCodecContext->width, outAVCodecContext->height, outAVCodecContext->pix_fmt, SWS_BICUBIC, NULL, NULL, NULL); int ii = 0; int no_frames = 100; cout<<"\n\nEnter No. of Frames to capture : "; cin>>no_frames; AVPacket outPacket; int j = 0; int got_picture; while( av_read_frame( pAVFormatContext , pAVPacket ) >= 0 ) { if( ii++ == no_frames )break; if(pAVPacket->stream_index == VideoStreamIndx) { value = avcodec_decode_video2( pAVCodecContext , pAVFrame , &frameFinished , pAVPacket ); if( value < 0) { cout<<"Error : avcodec_decode_video2()"; } if(frameFinished)// Frame successfully decoded :) { sws_scale(swsCtx_, pAVFrame->data, pAVFrame->linesize,0, pAVCodecContext->height, outFrame->data,outFrame->linesize); av_init_packet(&outPacket); outPacket.data = NULL; // packet data will be allocated by the encoder outPacket.size = 0; avcodec_encode_video2(outAVCodecContext , &outPacket ,outFrame , &got_picture); if(got_picture) { if(outPacket.pts != AV_NOPTS_VALUE) outPacket.pts = av_rescale_q(outPacket.pts, video_st->codec->time_base, video_st->time_base); if(outPacket.dts != AV_NOPTS_VALUE) outPacket.dts = av_rescale_q(outPacket.dts, video_st->codec->time_base, video_st->time_base); printf("Write frame %3d (size= %2d)\n", j++, outPacket.size/1000); if(av_write_frame(outAVFormatContext , &outPacket) != 0) { cout<<"\n\nError : av_write_frame()"; } av_packet_unref(&outPacket); } // got_picture av_packet_unref(&outPacket); } // frameFinished } }// End of while-loop value = av_write_trailer(outAVFormatContext); if( value < 0) { cout<<"\n\nError : av_write_trailer()"; } //THIS WAS ADDED LATER av_free(video_outbuf); } int ScreenRecorder::openCamera() { value = 0; options = NULL; pAVFormatContext = NULL; pAVFormatContext = avformat_alloc_context();//Allocate an AVFormatContext. pAVInputFormat = av_find_input_format("x11grab"); value = avformat_open_input(&pAVFormatContext, ":0.0+10,250", pAVInputFormat, NULL); if(value != 0) { cout<<"\n\nError : avformat_open_input\n\nstopped..."; return -1; } value = av_dict_set( &options,"framerate","30",0 ); if(value < 0) { cout<<"\n\nError : av_dict_set(framerate , 30 , 0)"; return -1; } value = av_dict_set( &options, "preset", "medium", 0 ); if(value < 0) { cout<<"\n\nError : av_dict_set(preset , medium)"; return -1; } // value = avformat_find_stream_info(pAVFormatContext,NULL); if(value < 0) { cout<<"\n\nError : avformat_find_stream_info\nstopped..."; return -1; } VideoStreamIndx = -1; for(int i = 0; i < pAVFormatContext->nb_streams; i++ ) // find video stream posistion/index. { if( pAVFormatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO ) { VideoStreamIndx = i; break; } } // End for-loop if( VideoStreamIndx == -1) { cout<<"\n\nError : VideoStreamIndx = -1"; return -1; } // assign pAVFormatContext to VideoStreamIndx pAVCodecContext = pAVFormatContext->streams[VideoStreamIndx]->codec; pAVCodec = avcodec_find_decoder(pAVCodecContext->codec_id); if( pAVCodec == NULL ) { cout<<"\n\nError : avcodec_find_decoder()"; return -1; } value = avcodec_open2(pAVCodecContext , pAVCodec , NULL);//Initialize the AVCodecContext to use the given AVCodec. if( value < 0 ) { cout<<"\n\nError : avcodec_open2()"; return -1; } } int ScreenRecorder::init_outputfile() { outAVFormatContext = NULL; value = 0; output_file = "output.mp4"; avformat_alloc_output_context2(&outAVFormatContext, NULL, NULL, output_file); if (!outAVFormatContext) { cout<<"\n\nError : avformat_alloc_output_context2()"; return -1; } /*Returns the output format in the list of registered output formats which best matches the provided parameters, or returns NULL if there is no match. */ output_format = av_guess_format(NULL, output_file ,NULL); if( !output_format ) { cout<<"\n\nError : av_guess_format()"; return -1; } video_st = avformat_new_stream(outAVFormatContext ,NULL); if( !video_st ) { cout<<"\n\nError : avformat_new_stream()"; return -1; } outAVCodecContext = avcodec_alloc_context3(outAVCodec); if( !outAVCodecContext ) { cout<<"\n\nError : avcodec_alloc_context3()"; return -1; } outAVCodecContext = video_st->codec; outAVCodecContext->codec_id = AV_CODEC_ID_MPEG4;// AV_CODEC_ID_MPEG4; // AV_CODEC_ID_H264 // AV_CODEC_ID_MPEG1VIDEO outAVCodecContext->codec_type = AVMEDIA_TYPE_VIDEO; outAVCodecContext->pix_fmt = AV_PIX_FMT_YUV420P; outAVCodecContext->bit_rate = 400000; // 2500000 outAVCodecContext->width = 1920; outAVCodecContext->height = 1080; outAVCodecContext->gop_size = 3; outAVCodecContext->max_b_frames = 2; outAVCodecContext->time_base.num = 1; outAVCodecContext->time_base.den = 30; // 15fps if (codec_id == AV_CODEC_ID_H264) { av_opt_set(outAVCodecContext->priv_data, "preset", "slow", 0); } outAVCodec = avcodec_find_encoder(AV_CODEC_ID_MPEG4); if( !outAVCodec ) { cout<<"\n\nError : avcodec_find_encoder()"; return -1; } // Some container formats (like MP4) require global headers to be present // Mark the encoder so that it behaves accordingly. if ( outAVFormatContext->oformat->flags & AVFMT_GLOBALHEADER) { outAVCodecContext->flags |= AV_CODEC_FLAG_GLOBAL_HEADER; } value = avcodec_open2(outAVCodecContext, outAVCodec, NULL); if( value < 0) { cout<<"\n\nError : avcodec_open2()"; return -1; } if ( !(outAVFormatContext->flags & AVFMT_NOFILE) ) { if( avio_open2(&outAVFormatContext->pb , output_file , AVIO_FLAG_WRITE ,NULL, NULL) < 0 ) { cout<<"\n\nError : avio_open2()"; } } if(!outAVFormatContext->nb_streams) { cout<<"\n\nError : Output file dose not contain any stream"; return -1; } value = avformat_write_header(outAVFormatContext , &options); if(value < 0) { cout<<"\n\nError : avformat_write_header()"; return -1; } cout<<"\n\nOutput file information :\n\n"; av_dump_format(outAVFormatContext , 0 ,output_file ,1); } int main() { ScreenRecorder s_record; s_record.openCamera(); s_record.init_outputfile(); s_record.collectFrames(); cout<<"\n\n---------EXIT_SUCCESS------------\n\n"; return 0; } /* to compile the code : g++ -Wno-format-zero-length -Wno-write-strings -L/home/abdullah/ffmpeg_build/lib/ -L/usr/lib/x86_64-linux-gnu/ -I/home/abdullah/ffmpeg_build/include/ -o ScreenRecorder ScreenRecorder.cpp -lavdevice -lavfilter -lswscale -lavformat -lavcodec -lavutil -lswresample -lm -lva -lpthread -lvorbis -lvpx -lopus -lz -lpostproc -ldl -lfdk-aac -lmp3lame -lvorbisenc -lvorbisfile -lx264 -ltheora -lx265 -ltheoraenc -ltheoradec -ldl -lrt -lbz2 -lasound -lSDL -lSDLmain -lSDL_ttf -lfreetype -lass -llzma -lftgl -lperl -lcrypto -lxcb -lxcb-shm -lxcb-xfixes -lao -lxcb-shape -lfftw3 */ 

这是截图。

完整的工作代码在github链接 ：