C++ 屏幕录像机
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Screen recorder
提问by ComputerSaysNo
I'm interested in a library(for windows) written in Delphi/Pascal or C++ that allows me to record(to a video format) desktop screen, requirements:
我对用 Delphi/Pascal 或 C++ 编写的库（用于 Windows）感兴趣，它允许我记录（到视频格式）桌面屏幕，要求：
- must be able to specify the frame rate, or at least be able to record @ 5fps;
- must be open source or free;
- the output format could be almost any, but the quality must be good enough to be able to read text from the recording;
- 必须能够指定帧率，或者至少能够录制@5fps；
- 必须是开源的或免费的；
- 输出格式几乎可以是任何格式，但质量必须足够好，以便能够从录音中读取文本；
pluses, if possible:
优点，如果可能的话：
- option to record without colors(grayscale);
- multiple display aware;
- cross platform(Windows & Linux, other platforms would be nice as well, but not necessary);
- 没有颜色记录的选项（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）；
If by any chance, I didn't explain something right, please feel free to ask so I can rephrase or give more details, etc.
如果有任何机会，我没有解释正确的东西，请随时提问，以便我可以改写或提供更多细节等。
采纳答案by Marcus Adams
回答by yms
You could try Windows Media Encoder(freeware, wmv/asf only) or VLC(GPL, Win/OSX/Linux). Be aware that "hardware accelerated" views (Direct3D & OpenGL rendering for example) will not be available, and some quality loss will be experienced due to video compression. How much you lose will depend on your settings (codec, bitrate, resolution, etc)
您可以尝试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，并且由于视频压缩会导致一些质量损失。您损失多少取决于您的设置（编解码器、比特率、分辨率等）
Example: How to Stream your Desktop using VLC
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}'
You can find more options in VLC documentation, for saving your stream as a file for example.
您可以在VLC 文档中找到更多选项，例如将流保存为文件。
回答by LaKraven
This is the one I use with Delphi, it's called "Professional Screen Camera Component". Admittedly I had to make some changes to support unicode versions (replace PChar with PAnsiChar, replace Char with AnsiChar).
这是我在 Delphi 中使用的一个，它被称为“专业屏幕相机组件”。诚然，我必须做出一些更改以支持 unicode 版本（用 PAnsiChar 替换 PChar，用 AnsiChar 替换 Char）。
It'll happily record away at whatever framerate I set it to, will encode the video with whatever codec I specify (if I want it to), and allows you to specify the region you wish to record.
它会很高兴地以我设置的任何帧速率录制，将使用我指定的任何编解码器对视频进行编码（如果我愿意的话），并允许您指定要录制的区域。
Comes with a demo project too!
还附带一个演示项目！
Oh, and it's free/open source!
哦，它是免费/开源的！
回答by Abdullah Farweez
FFmpeg can be used to capture the screen.
FFmpeg 可用于捕获屏幕。
watch the screen recorded video demo using FFMPEG : https://www.youtube.com/watch?v=a31bBY3HuxE
使用 FFMPEG 观看屏幕录制的视频演示：https: //www.youtube.com/watch?v=a31bBY3HuxE
Container format : MP4
容器格式：MP4
Codec : MPEG4
编解码器：MPEG4
Follow the steps to record the screen in video using FFmpeg and other libraries.
按照步骤使用 FFmpeg 和其他库在视频中录制屏幕。
Initialize required registers
use x11grab(for linux OS) in av_find_input_format
mention the posistion to capture the video in screen (Eg. ":0.0+10,250" in av_format_open_input)
Now go for regular video parameters initialization and memory allocation.
start capturing the frames and store it in a file.
Finally, release the allocated resources once completed !.
初始化所需的寄存器
在 av_find_input_format 中使用 x11grab(for linux OS)
提及在屏幕中捕获视频的位置（例如 av_format_open_input 中的“:0.0+10,250”）
现在进行常规视频参数初始化和内存分配。
开始捕获帧并将其存储在文件中。
最后，完成后释放分配的资源！。
below code is written in c++ and uses linux(ubuntu) platform video format is in mp4 format.
下面的代码是用 c++ 编写的，并使用 linux(ubuntu) 平台视频格式为 mp4 格式。
// 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 */
Here's the screenshot.
这是屏幕截图。
回答by ByteArts
It is probably overkill for your needs, but the video grabber component from DataStead can also record screen activity and save the output as video file. See http://www.datastead.com/products/tvideograbber/overview.html. I'm not associated with DataStead, but have been a customer for a few years and it works great.
这对于您的需求来说可能有点过头了，但 DataStead 的视频采集器组件还可以记录屏幕活动并将输出保存为视频文件。请参阅http://www.datastead.com/products/tvideograbber/overview.html。我与 DataStead 没有关联，但我已经成为客户几年了，而且效果很好。
回答by John Humphreys - w00te
I haven't done this myself before, but when I googled around (as I'm sure you have), I ran into this:
我以前自己没有这样做过，但是当我用谷歌搜索时（我相信你有），我遇到了这个：
http://www.codeproject.com/KB/GDI/barry_s_screen_capture.aspx
http://www.codeproject.com/KB/GDI/barry_s_screen_capture.aspx
It looks as if it should do what you're asking reasonably easily (for Windows), and it has no license associated with it (as confirmed at the bottom). I don't believe its set up as a library, but I'm sure you could bind the interface to the sample WinCap functions into one with reasonable ease.
看起来它应该可以很容易地完成您要求的操作（对于 Windows），并且它没有与之关联的许可证（如底部确认的那样）。我不相信它被设置为一个库，但我相信你可以很容易地将接口绑定到示例 WinCap 函数。
回答by Anil8753
use screen capture lite https://github.com/smasherprog/screen_capture_lite
使用屏幕截图精简版 https://github.com/smasherprog/screen_capture_lite
This is a C++ library and cross-platform
这是一个 C++ 库和跨平台
