FFmpeg-通过管道馈送原始帧-FFmpeg不检测管道闭合 我试图从Windows中的C++中学习这些例子。p>
我有一个应用程序,它可以生成原始帧,并用FFmpeg编码。 原始框架通过IPC管道传输至FFmpegs标准DIN。正如预期的那样,FFmpeg甚至可以显示当前可用的帧数 当我们发送完帧时,问题就出现了。当我关闭管道的写入端时,我希望FFmpeg能够检测到它,完成并输出视频。但事实并非如此。FFmpeg保持开放状态,似乎在等待更多数据 我在VisualStudio中做了一个小测试项目FFmpeg-通过管道馈送原始帧-FFmpeg不检测管道闭合 我试图从Windows中的C++中学习这些例子。p>,c++,video,cmd,ffmpeg,pipe,C++,Video,Cmd,Ffmpeg,Pipe,我有一个应用程序,它可以生成原始帧,并用FFmpeg编码。 原始框架通过IPC管道传输至FFmpegs标准DIN。正如预期的那样,FFmpeg甚至可以显示当前可用的帧数 当我们发送完帧时,问题就出现了。当我关闭管道的写入端时,我希望FFmpeg能够检测到它,完成并输出视频。但事实并非如此。FFmpeg保持开放状态,似乎在等待更多数据 我在VisualStudio中做了一个小测试项目 #include "stdafx.h" //// stdafx.h //#include "targetver
#include "stdafx.h"
//// stdafx.h
//#include "targetver.h"
//#include <stdio.h>
//#include <tchar.h>
//#include <iostream>
#include "Windows.h"
#include <cstdlib>
using namespace std;
bool WritePipe(void* WritePipe, const UINT8 *const Buffer, const UINT32 Length)
{
if (WritePipe == nullptr || Buffer == nullptr || Length == 0)
{
cout << __FUNCTION__ << ": Some input is useless";
return false;
}
// Write to pipe
UINT32 BytesWritten = 0;
UINT8 newline = '\n';
bool bIsWritten = WriteFile(WritePipe, Buffer, Length, (::DWORD*)&BytesWritten, nullptr);
cout << __FUNCTION__ << " Bytes written to pipe " << BytesWritten << endl;
//bIsWritten = WriteFile(WritePipe, &newline, 1, (::DWORD*)&BytesWritten, nullptr); // Do we need this? Actually this should destroy the image.
FlushFileBuffers(WritePipe); // Do we need this?
return bIsWritten;
}
#define PIXEL 80 // must be multiple of 8. Otherwise we get warning: Bytes are not aligned
int main()
{
HANDLE PipeWriteEnd = nullptr;
HANDLE PipeReadEnd = nullptr;
{
// create us a pipe for inter process communication
SECURITY_ATTRIBUTES Attr = { sizeof(SECURITY_ATTRIBUTES), NULL, true };
if (!CreatePipe(&PipeReadEnd, &PipeWriteEnd, &Attr, 0))
{
cout << "Could not create pipes" << ::GetLastError() << endl;
system("Pause");
return 0;
}
}
// Setup the variables needed for CreateProcess
// initialize process attributes
SECURITY_ATTRIBUTES Attr;
Attr.nLength = sizeof(SECURITY_ATTRIBUTES);
Attr.lpSecurityDescriptor = NULL;
Attr.bInheritHandle = true;
// initialize process creation flags
UINT32 CreateFlags = NORMAL_PRIORITY_CLASS;
CreateFlags |= CREATE_NEW_CONSOLE;
// initialize window flags
UINT32 dwFlags = 0;
UINT16 ShowWindowFlags = SW_HIDE;
if (PipeWriteEnd != nullptr || PipeReadEnd != nullptr)
{
dwFlags |= STARTF_USESTDHANDLES;
}
// initialize startup info
STARTUPINFOA StartupInfo = {
sizeof(STARTUPINFO),
NULL, NULL, NULL,
(::DWORD)CW_USEDEFAULT,
(::DWORD)CW_USEDEFAULT,
(::DWORD)CW_USEDEFAULT,
(::DWORD)CW_USEDEFAULT,
(::DWORD)0, (::DWORD)0, (::DWORD)0,
(::DWORD)dwFlags,
ShowWindowFlags,
0, NULL,
HANDLE(PipeReadEnd),
HANDLE(nullptr),
HANDLE(nullptr)
};
LPSTR ffmpegURL = "\"PATHTOFFMPEGEXE\" -y -loglevel verbose -f rawvideo -vcodec rawvideo -framerate 1 -video_size 80x80 -pixel_format rgb24 -i - -vcodec mjpeg -framerate 1/4 -an \"OUTPUTDIRECTORY\"";
// Finally create the process
PROCESS_INFORMATION ProcInfo;
if (!CreateProcessA(NULL, ffmpegURL, &Attr, &Attr, true, (::DWORD)CreateFlags, NULL, NULL, &StartupInfo, &ProcInfo))
{
cout << "CreateProcess failed " << ::GetLastError() << endl;
}
//CloseHandle(ProcInfo.hThread);
// Create images and write to pipe
#define MYARRAYSIZE (PIXEL*PIXEL*3) // each pixel has 3 bytes
UINT8* Bitmap = new UINT8[MYARRAYSIZE];
for (INT32 outerLoopIndex = 9; outerLoopIndex >= 0; --outerLoopIndex) // frame loop
{
for (INT32 innerLoopIndex = MYARRAYSIZE - 1; innerLoopIndex >= 0; --innerLoopIndex) // create the pixels for each frame
{
Bitmap[innerLoopIndex] = (UINT8)(outerLoopIndex * 20); // some gray color
}
system("pause");
if (!WritePipe(PipeWriteEnd, Bitmap, MYARRAYSIZE))
{
cout << "Failed writing to pipe" << endl;
}
}
// Done sending images. Tell the other process. IS THIS NEEDED? HOW TO TELL FFmpeg WE ARE DONE?
//UINT8 endOfFile = 0xFF; // EOF = -1 == 1111 1111 for uint8
//if (!WritePipe(PipeWriteEnd, &endOfFile, 1))
//{
// cout << "Failed writing to pipe" << endl;
//}
//FlushFileBuffers(PipeReadEnd); // Do we need this?
delete Bitmap;
system("pause");
// clean stuff up
FlushFileBuffers(PipeWriteEnd); // Do we need this?
if (PipeWriteEnd != NULL && PipeWriteEnd != INVALID_HANDLE_VALUE)
{
CloseHandle(PipeWriteEnd);
}
// We do not want to destroy the read end of the pipe? Should not as that belongs to FFmpeg
//if (PipeReadEnd != NULL && PipeReadEnd != INVALID_HANDLE_VALUE)
//{
// ::CloseHandle(PipeReadEnd);
//}
return 0;
}
正如您在te FFmpeg输出的最后一行中所看到的那样,这些图像是经过处理的。10帧可用。但是关闭管道后,FFmpeg不会关闭,仍然需要输入
正如链接的示例所示,这应该是一种有效的方法
现在试了一个星期 我终于放弃了。不知道是什么问题。改为使用套接字和TCP。在TCP连接的命令行下方
LPSTR ffmpegURL = "\"PATHTOFFMPEGEXE\" -y -loglevel verbose -f rawvideo -vcodec rawvideo -framerate 1 -video_size 80x80 -pixel_format rgb24 -i tcp://127.0.0.1:PORT_NR -vcodec mjpeg -framerate 1/4 -an \"OUTPUTDIRECTORY\"";
在这种情况下,FFmpeg是客户端并尝试连接到服务器。创建管道时,它会生成两个句柄,一个用于读取,一个用于写入:
HANDLE readPipe;
HANDLE writePipe;
SECURITY_ATTRIBUTES sa = { sizeof(sa) };
sa.lpSecurityDescriptor = nullptr;
sa.bInheritHandle = TRUE;
CreatePipe(&readPipe, &writePipe, &sa, sizeof(buffer));
请注意bInheritHandle=TRUE
标志。这允许生成的子进程(ffmpeg)继承句柄,这是它访问管道所必需的(下面的CreateProcess
函数签名中有一个类似的参数,bInheritHandles
,也设置为TRUE
)
然后启动子进程并将其stdin
映射到readPipe
:
STARTUPINFOA si = { sizeof(si) };
si.dwFlags = STARTF_USESTDHANDLES;
si.hStdInput = readPipe;
si.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
si.hStdError = GetStdHandle(STD_ERROR_HANDLE);
PROCESS_INFORMATION pi = {};
CreateProcessA(nullptr, cmd, nullptr, nullptr, TRUE, 0, nullptr, nullptr, &si, &pi);
此时,您可以开始通过WriteFile
将帧压缩到ffmpeg,该文件(如果被告知使用stdin
的输入)将进行编码。问题是当你做完了,打电话给
CloseHandle(readPipe);
CloseHandle(writePipe);
..ffmpeg一直在等待更多数据,而不是关闭文件
原因如下:
创建子进程时,它将继承所有句柄,而不仅仅是在STARTUPINFO
结构(即readPipe
)中指定的句柄。因此,它还将继承writepe
句柄。对于从readPipe
读取以生成EOF、发送ffmpeg完成并关闭的信号,必须首先关闭writepe
。但是,由于子进程具有两个句柄的副本,因此即使在您端关闭这对句柄,也不会触发客户端上的EOF,因为writepe
仍然保持活动状态
修复方法是防止继承writepe
。与此类似(在生成子进程之前):
下面是一个完整的工作源代码示例(输出一个简短的测试电影):
#包括
char*cmd=“ffmpeg-f rawvideo-pix\u fmt rgba-video\u大小1920x1080-r30-i管道:0-预设快速-y-pix\u fmt yuv420p输出.mp4”;
整数缓冲区[1920*1080];
void main()
{
处理读取管;
手柄;
安全属性sa={sizeof(sa)};
sa.lpSecurityDescriptor=nullptr;
sa.bInheritHandle=TRUE;
CreatePipe(&readPipe,&writePipe,&sa,sizeof(buffer));
SetHandleInformation(WritePie,HANDLE\u FLAG\u INHERIT,0);
StartupInfoaSi={sizeof(si)};
si.dwFlags=STARTF_USESTDHANDLES;
si.hStdInput=读取管;
si.hStdOutput=GetStdHandle(标准输出句柄);
si.hStdError=GetStdHandle(标准错误句柄);
进程信息pi={};
CreateProcessA(nullptr、cmd、nullptr、nullptr、TRUE、0、nullptr、nullptr、si和pi);
用于(int帧=0;帧<1080;帧++)
{
对于(int x=0;x<1920;x++)
{
缓冲区[帧*1920+x]=0xffffff00 |(帧*255/1079);
}
德沃德·拜特斯莱特;
WriteFile(writepe、buffer、sizeof(buffer)和byteswrite、nullptr);
}
关闭手柄(读取管);
关闭手柄(WritePie);
}
@rustyx这有什么帮助?我在frustation外试过,但没有成功。我看没问题——你试过发送几百帧吗?@MarkSetchell yah试过。没有变化。您也可以直接在命令窗口中尝试该命令行(使用合适的路径),将-video_size设置为较小的值,这样您就不必输入太多,只需将一些垃圾数据写入STDIN即可。按ENTER键后,FFmpeg仍侦听输入。好吧,这就是我希望它能做的,因为在这种情况下,标准管道没有关闭。但你会怎么告诉FFmpeg我们在这件事上完蛋了?多次点击STRG+Z使FFmpeg退出并输出视频。STRG+Z是EOF。我尝试通过程序发送EOF,但没有结果。谢谢。没有尝试你的代码,但我仍然接受它作为答案。
CloseHandle(readPipe);
CloseHandle(writePipe);
SetHandleInformation(writePipe, HANDLE_FLAG_INHERIT, 0);
#include <windows.h>
char* cmd = "ffmpeg -f rawvideo -pix_fmt rgba -video_size 1920x1080 -r 30 -i pipe:0 -preset fast -y -pix_fmt yuv420p output.mp4";
int buffer[1920 * 1080];
void main()
{
HANDLE readPipe;
HANDLE writePipe;
SECURITY_ATTRIBUTES sa = { sizeof(sa) };
sa.lpSecurityDescriptor = nullptr;
sa.bInheritHandle = TRUE;
CreatePipe(&readPipe, &writePipe, &sa, sizeof(buffer));
SetHandleInformation(writePipe, HANDLE_FLAG_INHERIT, 0);
STARTUPINFOA si = { sizeof(si) };
si.dwFlags = STARTF_USESTDHANDLES;
si.hStdInput = readPipe;
si.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
si.hStdError = GetStdHandle(STD_ERROR_HANDLE);
PROCESS_INFORMATION pi = {};
CreateProcessA(nullptr, cmd, nullptr, nullptr, TRUE, 0, nullptr, nullptr, &si, &pi);
for (int frame = 0; frame < 1080; frame++)
{
for (int x = 0; x < 1920; x++)
{
buffer[frame * 1920 + x] = 0xffffff00 | (frame * 255 / 1079);
}
DWORD bytesWritten;
WriteFile(writePipe, buffer, sizeof(buffer), &bytesWritten, nullptr);
}
CloseHandle(readPipe);
CloseHandle(writePipe);
}