技术

ntoskrnl.ExiAcquireFastMutex HAL.dll

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在32位Win7操作系统里，运行引用我们编的动态库的应用程序，报如下错误:

无法定位程序输入点 ntoskrnl.ExiAcquireFastMutex 于动态链接库 HAL.dll 上。

用Dependency Walker查看我们编的动态库，发现引用了ntoskrnl.exe，猜测在旧有的32位win32环境中是不会从dll中去引用别的exe的。只有在64位win32环境中才会存在从dll中去引用ntoskrnl.exe。

32位动态库编译的解决办法:
链接器->输入->附加依赖项去除ucrt.lib和wdm.lib。
链接器->输入->忽略所有默认库设为否。
链接器->高级->入口点清空。

addr2line ??

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gcc中加入编译选项

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g++ -g -Wl,-Map=test.map -no-pie -rdynamic ...

内核设置如下

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echo 0 > /proc/sys/kernel/randomize_va_space

addr2line

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addr2line -e ./test -Cif 0x401425

vim+cscope

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apt install vim
apt install cscope

将以下脚本保存为~/.vimrc，注意要用dos2unix转换一下

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	if has("cscope")
		set csprg=/usr/bin/cscope
		set csto=0
		set cst
		set nocsverb
		" add any database in current directory
		if filereadable("cscope.out")
		    cs add cscope.out
		" else add database pointed to by environment
		elseif $CSCOPE_DB != ""
		    cs add $CSCOPE_DB
		endif
		set csverb
	endif
 
	nmap <C-[>s :scs find s <C-R>=expand("<cword>")<CR><CR>
	nmap <C-[>g :scs find g <C-R>=expand("<cword>")<CR><CR>
	nmap <C-[>c :scs find c <C-R>=expand("<cword>")<CR><CR>
	nmap <C-[>t :scs find t <C-R>=expand("<cword>")<CR><CR>
	nmap <C-[>e :scs find e <C-R>=expand("<cword>")<CR><CR>
	nmap <C-[>f :scs find f <C-R>=expand("<cfile>")<CR><CR>
	nmap <C-[>i :scs find i ^<C-R>=expand("<cfile>")<CR>$<CR>
	nmap <C-[>d :scs find d <C-R>=expand("<cword>")<CR><CR>
	nmap <C-[>a :scs find a <C-R>=expand("<cword>")<CR><CR>

每次源码更新时，在源码根目录执行

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find . -type f | cat > cscope.files
cscope -bq

编译Android版本的OpenSSL

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将android-ndk-r20b和openssl-master解压在同一层目录，在此目录创建脚本bld.sh，内容如下

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#!/bin/sh
 
BASE_DIR=/home/sdb/android/ndk-r20b
 
export ANDROID_NDK_HOME=${BASE_DIR}/android-ndk-r20b
 
PATH=$ANDROID_NDK_HOME/toolchains/llvm/prebuilt/linux-x86_64/bin:$ANDROID_NDK_HOME/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin:$PATH
 
cd openssl-master/
 
#./Configure --prefix=${BASE_DIR}/openssl-arm32 android-arm -D__ANDROID_API__=29
./Configure --prefix=${BASE_DIR}/openssl-arm32 android-arm -D__ANDROID_API__=16
#./Configure --prefix=${BASE_DIR}/openssl-x86 android-x86 -D__ANDROID_API__=16
 
make
make install

运行bld.sh脚本就会生成OpenSSL库文件。

How to build rtsp stream from a mp4 file to test EuhatRtsp

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First, convert mp4 file to h264 file, save script below named convert.bat

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ffmpeg.exe -i %1 -s 1920x1080 -b:v 1536K -an output.mp4
ffmpeg -i output.mp4 -codec copy -bsf: h264_mp4toannexb -f h264 output.264

drag a mp4 file over convert.bat, after a while, output.264 will be generated. download h264LiveMediaServer.zip, unzip as h264LiveMediaServer.exe, move it to the same directory with output.264, just double click and run h264LiveMediaServer.exe, it will notify you the rtsp url, then input the url in the url edit box on the EuhatRtsp Demo app ui, click begin button, wait several seconds, you will see the video rendering in EuhatRtsp.

Before running h264LiveMediaServer.exe, vc2019 x86 Redistributable must be installed.

Visit H264LiveMediaServer on Github to get the source code.