I want to use the RTP data structures (e.g. RTPMuxContext in libavformat/rtpenc.h) provided by FFmpeg's libavformat however they don't seem to be available with the following install:
ffmpeg version 0.8.2.git, Copyright (c) 2000-2011 the FFmpeg developers
built on Sep 14 2011 16:04:33 with gcc 4.2.1 (Apple Inc. build 5666) (dot 3)
configuration: --enable-shared --disable-mmx --arch=x86_64
libavutil 51. 16. 0 / 51. 16. 0
libavcodec 53. 14. 0 / 53. 14. 0
libavformat 53. 12. 0 / 53. 12. 0
libavdevice 53. 3. 0 / 53. 3. 0
libavfilter 2. 40. 0 / 2. 40. 0
libswscale 2. 1. 0 / 2. 1. 0
When I look in /usr/local/include, I see the libavformat directory however only a few files are there: avformat.h, avio.h, and version.h. Of course, when I try to include libavformat/rtpenc.h I get "error: libavformat/rtpenc.h: No such file or directory"
I'd like to achieve this by dynamic linking to the FFmpeg libraries (for LGPL compliance, among other reasons), but it doesn't seem to be possible.
Is there a parameter for the configure script that I'm missing, or a post-installation step that I've neglected?
You can just include the rtpenc.h header from its existing location in the ffmpeg source directory. Since that header doesn't produce any object code your resulting binary won't be a derivative work of the ffmpeg library, but if you want you could just write a compatible structure definition in your own code and access the ffmpeg structure with a pointer/variable defined using your own definition.
Be careful because that structure is not a publicly-facing component of ffmpeg and is likely to change without warning in different versions.
Related
I'm trying to compile the same lib on two x86 separate machines.
Both use the same toolchain (exactly same set of files) but have different Glibc versions.
When I run command LD_DEBUG=libs /lib64/ld-linux-x86-64.so.2 --list ./libl2ps.so I notice the following discrepancy between the 2 Linux loaders:
Machine 1 (with Glibc 2.12):
19943: find library=libm.so.6 [0]; searching
19943: search path=/ebs/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib64:...:/ebs/frperies/repo/gnb/uplane/build_bbp/l2_ps/build/. (RPATH from file ./libl2ps.so)
19943: trying file=/ebs/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib64/libm.so.6
19943:
19943: find library=libgcc_s.so.1 [0]; searching
...
In this case the Linux loader selects lib libm.so.6 from the toolchain path based on RPATH of lib libl2ps.so.
Machine 2 (with Glibc 2.17):
10699: find library=libm.so.6 [0]; searching
10699: search path=/home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib64:/home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/lib64:/home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib:/home/frperies/repo/gnb/uplane/build_bbp/l2_ps/build/. (RPATH from file ./libl2ps.so)
10699: trying file=/home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib64/libm.so.6
10699: trying file=/home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/lib64/libm.so.6
10699: trying file=/home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib/libm.so.6
10699: trying file=/home/frperies/repo/gnb/uplane/build_bbp/l2_ps/build/./libm.so.6
10699: search cache=/etc/ld.so.cache
10699: trying file=/lib64/libm.so.6
As for Machine 1, the loader attempts from RPATH of libl2ps.so to select lib libm.so.6 from toolchain path but skip it for some reason and try further other paths. Finally it selects libm.so.6from the system path /lib64/.
The RPATH of the 2 libs lib2ps.so are exactly the same. The two files libm.so.6 are also exactly the same on both machines (checked with md5sum).
I don't understand this differences of behavior between the 2 Linux loaders.
Do you see any reason what would explain this discrepancy ?
Thank you very much for your answers.
Update:
Thank you yugr for your answer.
Output of readelf -h gives only differences on fields "Entry point address" and "Start of section headers" and there is no other differences so I think it will not help.
Regarding using dlopen()/dlerror(), I've done a little executable with the following statement:
dlopen("/home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib64/libm-2.28.so", RTLD_LAZY);
On machine 1 it works as expected:
C++ dlopen demo
Opening libm-2.28.so...
Closing library...
On machine 2 it fails and dlerror() gives the following output:
Cannot open library: /home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib64/libm-2.28.so: cannot open shared object file: No such file or directory
but the file libm-2-28.so really exists on my file system:
$ ls -l /home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic-linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib64/libm-2.28.so
-rwxr-xr-x 1 frperies linseeusers_lte_espoo 1682944 Oct 5 13:50 /home/frperies/repo/gnb/uplane/build/prefix-root/asik-x86_64-ps_lfs-dynamic- linker-on/toolchain/sysroots/core2-64-pc-linux-gnu/usr/lib64/libm-2.28.so
This is very weird, what could lead to this situation ???
Thanks
Update 2:
That is true that I haven't pointed out that machine 1 is a RHEL6.8 distro while machine 2 is RHEL7.4 distro. I (naively?) didn't think this really matters...
On machine 1:
$ cat /proc/sys/kernel/osrelease
4.4.115-1.NSN.el6.x86_64
$ uname -a
Linux sq24-3 4.4.115-1.NSN.el6.x86_64 #1 SMP Mon Feb 12 12:35:46 CET 2018 x86_64 x86_64 x86_64 GNU/Linux
$ readelf -n libl2ps.so
Notes at offset 0x00000270 with length 0x00000024:
Owner Data size Description
GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: b598468830fdf2f61eda25553b9a367c4d28cdc9
On machine 2:
$ cat /proc/sys/kernel/osrelease
3.10.0-693.el7.x86_64
$ uname -a
Linux localhost.localdomain 3.10.0-693.el7.x86_64 #1 SMP Thu Jul 6 19:56:57 EDT 2017 x86_64 x86_64 x86_64 GNU/Linux
$ readelf -n libl2ps.so
Displaying notes found at file offset 0x00000270 with length 0x00000024:
Owner Data size Description
GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: 5829181bc0502233748149369108915ea7b10e8f
Does it help ?
Thanks
Update 3:
$ readelf -n libm.so.6
Notes at offset 0x00000238 with length 0x00000024:
Owner Data size Description
GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: 0d84c7247dd76008c096719043e5592735a1c4bd
Notes at offset 0x0000025c with length 0x00000020:
Owner Data size Description
GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
OS: Linux, ABI: 4.4.0
So, how to interpret this ABI version number set to 4.4.0 ??
Thanks
Thank you yugr and Employed Russian for your answers!!
I will give it a try by upgrading my Kernel version on Machine 2.
Thanks
Regards
The error message that you see is the infamously confusing ENOENT errno. I see two instances of it in dl-load.c:
checking OS compatibility
loading non-setuid to setuid process
I suspect the first one fails in your case which would mean that OS kernel is incompatible between two machines. ld.so manpage indeed says that
Each shared object can inform the dynamic linker of the
minimum kernel ABI version that it requires. (This
requirement is encoded in an ELF note section that is viewable
via readelf -n as a section labeled NT_GNU_ABI_TAG.) At run
time, the dynamic linker determines the ABI version of the
running kernel and will reject loading shared objects that
specify minimum ABI versions that exceed that ABI version.
NT_GNU_ABI_TAG is 4.4.0 which means that you run a program expecting a minimum 4.4 kernel on a 3.10 kernel. Theoretically newer Glibc should run on older kernels as well but in your case Glibc was probly built with explicit --enable-kernel flag which prevents it's usage on kernels before 4.4 (see e.g. this explanation of --enable-kernel).
As a workaround, you may try to fool Glibc by overriding kernel version on machine 2 via
export LD_ASSUME_KERNEL=4.4.0
but it may not work if libm makes 4.4-specific syscalls that are not really present on 3.10.
I'm trying to work out how the pull checksum for packages is calculated within Alpine APK package repositories. The documentation regarding the format is lacking in any detail.
When I run apk index -o APKINDEX.unsigned.tar.gz *.apk which generates the repository. When you extract the txt file from inside the gz, it contains the following...
C:Q17KXT6xFVWz4EZDIbkcvXQ/uz9ys=
P:redis-server
V:3.2.3-0
A:noarch
S:2784844
I:102400
T:An advanced key-value store
U:http://redis.io/
L:
D:linux-headers
I'm interested in how the very first line is generated. I've tried to read the actual source that's used to generate this, but I'm not a C programmer, so it's hard for me to comprehend as it jumps all over the place.
The two files mentioned in the documentation are database.c and package.c.
Incase this somewhat helps, the original APK file has these various hashes...
CRC32 = ac17ea88
MD5 = a035ecf940a67a6572ff40afad4f396a
SHA1 = eca5d3eb11555b3e0464321b91cbd743fbb3f72b
SHA256 = 24bc1f03409b0856d84758d6d44b2f04737bbc260815c525581258a5b4bf6df4
The pull checksum is the sha1sum of the second tar.gz file in the apk file, containing the .PKGINFO file.
The Alpine APK package is actually a concatenation in disguise of 3 tar.gz files.
We can split the package below using gunzip-split into 3 .gz files, then rename them to .tar.gz
./gunzip-split -s -o ./out/ strace-5.14-r0.apk
mv ./out/file_1.gz ./out/file_1.tar.gz
mv ./out/file_2.gz ./out/file_2.tar.gz
mv ./out/file_3.gz ./out/file_3.tar.gz
sha1sum ./out/file_2.tar.gz
7a266425df7bfd7ce9a42c71a015ea2ae5715838 out/file_2.tar.gz
tar tvf out/file_2.tar.gz
-rw-r--r-- root/root 702 2021-09-03 01:34 .PKGINFO
In the case of the strace package the checksum value can be derived as above:
apk index strace-5.14-r0.apk -o APKINDEX.tar.gz
tar xvf APKINDEX.tar.gz
cat APKINDEX
echo eiZkJd97/XzppCxxoBXqKuVxWDg=|base64 -d|xxd
00000000: 7a26 6425 df7b fd7c e9a4 2c71 a015 ea2a z&d%.{.|..,q...*
00000010: e571 5838 .qX8
When comparing them we see that they match.
References
https://github.com/martencassel/apk-tools/blob/master/README.md
https://gitlab.com/cg909/gunzip-split/-/releases
https://lists.alpinelinux.org/~alpine/devel/%3C257B6969-21FD-4D51-A8EC-95CB95CEF365%40ferrisellis.com%3E#%3C20180309152107.472e4144#vostro.util.wtbts.net%3E
So...
/* Internal cointainer for MD5 or SHA1 */
struct apk_checksum {
unsigned char data[20];
unsigned char type;
};
Basically take the C: value then chop off the Q from the front then base 64 decode. Chop off the last value (type which defaults to SHA1) then you have your sha1. This appears to be made of the CONTENTS of the package but that would take further looking into it.
You need to look here: https://git.alpinelinux.org/cgit/apk-tools/tree/src/blob.c#n492
It is apk_blob_pull_csum
First 'Q' stands for encoding
Next '1' stands for SHA1
Looks like this checksum is made database.c in apk_db_unpack_pkg:
apk_sign_ctx_init(&ctx.sctx, APK_SIGN_VERIFY_IDENTITY, &pkg->csum, db->keys_fd);
tar = apk_bstream_gunzip_mpart(bs, apk_sign_ctx_mpart_cb, &ctx.sctx);
r = apk_tar_parse(tar, apk_db_install_archive_entry, &ctx, TRUE, &db->id_cache);
but I'm not sure, because I failed to trace this code.
It is really not easy to understand what are they doing.
I have configured a private APT repository (using resources on internet like http://inodes.org/2009/09/14/building-a-private-ppa-on-ubuntu/) and I'm uploading for the first time my package containing the sources of my C++ application.
So reprepro repository is empty.
I use the following command in order to start the build:
sudo reprepro -V -b /srv/reprepro processincoming incoming
Then the build start, a lot of output is genearated and I can see that pbuilder is compiling the project source code and everything is fine. I can even find in the result/ folder debian packages etc...
But the build failed with a POST_BUILD_FAILED because it seems that pbuilder has changed the douane-testing_0.8.1-apt1.debian.tar.gz file and the md5 sum is now different as shown here:
File "pool/main/d/douane-testing/douane-testing_0.8.1-apt1.debian.tar.gz" is already registered with different checksums!
md5 expected: 97257ae2c5790b84ed7bb1b412f1d518, got: df78f88b97cadc10bc0a73bf86442838
sha1 expected: ae93c44593e821696f72bee4d91ce4b6f261e529, got: d6f910ca5707ec92cb71601a4f4c72db0e5f18d9
sha256 expected: c3fac5ed112f89a8ed8d4137b34f173990d8a4b82b6212d1e0ada1cddc869b0e, got: ebdcc9ead44ea0dd99f2dc87decffcc5e3efaee64a8f62f54aec556ac19d579c
size expected: 2334, got: 2344
There have been errors!
I don't understand why it is failing as when I compare the 2 packages (having those md5 sums) the content is strictly the same (I used a diff tool but no differences and no new or removed files).
The only thing I can see is that the archive from pbuild is bigger of 10 Bytes than the orginal one I have uploaded:
On my development machine, the file with the md5 97257ae2c5790b84ed7bb1b412f1d518 :
-rw-r--r-- 1 zedtux zedtux 2334 Feb 3 23:38 douane-testing_0.8.1-apt1.debian.tar.gz
On my server, the file with the md5 df78f88b97cadc10bc0a73bf86442838 :
-rw-r--r-- 1 root root 2344 Feb 5 00:58 douane-testing_0.8.1-apt1.debian.tar.gz
I have pbuild version 0.213 on my server.
What could be the reason of this behavior and how can I fix it ?
Edit
I'm suspecting an issue with the GPG key which looks missing and then files aren't signed so md5sum is different.
During the build process I have the following lines:
I: Extracting source
gpgv: Signature made Wed Feb 5 22:04:37 2014 UTC using RSA key ID 9474CF36
gpgv: Can't check signature: public key not found
dpkg-source: warning: failed to verify signature on ./douane-testing_0.8.1-apt1.dsc
Edit 2
I have tried to find the command to create manually the .debian.tar.gz file.
The best I've found is the following:
tar cv debian | gzip --no-name --rsyncable -9 > douane-testing_0.8.1-apt1.debian.tar.gz
I don't get the same result than dpkg-source but I tried the same command on my server (I should at least have the same size) but it's not matching...
Could it be that Debian and Ubuntu aren't compressing the same way ?
Finally after some evenings of research I found the solution on launchpad.net !
Found the solution. By default pbuilder calls dpkg-buildpackage like so:
DEBBUILDOPTS="$DEBBUILDOPTS -rfakeroot"
dpkg-buildpackage -us -uc $DEBBUILDOPTS
That causes dpkg-buildpackage to rebuild the diff.gz and .dsc files. Add a -b in there, and it won't. It also means the resulting .changes file will only reference the .deb file. Which is what you want, I think.
The easy solution is to add a line to your .pbuilderrc:
DEBBUILDOPTS="-b"
My previous answer is alright but is not complete.
Then I had the issue that reprepro complains about the source tarball (.orig.tar.xz).
But it was normal as I wasn't doing the packages correctly.
I have written a bash script which I'm executing in VM for each Ubuntu series.
This script was always doing everything from scratch, and was using dh_make --createorig argument and here is the issue.
The correct way is to generate once (for example on Ubuntu precise) and then re-use the .orig.tar.xz file and no more use the --createorig argument of dh_make.
I hope this could help someone :-)
I have to start by saying that I am very much a programming noob. I do not understand all the compiler options or nuances of the IDE, not by a longshot. But I am trying to teach myself more about native programming languages. (I'm decent with C#, but that is much easier than C as I am discovering.)
Today, I wrote this small program in C. It is a console/command line program. I used Visual Studio 2012 and my development machine alternates between Windows 7 and 8, 64 bit. To start, what I did was create a new VC++ project, and I chose a Blank Project. Then I created a new app.c file. I also created a *.rc file to give the executable some extra properties like "File Version" and "Company Name" when you browse the file properties in Windows Explorer. Then I went to the properties of the project, chose Configuration Properties -> C/C++ -> Code Generation and I changed Runtime Library to "Multi-threaded (/MT) so that I wouldn't have to distribute the msvcr100.dll file along with my executable.
In the app.c file, I placed the following code:
#include <stdio.h>
#include <string.h>
#include <Windows.h>
#include <WtsApi32.h>
#pragma comment(lib, "WtsApi32.lib")
void main(int argc, char *argv[])
{
char *helpMsg = "blah";
char *hostName, *connState = "";
char *addrFamily = "";
HANDLE hHost = NULL;
...stuff and so forth and so on...
}
Then I built/compiled the program, and the executable works just fine on Windows 7, 8, Server 2008R2, Server 2012, all 64 bit. But when I try to run the program on Server 2003 (and I am guessing WinXP, etc., as well,) I am greeted with the Windows dialog box:
"Foo.exe is not a valid Win32 application."
So my question is, is there something obvious/simple that I am missing that will allow this executable to also work on earlier XP/2003/32bit platforms that I am missing? I do not believe that I am using any 64-bit exclusive features in my program. But I figured that since I did choose "Blank Project" instead of "Win32 Console Application" that I may be missing some setting.
Edit: Here is the dumpbin.exe /headers output when run against my exe:
Microsoft (R) COFF/PE Dumper Version 11.00.50727.1
Copyright (C) Microsoft Corporation. All rights reserved.
Dump of file C:\users\me\Release\foo.exe
PE signature found
File Type: EXECUTABLE IMAGE
FILE HEADER VALUES
14C machine (x86)
5 number of sections
50F604BC time date stamp Tue Jan 15 19:39:08 2013
0 file pointer to symbol table
0 number of symbols
E0 size of optional header
102 characteristics
Executable
32 bit word machine
OPTIONAL HEADER VALUES
10B magic # (PE32)
11.00 linker version
7800 size of code
A200 size of initialized data
0 size of uninitialized data
16A7 entry point (004016A7) _mainCRTStartup
1000 base of code
9000 base of data
400000 image base (00400000 to 00414FFF)
1000 section alignment
200 file alignment
6.00 operating system version
0.00 image version
6.00 subsystem version
0 Win32 version
15000 size of image
400 size of headers
0 checksum
3 subsystem (Windows CUI)
8140 DLL characteristics
Dynamic base
NX compatible
Terminal Server Aware
100000 size of stack reserve
1000 size of stack commit
100000 size of heap reserve
1000 size of heap commit
0 loader flags
10 number of directories
0 [ 0] RVA [size] of Export Directory
D374 [ 3C] RVA [size] of Import Directory
11000 [ 538] RVA [size] of Resource Directory
0 [ 0] RVA [size] of Exception Directory
0 [ 0] RVA [size] of Certificates Directory
12000 [ C04] RVA [size] of Base Relocation Directory
9160 [ 38] RVA [size] of Debug Directory
0 [ 0] RVA [size] of Architecture Directory
0 [ 0] RVA [size] of Global Pointer Directory
0 [ 0] RVA [size] of Thread Storage Directory
CF98 [ 40] RVA [size] of Load Configuration Directory
0 [ 0] RVA [size] of Bound Import Directory
9000 [ 118] RVA [size] of Import Address Table Directory
0 [ 0] RVA [size] of Delay Import Directory
0 [ 0] RVA [size] of COM Descriptor Directory
0 [ 0] RVA [size] of Reserved Directory
SECTION HEADER #1
.text name
7670 virtual size
1000 virtual address (00401000 to 0040866F)
7800 size of raw data
400 file pointer to raw data (00000400 to 00007BFF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
60000020 flags
Code
Execute Read
SECTION HEADER #2
.rdata name
49E2 virtual size
9000 virtual address (00409000 to 0040D9E1)
4A00 size of raw data
7C00 file pointer to raw data (00007C00 to 0000C5FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
40000040 flags
Initialized Data
Read Only
Debug Directories
Time Type Size RVA Pointer
-------- ------ -------- -------- --------
50F604BC cv 61 0000CFE0 BBE0 Format: RSDS, {582D0FF2-59C1-4633-AF2A-E4A4AD6BFA2C}, 1, C:\Users\me\Release\users.pdb
50F604BC feat 10 0000D044 BC44 Counts: Pre-VC++ 11.00=0, C/C++=116, /GS=116, /sdl=0
SECTION HEADER #3
.data name
2C04 virtual size
E000 virtual address (0040E000 to 00410C03)
E00 size of raw data
C600 file pointer to raw data (0000C600 to 0000D3FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
C0000040 flags
Initialized Data
Read Write
SECTION HEADER #4
.rsrc name
538 virtual size
11000 virtual address (00411000 to 00411537)
600 size of raw data
D400 file pointer to raw data (0000D400 to 0000D9FF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
40000040 flags
Initialized Data
Read Only
SECTION HEADER #5
.reloc name
235C virtual size
12000 virtual address (00412000 to 0041435B)
2400 size of raw data
DA00 file pointer to raw data (0000DA00 to 0000FDFF)
0 file pointer to relocation table
0 file pointer to line numbers
0 number of relocations
0 number of line numbers
42000040 flags
Initialized Data
Discardable
Read Only
Summary
3000 .data
5000 .rdata
3000 .reloc
1000 .rsrc
8000 .text
I have also tried going to Project Properties -> Linker -> System: Minimum Required Version and changing that to 5.00 and 1.00 or whatever, but it has no effect. dumpbin.exe still reports the OS version as 6.00. I have even used editbin.exe /version 5.00 on the exe and no errors were reported... and yet dumpbin.exe still reports 6.00 for the OS version.
VS2012 originally shipped without supporting XP/2003. The updated CRT and runtime support libraries are using too many Windows api functions that are not available on those operating systems. This created quite a stir among its customers, to put it mildly, and they re-engineered the libraries to dynamically bind to these functions and limp along it they are missing. This was made available in Update 1, you'll need to use Project + Properties, General, Platform Toolset = v110_xp to build programs that use those libraries.
Note how it changes a linker setting, the important one, Linker > System > Minimum Required Version = "5.01". Which ensures that the executable file is marked to be compatible with the XP sub-system version. You'll also build against SDK version 7.1, the last one that is still compatible with XP.
When you use the default toolset (v110) then you target sub-system 6.00 and SDK version 8. Version 6.00 was the last major kernel revision, started with Vista.
A brief overview of the new api functions being used to give you a (very rough) idea what is missing in the XP version:
FlsAlloc, FlsFree, FlsGetValue, FlsSetValue : safe thread-local storage
InitializeCriticalSectionEx, CreateSemaphoreEx : safety
SetThreadStackGuarantee : stability
CreateThreadPoolTimer, SetThreadPoolTimer, WaitForThreadPoolTimerCallbacks, CloseThreadPoolTimer : cheaper timers
CreateThreadPoolWait, SetThreadPoolWait, CloseThreadPoolWait : cheaper waits?
FlushProcessWriteBuffers, GetCurrentProcessorNumber, GetLogicalProcessorInformation : threading
FreeLibraryWhenCallbackReturns : stability?
CreateSymbolicLink : functionality
InitOnceExecuteOnce : unknown
SetDefaultDllDirectories : unknown
EnumLocalesEx, CompareStringEx, GetDateFormatEx, GetLocalInfoEx, GetTimeFormatEx, GetUserDefaultLocaleName, IsValidLocaleName, LCMapStringEx : better locale support
I figured it out myself. (But thank you Hans for steering me in the right direction.) For some reason, even with Update 1 and even after setting my toolset to v110_xp, and setting the minimum required version to 5.01 in the Linker options, the resulting dumpbin app.exe /headers still reports a minimum operating system version of 6.0.
So I simply ran
editbin.exe app.exe /SUBSYSTEM:CONSOLE,5.01 /OSVERSION:5.1
And the executable now runs just fine on older operating systems. I'm thinking there still might be a little bit of a bug somewhere in Visual Studio.
The MSVC Team Blog says that when using MSBuild or DEVENV from the command-line with the v110_xp platform toolset, no other changes are necessary. This information is incorrect/incomplete. The /SUBSYSTEM linker argument and associated "Minimum Required Version" must also be set appropriately.
The MSDN documentation for /ENTRY states that, if the /SUBSYSTEM argument is not specified that the SUBSYSTEM and ENTRY POINT are determined automatically. My hunch is that when this happens, the SUBSYSTEM's "Minimum Required Version" argument is also automatically overridden.
The v110_xp toolset automatically specifies the SUBSYSTEM's MRV ("5.1" (WindowsXP)) but not the SUBSYSTEM. As such, the MRV will be overridden, for example, by the linker to "6.0". Running the application will then cause WindowsXP to show the error message stating that the application "is not a valid Win32 application."
I am developing an android app. My requirement is that to implement an rtsp streaming server on android. It has to live stream video and audio captured using MediaRecorder. Another requirement is that I have to use live555 as the streaming server. What I get from MediaRecorder is in MP4 or 3GP format. live555 cannot able to stream both. But it can stream audio if I recorded it only in 'RAW_AMR' format. Since live555 support 'mpg' format for streaming, I decided to put someone in middle who can convert 'mp4' or '3gp' to 'mpg', and I chose ffmpeg.
I have ported live555 and ffmpeg to android. ffmpeg is able to convert the file recorded by MediaRecorder once it is finished. But the problem is that ffmpeg cannot be able to do it concurrently. That is, ffmpeg is not able to convert the file while recording. It shows an Operation not permitted error. I tried the same on my linux machine, using VLC to record instead of MediaRecorder on android. The result is same. ffmpeg is able to convert once the recording is finished, and not able to do the same while recording.
Here is the ffmpeg command I issued on my linux box:
ffmpeg -v 9 -loglevel 99 -i test.mp4 test.mpg
Where test.mp4 is the file to which VLC is recording in mp4 format. and test.mpg is my destination file. The following is the output by ffmpeg on terminal.
ffmpeg version 0.8.9, Copyright (c) 2000-2011 the FFmpeg developers
built on Feb 1 2012 18:29:27 with gcc 4.6.2 20111027 (Red Hat 4.6.2-1)
configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' --enable-bzlib --enable-libcelt --enable-libdc1394 --enable-libdirac --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
libavutil 51. 9. 1 / 51. 9. 1
libavcodec 53. 8. 0 / 53. 8. 0
libavformat 53. 5. 0 / 53. 5. 0
libavdevice 53. 1. 1 / 53. 1. 1
libavfilter 2. 23. 0 / 2. 23. 0
libswscale 2. 0. 0 / 2. 0. 0
libpostproc 51. 2. 0 / 51. 2. 0
[mov,mp4,m4a,3gp,3g2,mj2 # 0x1672600] Format mov,mp4,m4a,3gp,3g2,mj2 probed with size=2048 and score=100
[mov,mp4,m4a,3gp,3g2,mj2 # 0x1672600] ISO: File Type Major Brand: isom
[mov,mp4,m4a,3gp,3g2,mj2 # 0x1672600] moov atom not found
test.mp4: Operation not permitted
Would anyone please tell me what is causing the problem? Or is the scenario above is possible by ffmpeg. That is, is ffmpeg is able to do the conversion at the same time as that of recording? If it is not possible by ffmpeg, would you please suggest any alternative solutions?
NOTE: I am putting a C tag because if it possible by some tweaking in C on ffmpeg, I am ready to do that(I want the solution that badly). But please provide some pointers to the right direction.
Both 3gp and mp4 formats include moov atom (chunk of data) that is written when the file is finalized. Until then the file is incomplete.
You can use FLV as the "middle" format. Other formats that support live streaming can be used too. Option -re may be helpful to tell encoder to run at the stream rate, if needed.
See also Is it possible to play an output video file from an encoder as it's being encoded?.