[ffmpeg] ffmpeg-2.2 patch for relocation R_X86_64_PC32 against symbol error

ffmpeg-2.2-patch

ffmpeg-2.2 patch for relocation R_X86_64_PC32 against symbol error when compile in x64-bit


Patch Link:

Download: V1.0

Scope of Issue:

When ffmpeg is built for static library and this compiled static library is linked with another dynamic library then the final linking failed with error --

ffmpeg/libavcodec/libavcodec.a(xx_yyyy.o): relocation R_X86_64_PC32 against symbol `ff_xx_yy_zz_qq' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: ld returned 1 exit status

Machine:

x64-bit Linux, Unix, may be windows 64-bit

How to fix:

Use the ffmpeg-2.2.patch in your FFmpeg-n2.2 release source.

How to apply patch:

  1. Copy the downloaded patch to your FFmpeg-n2.2 folder.
  2. Test the patch compatibility with your ffmpeg source by --
patch --dry-run -p1 -i  ffmpeg-2.2.patch
giving this command inside your ffmpeg source folder.
  1. If the test returns no fail patch file then you are good to patch.
  2. Now patch by following command --
patch -p1 -i ffmpeg-2.2.patch
  1. Now enjoy linking with your any other project library !!
Note: I am not in blame for any other issue and any other copyright law , if ffmpeg have any for this. This is only a remedy for the group who suffers from this compilation errors.

[eAskGitHub]Simple C++ console for all github repo release API

eAskGitHub
==========


Simple console for all github repo release API.


What?
-----

It is a c++ application with a binary. It is created to make the life simple for github repository API user. It uses curl.

Feature:
--------


1. It can receive any lenght of response from github.
2. It has it's own simple JSON parser method.
3. It is powerfull tool to know your github release download count.
4. Makefile application.

Prerequisite:
-------------


1. Need libcurl.
2. Need Centos/Linux.
3. Not tested with windows(Hopefully it will work after windows curl library installation).

Roadmap:
--------

1. Implement every API of [GitHub API](https://developer.github.com/v3/repos/releases/).

Use:
----


In console just give command -


./eAskGit

Then just follow the hints available on console or answer the querry.

Test Result:
------------


./eAskGit

Welcome to github metadata fetcher eAskGitHub v1.0 !!
It's a very simple command line app who will try to
fill your all want for github metadata(THE API).


Please enter github username: robelsharma
Please enter your one repository name: videoconference
Your querry Succeeded :)
Project Title:=>  Chat and Video call simultaneously
Creators' Login Name:=>  robelsharma
User Privilege:=>  User
Are you an Admin for this site?:=> No
Create Date:=>  2014-08-09T08:04:29Z
Publish Date:=>  2014-08-09T08:15:36Z
Project Binary:=>  VideoConference-1.0.zip
Uploader Login Name:=>  robelsharma
User Privilege:=>  User
Are you an Admin for this site?:=> No
Binary Package Type:=>  application/zip
---------------------
|Downloaded: 6 times|
---------------------
Create Date:=>  2014-08-11T05:50:48Z
Binary Package updated at:=>  2014-08-11T05:50:54Z
Download Link:=>  https://github.com/robelsharma/VideoConference/releases/download/v1.0/VideoConference-1.0.zip
*****************************************************************

Want to continue ?(y/n):n


Jabsimul with SASL Integration is a benchmarking tool for Jabber/XMPP Servers which have SASL authentication

jabsimul-with-sasl
===========

Jabsimul with SASL Integration is a benchmarking tool for Jabber/XMPP Servers which have SASL authentication.
It also has the support for *starttls*.

Special Note:
---------------------

The SASL and starttls implementation is mine. Other than this project is not mine.

Implementation:
-------------------------

I have implemented the protocol named XEP-0034: SASL Integration.

Extra Feature:
-----------------------

Other then jabsimul benchmark feature it has the extra feature of XMPP SASL authentication. I have enabled the SASL plain mechanism of authentication for xmpp login.

With that now you can have the benchmark of jabsimul with SASL authentication.


As list:

1. Implemented “XMPP TLS” from http://xmpp.org/rfcs/rfc3920.html
2. Implemented “SASL AUTH” from  http://xmpp.org/rfcs/rfc3920.html

Source code is available in here .


Procedure:
-----------------

First start a TCP connection to the XMPP server. Then convert this TCP connection to TLS with *starttls* schema request.
Then select the *SASL* auth mechanism and start the the XMPP communication with TLS. The TLS connection holds when the SASL mechanism complete a successful handshake.


1. Protocol Messaging Details with sequence -


Client:
----------

<stream:stream to="intel.com" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams">

Server:
------------

<stream:stream xmlns:stream='http://etherx.jabber.org/streams' xmlns='jabber:client' id='ojTsAaoSvVKdKfmW' from='intel.com'  version='1.0'>
<stream:features>
  <starttls xmlns="urn:ietf:params:xml:ns:xmpp-tls"><required/></starttls>
  <mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
    <mechanism>PLAIN</mechanism><mechanism>X-OAUTH2</mechanism>
  </mechanisms>
 
</stream:features>

Client:
-------
<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>



Server:
-------
<proceed xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>

Implementation details are available [here](https://developers.google.com/cloud-print/docs/rawxmpp)

How To's:
--------

cd jabsimul/jab_simul/
vi jab_simul.xml


Change *<server>jabber.localhost</server>* to your XMPP server address. Fill the xml file with you necessary configuration.

Compile it:

./configure
make

Now you can execute it:

./jab_simul

[WebRTC] Overview and analysis of webRTC media transmission and security with DTLS-SRTP Part - 1

What is webRTC?

WebRTC is an API definition being drafted by the World Wide Web Consortium to enable browser-to-browser applications for voice calling, video chat, and P2P file sharing without plugins.

In short webRTC make you independent from any messenger type application/plug-in that you need to use for a audio/video call.


Call Mechanism in WebRTC:  


Call Attributes:
  • Signaling (SIP/XMPP/Other)
  • ICE (ICE LITE rfc5245)
  • DTLS
  • SRTP
  • PCMU/OPUS for Audio
  • VP8 for Video
Signaling:

This  attribute is necessary for advertising someones' SDP or ICE-Candidate to remote buddy for a call. This can be done by many IETF standard protocol such as - SIP, XMPP or any other protocol.

ICE:

Lite ice is a must for webRTC. Because lite ice support aggressive nomination of ice candidate selection. Which enable a call more faster then any other call. Because the endpoint doesn't need to wait for all the ICE check completion before sending any media. This enables less handshake and early media technique.

DTLS:

DTLS is a transport layer security over datagram (UDP). Its' basically used for SRTP key and certificate negotiation between 2 clients. It is specified on webRTC standard that the SRTP SDES key that are transmitted over websocket is less secure then DTLS SRTP key negotiation. Because in DTLS negotiation SRTP keying material is collected in the time of negotiation and after a certificate fingerprint verification.     

In webRTC call mechanism with SDP a certain other attribute called a=fingerprint: is negotiated with SDP.

v=0
o=Mozilla-SIPUA-27.0.1 25262 1 IN IP4 0.0.0.0
s=Robel Sharma - firefox
t=0 0
a=ice-ufrag:89560a2d
a=ice-pwd:8d80078c1cb16007ee92a607c8f42006
a=fingerprint:sha-256 28:99:57:E4:CE:6F:C6:E4:A2:21:A6:9E:9C:52:EA:A3:FE:99:01:8C:68:31:8B:C3:83:16:3A:92:37:C8:5B:24
m=audio 52345 UDP/TLS/RTP/SAVPF 109 101


This finger print  attribute contain the sha-256 fingerprint value of a valid certificate. Later this value is used for verification.

[CENTOS] How to take screen shot on Centos 6.x

ISSUE: Screen shot is a necessary part of developers life. So you must know how to take screen shot in any OS. When taking screen shot by "Prnt Scrn" button centos give error like -

There was an error running "gnome-screenshot":
Failed to execute child process "gnome-screenshot" (No such file or directory).

Fix: This issue arise due to gnome util's  unavailability. So just install it by yum as a root -

yum install gnome-utils


and enjoy screening.