{
      Ipp32f tmpMinS,tmpMaxS;

      Ipp32f m_PeakAmpdB;

       ippsMinMax_32f(fileData, sizeSamples, &tmpMinS, &tmpMaxS);

      Ipp32f maxAbsSample = IPP_MAX(fabs(tmpMinS),fabs(tmpMaxS));

      if(maxAbsSample > 0) {

            m_PeakAmpdB = 20.f * log10(maxAbsSample / 32768.f);

      } else {

      m_PeakAmpdB = -91.f;

      }

}

In this code, Amp(dB) = 20 lg(S/N), where S- random signal, N - noise. If S=1 then Amp(dB) = 20 lg(1/N) = -91 – this is silence.

The application ‘ffmpeg’ consist of three executables and 5 libraries. All the sources can be downloaded using the following svn command:

Ø      svn checkout svn://svn.ffmpeg.org/ffmpeg/trunk ffmpeg

 Required patch

One version which I tried ( download: svn checkout svn://svn.ffmpeg.org/ffmpeg/trunk ffmpeg –r 17944)

has a known problem with the sources. If you try to build the code, then you will get a compile time error:

 libswscale/swscale.c:488: error: ‘PIX_FMT_YUV420PLE’ undeclared

The solution is solved by copying the contents of the libswscale directory from .   http://www.ffmpeg.org/releases/ffmpeg-0.5.tar.bz2    (see http://www.ffmpeg.org/download.html)

Please Note, only the libswscale directory should be copied over the top of the existing files.

Build Instructions

Following instructions will help you build ffmpeg under a Linux system assuming that the tar ball from the download is copied to <install_directory>:

 Ø      cd  <install_directory>

 Ø      cd tar xvfz  ffmpeg.tar.gz   #Extract the tar ball to your local directory. You will find a directory tree under the name ffmpeg installed. All the required sources are installed within this tree provided that you are not enabling any additional third party libraries.

 Ø      cd ffmpeg

 Ø      ./configure –help <cr> # to show all the options available to rebuild ffmpeg. For a reference build with gcc there is no need to provide any parameters to configure. However if you would like to enable any third party libraries like ‘libfaad’, ‘libx264’ etc. then you need to add --enable-libfaad --enable-libx264 etc. as parameters to configure. If this is required make sure that you have these sources available on your development environment and that the third party libraries are rebuilt with the selected compiler / compiler options.

 Ø      ./configure <parameters as below>

 Ø      make <cr> #recommended sequence is ‘make clean’ followed by ‘make’. The rebuild will take several minutes (depending on your development environment). Two versions of each executable are produced: ex. ‘ffmpeg’ and ‘ffmpeg_g’. The ‘*_g’ contains the executable with debug information while the ‘*’ is the stripped version. In addition ‘ffplay, ffplay_g, ffserver and ffserver_g’ are produced as executables and libavutil, libavcodec, libavformat, libavdevice and libswscale are rebuilt.

 Icc build:

Depending on what version of icc you are using different configure parameters may be necessary.

 Using icc v10.1.xxx:

 Ø      ./configure cc=icc --extra-cflags=”-xL –O3” --extra-libs=-lsvml <cr> # Without linking in the extra library (libsvml.so) you get several references unresolved.

 Using icc v11.0.xxx:

 Ø      ./configure cc=icc –extra-cflags=”-xSSE3_ATOM –O3” –extra-libs=-lsvml <cr> #  The option –xSSE3_ATOM do require that you run the code on a processor which does support the ‘movbe’ instruction. If you would like to test the code on a processor not supporting the ‘movbe’ instruction you can add the option ‘-minstruction=nomovbe’ in the extra-cflag part of the command line above.
Ø      Make sure that the LD (linker) options do not contain ‘–march=generic’ in the config.mak file. This option causes an error from the compiler.

Using icc v11.1.xxx:

Ø      To avoid a run time erratum following source change is needed:   Open file ./libavcodec/x86/dsputil_mmx.c and on line #2944 insert // before || __ICC > 1100. The line is highlighted below.

Ø      After the change it will look like: #if ARCH_X86_64 || ! ( __ICC) // || __ICC > 1100

Ø      ./configure cc=icc –extra-cflags=”-xSSE3_ATOM –O3” <cr> # This simple configure does work but you get better performance if you also add the ‘--extra-lib=-lsvml’. Additional compiler switches can be used to improve the performance – for example ‘-no-prec-div’, ‘-vec-‘. As the no-prec-div has an effect on the fp calculations please refer to the compiler documentation before it is used. In addition the ‘-xSSE3_ATOM’ switch are no longer requiring a processor with ‘movbe’ support.

 Cross compilation.

It is standard practice to build the library and executables on a development machine and then copy the resultant files to the MOBLIN target.  You can use the option --enable–cross-compile in this case.

Once you have completed the configure stage you can just run the ‘make clean’ followed by ‘make’. You could expect additional warnings produced.

Building ffmpeg with third party libraries:

The application can support 21 different external 3^rd party libraries. Each of those are selected in the configure process by adding the option ‘--enable-<library-name>’.

Below is an example of using some of the different external libraries available:

 Ø      ./configure <other options as above> --enable-libfaac --enable-libfaad --enable-libmp3lame --enable-libtheora --enable-libx264 --enable-libxvid 

The invocation above assumes that you will be using 6 external 3^rd party libraries:

 - libfaac       # for example you can download ‘faac-1.28.tar.gz’ or later version from the web.

 - libfaad       # for example you can download ‘faad2-2.7.tar.gz’ or later version from the web.

 - libmp3lame # for example you can download ‘lame-398-2.tar.gz’ or later version from the web.

 - libtheora    # for example you can download ‘libtheora-1.0.tar.tar’ or later version from the web. Please note that you can not use ICC v 10.1 to rebuild this library due to a compiler issue. This has been fixed with 11.1 version of the compiler.

 - libx264      # for example you can download ‘x264-snapshot-20090117-2245.tar.bz2’ or later version from the web.

 - libxvid      # for example you can download ‘xvidcore-1.2.1.tar.gz’ or later version from the web.

Performance Notes: 

Best option combination for ICC: “-xSSE3_ATOM –O3 –vec- -static –no-prec-div –ansi_alias”. Also make sure you add –extra-libs=-lsvml in your configure invocation.

Two ways of improving the performance of ffmpeg:

1) Use the external 3rd party libraries which are supported – 20+ are available. They are optimized for their specific field. You need to select the suitable library – download the code and build them using the ICC.

2) Use PGO. Here it is important to produce a set of .dyn files for the most common conversion you will be using. The code size improves a bit and the performance also gets a boost provided that you use any of the conversions for which you generated a .dyn file. If you select a totally different conversion you actually could get a slower performance compared to both gcc and icc (general optimized version). For those who are not familiar with the PGO optimization this is a three step procedure:

a. Add the option –prof-gen to the extra-cflags section for the configure generation. Build ffmpeg.

b. Run the resulting binary on your target. Make sure you use representative input files and output formats. You may want to repeat this process several times. For each run you will have a .dyn file generated on the target. Copy these files over to your development system.

c. Now use the options –prof-use and –prof-dir <directory path where you have the .dyn files which you copied in step b> [make sure to remove –prof-gen option]. Generate a new make file with configure and build your ffmpeg. You may see a number of warnings ‘missing .dpi information for <file name.’ This is information only and can be ignored. The finally generated ffmpeg should be both smaller and faster.

Optimization Notice

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice. Notice revision #20110804

Introduction

Build environment

The build instructions below are based on the assumption that the build environment is a Fedora10 installation. 

A copy of the installation disks can be found here. http://fedoraproject.org/get-fedora

It is important that the GCC tools are installed when the Fedora installation is installed.

Cross-development

The clutter libraries  and test environment  are first built on a Fedora installation, and then the resultant executables and libraries can then be copied over to a MOBLIN2 platform.

Virtualisation

The steps below can be undertaken on a virtual machine, the only restriction being that not all virtual machines support video acceleration  

The tests

There are a number of tests that can be used to benchmark the clutter library. The benchmark performance is measured by how many Frames Per Second (FPS) are achieved.

Building the Clutter Libraries

Downloading the sources

The sources for the clutter library can be obtained by using the following command.

In a development directory of your choosing download the sources

   git clone git://git.clutter-project.org/clutter

   git clone git://git.clutter-project.org/clutter-box2d

Progress for each download should be reported similar the following:

$ git clone git://git.clutter-project.org/clutter

Initialized empty Git repository in /home/intel/dv/clutter/clutter/.git/
remote: Counting objects: 25225, done.
remote: Compressing objects: 100% (10261/10261), done.
remote: Total 25225 (delta 20575), reused 18319 (delta 14944)
Receiving objects: 100% (25225/25225), 6.99 MiB | 104 KiB/s, done.
Resolving deltas: 100% (20575/20575), done.

Building the Sources

Directory structure should look similar to this:

             <dev-dir>/clutter/
            <dev-dir>/clutter-box2d

In each of these sub directories build the libraries as follows:

Choosing which compiler

Building with GCC

For our installation, we'll use the environment variable  $PREFIX custom directory so as not to override any existing installation

     export PREFIX=/opt/custom/gcc
    ./autogen.sh --prefix=$PREFIX

Building with ICC

To build the library with the Intel compiler use the following commands

    export CC=icc
    export CXX=icc

   export PREFIX=/opt/custom/icc
  ./autogen.sh --prefix=$PREFIX

Continuing the build

When autogen has completed you should get a message similar to the display below 

  
                                  Clutter    0.9.7
                         ====================
                                  prefix:   /opt/custom/gcc
                                Flavour:   glx/gl
                                 XInput:   no
                          GL headers:   GL/gl.h
                    Image backend:   gdk-pixbuf
                       Target library:   libclutter-glx-0.9.la
               Clutter debug level:   yes
                 COGL debug level:   minimum
                      Compiler flags:   -Wall -Wshadow -Wcast-align -Wno-uninitialized -Wno-strict-aliasing -Wempty-body -Wformat-security -Winit-self
        Build API documentation:   no
  Build manual documentation:   no
         Build introspection data:   auto

Now build the source by calling make

The progress of the make will be reported, the last few lines looking similar to this:

   Making all in tools
     CC    disable-npots.o
     LINK  libdisable-npots-static.la
     LINK  libdisable-npots.la
   Making all in po

Installing the new library

To install the new library call:

make install

Note, depending on the permissions of the installation directory (set with the $PREFIX variable in the previous steps) you may need to do this as root.

Building the tests

The test directory has a number of tests. The README describes the tests as follows 

"The conform/ tests should be non-interactive unit-tests that verify a single feature is behaving as documented. See conform/ADDING_NEW_TESTS for more details.

 The micro-bench/ tests should be focused performance test, ideally testing a single metric. Please never forget that these tests are synthetic and if you are using them then you understand what metric is being tested. They probably don't reflect any real world application loads and the intention is that you use these tests once you have already determined the crux of your problem and need focused feedback that your changes are indeed improving matters. There is no exit status requirements for these tests, but they should give clear feedback as to their performance. If the frame rate is the feedback metric, then the test should forcibly enable FPS debugging.

 The interactive/ tests are any tests who's  status can not be determined without a user looking at some visual output, or providing some manual input etc. This covers most of the original Clutter tests. Ideally some of these tests will be migrated into the conformance/ directory so they can be used in automated nightly tests."

To build the tests, from the top level of the test directory do: 

    make

The build will report:

    Making all in data
    Making all in conform
    Making all in interactive
    Making all in micro-bench
    Making all in tools

Running the tests

Having built the tests, each test can be run from the command line.

Automatic running of  tests.

Many of the tests do not run to completion, but keep running,  The script in the appendix below gives an example of how the tests can be automatically called and killed after a predefined time.

Appendix 1 -  Script to drive test cases

#!/usr/bin/perl
# list of tests TODO: EDIT THESE TO YOUR REQUIREMENTS
@Tests=("test-actors", "test-behave", "test-clip","test-cogl-offscreen","test-cogl-primitives","test-cogl-tex-convert","test-cogl-tex-foreign","test-cogl-tex-getset","test-cogl-tex-polygontest","test-cogl-tex-tile","test-depth","test-layout","test-multistage","test-pixmap","test-project","test-random-text","test-rotate","test-scale","test-script","test-sharder","test-text","test-texture-quality","test-textures","test-threads","test-unproject","test-viewport");

#@Tests=("test-actors", "test-behave");
@Results=();

# for each test run it for 10 seconds
my $Timeout = 10;
## chdir interactive;
my $bStarted = 0;

foreach my $Test (@Tests)
{
    # print "executing $Test\n ";
    eval {
        local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
        alarm $Timeout;
        # system("./$Test --clutter-show-fps > res.$Test.txt");

        # mark end of prev test
        push @Results, "END" if $bStarted;
        push @Results, "TEST:$Test\n-----------------------\n";
        $bStarted = 1;
        open (RUN,"./$Test --clutter-show-fps &|");
        while(<RUN>)
        {
            push @Results, $_;
        }
        alarm 0;
    };
    if ($@)
    {
        die unless $@ eq "alarm\n"; # propagate unexpected errors
        # timed out
        system("killall -9 lt-test-interactive");
     }
}
# mark the end of the last test
push @Results, "END" if $bStarted;

# process the results
my $NumTests = 0;
my $Total = 0;
my $Max = 0;
my $Min = 9999;
my $TestName="";

print "\nName Min Max NumTests Average\n";
foreach my $Line (@Results)
{
    if($Line=~/^TEST:(.*)/)
    {
        # print "IN TEST $Line";
        $TestName= $1;
        chomp $TestName;
        $NumTests = 0;
        $Total = 0;
        $Max = 0;
        $Min = 9999;
    }

    if($Line=~/END/)
    {
        # print "IN END :$Line";
        $Average = 0;
        $Average = $Total/$NumTests if $NumTests > 0;
        print "$TestName $Min $Max $NumTests $Average\n";
    }

    if($Line=~/\*\*\* FPS: (.*) \*\*\*/)
    {
        # print "IN FPS: $Line";
        $NumTests++;
        $Total = $Total + $1;
        $Max = $1 if $1 > $Max;
        $Min = $1 if $1 < $Min;
    }
}

print "exiting ..\n";
 

 Appendix 2 - Essential notes on installing Fedora  

When installing Fedora you must install the Software Development tools.