Changes between Version 49 and Version 50 of Video_Users_Guide


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Timestamp:
Apr 24, 2012 4:10:48 AM (8 years ago)
Author:
bennylp
Comment:

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  • Video_Users_Guide

    v49 v50  
    5555 
    5656{{{ 
     57... 
     58Using SDL prefix... /Users/pjsip/Desktop/opt 
    5759checking SDL availability..... 1.3.0 
     60Using ffmpeg prefix... /Users/pjsip/Desktop/opt 
    5861checking for pkg-config... no 
    5962checking for python... python pkgconfig.py 
    6063checking ffmpeg packages...  libavformat libavcodec libswscale libavutil 
    6164checking for v4l2_open in -lv4l2... no 
    62 }}} 
    63  
    64 Alternative prefixes for SDL and FFMPEG may be specified with '''{{{--with-sdl}}}''' and '''{{{-with-ffmpeg}}}''' options respectively. This points to the ''{{{prefix}}}'' value that was supplied when building SDL and/or FFMPEG. For example, if {{{libavformat.a}}} is in {{{/usr/local/lib}}}, then the prefix is {{{/usr/local}}}. 
     65... 
     66}}} 
     67 
     68The above output shows the SDL version detected, 1.3.0 in this case, and the ffmpeg packages found (libavformat, libavcodec, etc.). Note that for this particular build, alternative locations (prefixes) are specified for both SDL and ffmpeg with '''{{{--with-sdl}}}''' and '''{{{-with-ffmpeg}}}''' options respectively.  
     69 
     70'''Note on ffmpeg libraries dependencies:''' 
     71 
     72  The ''pkg-config'' tool is used to detect the correct compilation settings and library dependency for the ffmpeg packages. The ''pkg-config'' is not installed by default on Mac, as the output above shows, hence we use the alternate ''pkgconfig.py'' script. You need to have Python installed to run this script of course, and the configure script detects its availability automatically. If Python is not available, you will need to supply the correct CFLAGS and LDFLAGS manually prior to running ''{{{configure}}}'' so that it is able to detect ffmpeg libraries. 
     73 
     74  For example, if ffmpeg was built with x264 and mp3 encoder support, you will need to pass additional "{{{-lx264 -lmp3lame}}}" flags when linking libavformat. With manual checking in the configure script, the {{{AC_CHECK_LIB(avformat)}}} would not be able to detect that it needs to add "{{{-lx264 -lmp3lame}}}" as the dependency, hence you need to put this in the LDFLAGS prior to running configure. 
     75 
    6576 
    6677==== 3. Configuring video support ====