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• Undefined Referernce Errors FFMPEG + QT + Ubuntu 12.04.2 LTS

  19 July 2013, by Cits

  i have 2 machines with Ubuntu 12.04.2 LTS (64 mb) and the other is a snow leopard OS.
  In my mac i work with ffmpeg without any trouble but then i try to use ffmpeg in ubuntu and 6700 (!) errors appear:

  error: undefined reference to `av_freep'
  
  error: undefined reference to `av_strstart'
  
  error: undefined reference to `av_freep'
  
  ...

  I use QT 4.8.5 and g++ x86 64b
  I installed ffmpeg following http://ffmpeg.org/trac/ffmpeg/wiki/UbuntuCompilationGuide without errors or warnings.

  My test code is:

  .h

  QT += core gui 
  
  
  
  INCLUDEPATH += \
  
      /usr/local/Include
  
  
  
  LIBS += /usr/local/lib/libavcodec.a
  
  LIBS += /usr/local/lib/libavutil.a
  
  LIBS += /usr/local/lib/libavformat.a
  
  LIBS += /usr/local/lib/libswscale.a
  
  
  
  
  
  SOURCES += main.cpp

  .cpp:

  extern "C"
  
  {
  
  #ifndef __STDC_CONSTANT_MACROS
  
  #  define __STDC_CONSTANT_MACROS
  
  #endif
  
  
  
  #include "libavcodec/avcodec.h"
  
  #include "libavformat/avformat.h"
  
  }
  
  
  
  #include 
  
  
  
  int main()
  
  {
  
      AVFormatContext *pFormatCtx;
  
      av_register_all();
  
  
  
      const char* fil = "/home/cits/Desktop/movFile.mov";
  
  
  
      if(avformat_open_input(&pFormatCtx, fil, NULL, NULL)!=0)
  
      {
  
          return -1; // Couldn't open file
  
      }
  
  
  
      if(avformat_find_stream_info(pFormatCtx, NULL)<0)
  
      {
  
          return -1; // Couldn't find stream information
  
      }
  
  
  
      return 0;
  
  }

  Any ideas??

  Thanks in advance.

• MobileVLC for Iphonesimulator

  4 October 2012, by lvreiny

  I'm trying to build mobilevlc for iphonesimulator. I follow the steps from vlc's wiki:

  $ git clone git://git.videolan.org/MobileVLC.git 
  
  $ cd MobileVLC 
  
  $ ./buildMobileVLC.sh

  It stucked at ffmpeg's configure, no response in terminal.
  Anyone has the same experience? What could be the problem?

  I'm using Mac OSX Lion 10.7.5, Xcode 4.5, and building MobileVLC for Iphonesimulator5.1

• FFmpeg: How do i use this script to concatenate incoming segments

  5 July 2017, by NGage

  I’d like to use this script but i don’t know how it should be applied. I was going to use it for encoding tv-shows and be able to start encoding as i had cut out the first segment.

  According to the ffmpeg-wiki (where i found the script) it says: "Concatenation becomes troublesome, if next clip for concatenation does not exist at the moment, because decoding won’t start until the whole list is read. However, it is possible to refer another list at the end of the current list:"

  Bear in mind that i dont know to much about bash

  #!/bin/bash
  
  
  
  fn_concat_init() {
  
  echo "fn_concat_init"
  
  concat_pls=`mktemp -u -p . concat.XXXXXXXXXX.txt`
  
  concat_pls="${concat_pls#./}"
  
  echo "concat_pls=${concat_pls:?}"
  
  mkfifo "${concat_pls:?}"
  
  echo
  
  }
  
  
  
  fn_concat_feed() {
  
  echo "fn_concat_feed ${1:?}"
  
  {
  
      >&2 echo "removing ${concat_pls:?}"
  
      rm "${concat_pls:?}"
  
      concat_pls=
  
      >&2 fn_concat_init
  
      echo 'ffconcat version 1.0'
  
      echo "file '${1:?}'"
  
      echo "file '${concat_pls:?}'"
  
  } >"${concat_pls:?}"
  
  echo
  
  }
  
  
  
  fn_concat_end() {
  
  echo "fn_concat_end"
  
  {
  
      >&2 echo "removing ${concat_pls:?}"
  
      rm "${concat_pls:?}"
  
      # not writing header.
  
  } >"${concat_pls:?}"
  
  echo
  
  }
  
  
  
  fn_concat_init
  
  
  
  echo "launching ffmpeg ... all.mkv"
  
  timeout 60s ffmpeg -y -re -loglevel warning -i "${concat_pls:?}" -pix_fmt 
  
  yuv422p all.mkv &
  
  
  
  ffplaypid=$!
  
  
  
  
  
  echo "generating some test data..."
  
  i=0; for c in red yellow green blue; do
  
  ffmpeg -loglevel warning -y -f lavfi -i testsrc=s=720x576:r=12:d=4 -pix_fmt 
  
  yuv422p -vf "drawbox=w=50:h=w:t=w:c=${c:?}" test$i.mkv
  
  fn_concat_feed test$i.mkv
  
  ((i++));
  
  echo
  
  done
  
  echo "done"
  
  
  
  fn_concat_end
  
  
  
  wait "${ffplaypid:?}"
  
  
  
  echo "done encoding all.mkv"