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• undefined reference in ffmpeg (use code blocks)

  6 février 2015, par Yonghao Zhao

  I am currently testing a video encoding program using ffmepg codeblocks.I encountered several undefined reference warning. I have checked on internet and add extern "c" to the headers but it still doesnt work. Please help me check.

  Here is part of the code :

  extern "C" {
  
  
  
  #include "libavcodec/avcodec.h"
  
  #include "libavutil/channel_layout.h"
  
  #include "libavutil/common.h"
  
  #include "libavutil/imgutils.h"
  
  #include "libavutil/mathematics.h"
  
  #include "libavutil/samplefmt.h"
  
  
  
  
  
  }
  
  
  
  #include 
  
  #include "libavutil/opt.h"
  
  
  
  static void video_encode_example(const char *filename, int codec_id)
  
  {
  
  
  
  AVCodec *codec;
  
  AVCodecContext *c= NULL;
  
  int i, ret, x, y, got_output;
  
  FILE *f;
  
  AVFrame *frame;
  
  AVPacket pkt;
  
  uint8_t endcode[] = { 0, 0, 1, 0xb7 };
  
  printf("Encode video file %s\n", filename);
  
  /* find the mpeg1 video encoder */
  
  codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
  if (!codec) {
  
  fprintf(stderr, "Codec not found\n");
  
  exit(1);
  
  }
  
  c = avcodec_alloc_context3(codec);
  
  if (!c) {
  
  fprintf(stderr, "Could not allocate video codec context\n");
  
  exit(1);
  
  }
  
  
  
  int main(int argc, char **argv)
  
  {
  
  avcodec_register_all();
  
  video_encode_example("test.mpg", AV_CODEC_ID_MPEG1VIDEO);
  
  
  
  return 0;
  
  }

  The error given :

  ||=== Build : Debug in ffmepg_video_en (compiler : GNU GCC Compiler) ===|
  obj/Debug/main.o||In function

  video_encode_example':|
codeblocksfile/ffmepg_video_en/main.cpp|36|undefined reference to

  avcodec_find_encoder’|
  codeblocksfile/ffmepg_video_en/main.cpp|41|undefined reference to

  avcodec_alloc_context3'|
codeblocksfile/ffmepg_video_en/main.cpp|63|undefined reference to

  av_opt_set(void*, char const*, char const*, int)’|
  codeblocksfile/ffmepg_video_en/main.cpp|65|undefined reference to

  avcodec_open2'|
codeblocksfile/ffmepg_video_en/main.cpp|74|undefined reference to

  av_frame_alloc’|
  codeblocksfile/ffmepg_video_en/main.cpp|85|undefined reference to

  av_image_alloc(unsigned char**, int*, int, int, AVPixelFormat, int)'|
codeblocksfile/ffmepg_video_en/main.cpp|92|undefined reference to

  av_init_packet’|
  codeblocksfile/ffmepg_video_en/main.cpp|112|undefined reference to

  avcodec_encode_video2'|
codeblocksfile/ffmepg_video_en/main.cpp|120|undefined reference to

  av_free_packet’|
  codeblocksfile/ffmepg_video_en/main.cpp|126|undefined reference to

  avcodec_encode_video2'|
/home/yonghao/codeblocksfile/ffmepg_video_en/main.cpp|134|undefined reference to

  av_free_packet’|
  codeblocksfile/ffmepg_video_en/main.cpp|140|undefined reference to

  avcodec_close'|
codeblocksfile/ffmepg_video_en/main.cpp|141|undefined reference to

  av_free’|
  codeblocksfile/ffmepg_video_en/main.cpp|142|undefined reference to

  av_freep'|
codeblocksfile/ffmepg_video_en/main.cpp|143|undefined reference to

  av_frame_free’|
  obj/Debug/main.o||In function

  main':|
codeblocksfile/ffmepg_video_en/main.cpp|151|undefined reference to

  avcodec_register_all’|
  ||=== Build failed : 16 error(s), 0 warning(s) (0 minute(s), 1 second(s)) ===|

• How can I found FFmpeg Error code's meaning ?

  5 mai 2024, par Birds

  I have an issue using FFMPEG.

  



  avcodec_send_packet() is returning error code -12.

  



  I am trying to find what the meaning of -12 is.

  



  I found this page but I can't understand the calculation for -12 :

  



  How can I find out what this ffmpeg error code means ?

  



  Can anyone help me ?

  



  I'm using DXVA2 for decoding. and avcodec_send_packet() function is return -12 after the 20th frame.

  



  20th frame return

  



  

  



  21st frame return

  



  

  


• Get number of frames in video file using ffprobe in C# code

  11 avril 2014, par theGeekster

  I can successfully read number of framres in test.mp4 using Ffprobe on command prompt with following command :

  >ffprobe -i 'c://test.mp4' -show_frames | find /c 'pict_type'

  But when I try to run 'ffprobe.exe' from C# code with following paramters :

  string params = " -i 'c://test.mp4' -show_frames | find /c 'pict_type'";

  It errors as follows :

  ffprobe version N-59453-gd52882f Copyright (c) 2007-2013 the FFmpeg developers
  
    built on Dec 30 2013 22:07:23 with gcc 4.8.2 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  
    libavutil      52. 59.100 / 52. 59.100
  
    libavcodec     55. 47.100 / 55. 47.100
  
    libavformat    55. 22.101 / 55. 22.101
  
    libavdevice    55.  5.102 / 55.  5.102
  
    libavfilter     4.  0.103 /  4.  0.103
  
    libswscale      2.  5.101 /  2.  5.101
  
    libswresample   0. 17.104 /  0. 17.104
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Argument '|' provided as input filename, but ''c://test.mp4'' was already specified.

  How to fix this for C# ?

  I know there is a workaround using Ffmpeg instead but that way is not clean enough.