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• ffmpeg custom buffer sink filter

  25 novembre 2018, par NadavRub

  Environment

  • Ubuntu 18.04
  • C++
  • ffmpeg 3.4 (git master)
  • ffmpeg is used as a shared lib (InProc) via the C++ API

  Use-case

  • Per this link I am trying to use the ’avfilter_graph_*’ APIs to create ffmpeg graph
  • I would like the graph output to be sent out to my custom code ( part of the hosting application )

  Considered implementations

  • [A] Implement a custom sink filter ( part of libavfilter ) to implement my custom logic
  • [B] Implement a custom sink filter to grab the output samples and send them out to my application ( something similar to DShow SampleGrabber )

  Problem at hand

  With either of the above mentioned approaches the ffmpeg code has to be modified, and this impose an overhead in supporting future ffmpeg releases

  I wonder if there is any straight forward approach for an external ( hosting ) application to grab the graph output w/ minimal copying of the payload.

  Is there any way to use a custom AVIOContext to achieve that ? can I construct a graph connected to an output AVIOContext ? can I create a custom filter implemented in a module external to libavfilter and associate it w/ the graph using ’AVFilterContext’ ?

• Anomalie #2019 (Nouveau) : forum des rubriques, en partie privée

  4 avril 2011, par jluc -

  Les rubriques sont des objets rédactionnels dont le texte est sujet à amélioration, discussion, validation collective, pourtant il n’y a pas de forums dans la partie privée pour en discuter le contenu. Là par exemple, impossible de commenter le texte de (...)

• LNK 2019 unresolved symbol - FFmpeg

  7 juin 2013, par Cristina1986

  I'm trying to use FFmpeg to open and read a video .avi
  I work on win7 x64 with Visual Studio 2010

  For now my code is very simple :

  #include "libavcodec/avcodec.h"
  
  #include "libavformat/avformat.h"
  
  #include "SDL.h"
  
  #include "SDL_mixer.h"
  
  
  
  
  
  int main (int argc, char *argv[]) {
  
  
  
  AVFormatContext *pFile_video;
  
  int             s, videoStream;
  
  AVCodecContext  *pCodecCtx;
  
  AVCodec         *pCodec;
  
  AVFrame         *pFrame; 
  
  AVFrame         *pFrameRGB;
  
  AVPacket        packet;
  
  int             frameFinished;
  
  int             numBytes;
  
  uint8_t         *buffer;
  
  
  
  av_register_all();
  
  
  
      if((avformat_open_input(&pFile_video, "AR.avi", NULL,NULL)!=0)) cout <<"cannot open video file"</if(av_find_stream_info(pFile_video) <0) cout <<"cannot retrive stream information"<nb_streams;s++){
  
          if((pFile_video->streams[s]->codec->codec_type) == AVMEDIA_TYPE_VIDEO) videoStream =s;
  
      }
  
      if(videoStream ==-1) cout <<"cannot open video stream"<code>

  I linked following .lib files :

  avcodec.lib
  
  avdevice.lib
  
  avfilter.lib
  
  avformat.lib
  
  avutil.lib
  
  postproc.lib
  
  swresample.lib
  
  swscale.lib

  but I get these errors :

  >MSVCRTD.lib(cinitexe.obj) : warning LNK4098: la libreria predefinita 'msvcrt.lib' è in conflitto con l'utilizzo di altre librerie; utilizzare /NODEFAULTLIB:libreria
  
  1>main_video_ffmpeg.obj : error LNK2019: riferimento al simbolo esterno "int __cdecl avformat_open_input(struct AVFormatContext * *,char const *,struct AVInputFormat *,struct AVDictionary * *)" (?avformat_open_input@@YAHPAPAUAVFormatContext@@PBDPAUAVInputFormat@@PAPAUAVDictionary@@@Z) non risolto nella funzione _SDL_main
  
  1>main_video_ffmpeg.obj : error LNK2019: riferimento al simbolo esterno "void __cdecl av_register_all(void)" (?av_register_all@@YAXXZ) non risolto nella funzione _SDL_main
  
  1>C:\Users\Cristina\Desktop\OpenCV\Progetti\MIEI_PROGETTI_Vs\video_ffmpeg\Debug\video_ffmpeg.exe : fatal error LNK1120: 2 esterni non risolti

  I think it is a linker error.. but I haven't other .lib file for FFmpeg library.