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• Decoding with FFMPEG on Visual Studio 2010

  20 décembre 2018, par user2439801

  I just started using FFMPEG with C++ and try to code an audio decoder then write the decoded audio into a file.

  However i’m not sure about which data to write to the output file. As far as i know from looking at the sample codes it seems to be the AVFrame -> data[0].
  But when i try to print it on the consoles, i get some random numbers that are different each time i run the program. And when i try to write this AVFrame->data[0] into a file i keep getting an error.

  So my question is how can I write the decoded audio after I call the function av_codec_decode_audio4 ?

  Below I attached my code and I pass the argument "C :\02.mp3" which is a path for a valid mp3 file on my PC.

  Thank you for your help.

  // TestFFMPEG.cpp : Audio Decoder
  
  //
  
  
  
  #include "stdafx.h"
  
  
  
  #include <iostream>
  
  #include <fstream>
  
  #include <sstream>
  
  
  
  extern "C" {
  
      #include 
  
      #include 
  
      #include 
  
  
  
  }
  
  
  
  using namespace std;
  
  
  
  
  
  int main(int argc, char* argv[])
  
  {
  
  int audioStream = -1;
  
  
  
  AVCodec         *aCodec;
  
  AVPacket        avPkt;
  
  AVFrame         *decode_frame = avcodec_alloc_frame();
  
  
  
  AVCodecContext  *aCodecCtxt;
  
  AVFormatContext *pFormatCtxt = NULL;
  
  
  
  if(argc != 2) {     // Checking  whether there is enough argument
  
      return -1; 
  
  }
  
  
  
  av_register_all();  //Initialize CODEC
  
  avformat_network_init();
  
  av_init_packet (&amp;avPkt);
  
  
  
  
  
   if (avformat_open_input (&amp;pFormatCtxt, argv[1],NULL,NULL)!= 0 ){ //Opening File
  
       return -2;
  
   }
  
  
  
   if(avformat_find_stream_info (pFormatCtxt,NULL) &lt; 0){ //Get Streams Info 
  
       return -3; 
  
   }
  
  
  
   AVStream *stream = NULL;
  
   //av_read_play (pFormatCtxt); //open streams
  
  
  
  
  
   for (int i = 0;  i &lt; pFormatCtxt->nb_streams ; i++) { //Find Audio Stream
  
       if (pFormatCtxt->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO){
  
           audioStream =i;
  
       }
  
   }
  
  
  
   aCodecCtxt = pFormatCtxt ->streams [audioStream]->codec; // opening decoder   
  
   aCodec = avcodec_find_decoder( pFormatCtxt->streams [audioStream] ->codec->codec_id);
  
  
  
   if (!aCodec) {
  
       return -8;
  
   }
  
  
  
   if (avcodec_open2(aCodecCtxt,aCodec,NULL)!=0) {
  
       return -9; 
  
   } 
  
  
  
  int cnt = 0;
  
  
  
  while(av_read_frame(pFormatCtxt,&amp;avPkt) >= 0 ){
  
  
  
      if (avPkt.stream_index == audioStream){
  
          int check = 0; 
  
          int result = avcodec_decode_audio4 (aCodecCtxt,decode_frame,&amp;check, &amp;avPkt);
  
          cout &lt;&lt; "Decoded : "&lt;&lt; (int) decode_frame->data[0] &lt;&lt;", "&lt;&lt; "Check : " &lt;&lt; check &lt;&lt; ", Format :" &lt;&lt; decode_frame->format &lt;&lt;" " &lt;&lt; decode_frame->linesize[0]&lt;&lt; " "&lt;<cnt return="return" acodec="acodec">id;  
  
  } 
  
  </cnt></sstream></fstream></iostream>

• error while linking with ffmpeg under windows using VC 2010

  15 octobre 2017, par Alienpenguin

  I am writing a project on windows that uses opencv (3.2.0 compiled from sources).

  I am trying to add ffmpeg to my project in order to use it to save a mpeg file ; since compiling ffmpeg-3.3.[34] is quite a cumbersome process on windows (i do not currently have mingw or yasm installed) i decided to give the binary packages a try. (downloaded both dev and shared packages from ffmpeg.zeranoe.com)

  Since there were not differentiated dll for "debug" and "release" mode i put them in a common path that would be picked by both visual studio compiling mode.

  When running my project in "debug" mode everything is fine, while after having compiled the "release" version i get the following error when launching the executable

  The error encountered is : (translated from italian so please bear with some imprecise wording) Impossible to find the entry point ?fastFree@cv@YAXPAX@Z of the procedure in the dll avcodec-57.dll

  Can anyone point me in the right direction ? how come the dll complains about a missing symbol only in "release" mode ? also, the signature of the symbol seems to be related to opencv library, but how on earth is this possible ? since opencv was already in the project and is not interacting with ffmpeg ?

• Working on FFmpeg with VC++ 2010

  18 juillet 2017, par user3743908

  I am trying to use FFmpeg in VC++ 2010 so that i can use ffmpeg in to my VC++ Code , i first Install the FFmpeg in to machine by Help provided by youtube video "FFMPEG build for windows"

  while building the sample code provided by ffmpeg (muxing.c) i got following error’s

  1. error C1189 : #error : missing-D__STDC_FORMAT_MACROS /#define _STDC_FORMAT_MACROS

  2 IntelliSense : #error directive : missing -D__STDC_FORMAT_MACROS / #define __STDC_FORMAT_MACROS
  c :\users----\ffmpeg\ffmpeg\include\libavutil\timestamp.h

  how to resolve this error

  i have already done following

  1.Project—>properties—>Configuration Properties—> VC++ Directories —> include dir add all the header files from ffmpeg folder here

  2. in Configuration Properties—> C/C++—>Command Line—>Additional Options —> add -D__STDC_CONSTANT_MACROS

  any help would be highly appreciate

  Thanks

  regards