FFMPEG未定义参考C中的’avcodoec_open2′

我制作程序时遇到的错误如下：

-------- begin --------
Linking: Analysing_Server
./source/Encoding_Thread.o: In function `CEncoding_Thread::do_work()':
/home/Analyser/source/Encoding_Thread.cpp:155: undefined reference to `avcodec_open2'
collect2: ld returned 1 exit status
make: *** [Analysing_Server] Error 1

我的Make文件的相关行类似于运行g,如下所示：

g++ test2.cpp -lavformat -lavcodec -lavutil -D__STDC_CONSTANT_MACROS

抛出错误的我的相关CPP代码的精简版本是：

#include <stdio.h>
#include <stdint.h> 

#define LOG_OUT_STREAM_BUFF_SIZE  200000


extern "C"  {
  /* The ffmpeg library is completely written in C,so we need to tell the C++ compiler that so it links correctly. */
  #include "stdint.h"
  #include "libavcodec/avcodec.h"
  #include "libavutil/mathematics.h"
  #include "libswscale/swscale.h"
  #include "libavfilter/avfilter.h"

  int avcodec_open2(AVCodecContext *avctx,AVCodec *codec,AVDictionary **options);
  int avcodec_encode_video2(AVCodecContext *avctx,AVPacket *avpkt,const AVFrame *frame,int *got_packet_ptr);
}

uint8_t m_outbuf[2][LOG_OUT_STREAM_BUFF_SIZE];
unsigned int m_out_size[2];
unsigned int m_OutBuffer_ID[2];
unsigned int m_Buffer_ID; /* This is just a uniqueish stamp we give to each buffer so we can tell when they change.. */

AVCodecContext * m_CodecContex;
AVCodec * m_codec;
struct SwsContext *m_img_convert_ctx;

unsigned char* m_DataBuff;

int Output_Width,Output_Height;
int Output_Bitrate;


int main(void) {
  //New version of FFMPEG calls this in avcodec_register_all
  //avcodec_init();

  /* register all the codecs */
  avcodec_register_all();

  /* Initalise the encoder */
  m_codec = avcodec_find_encoder(CODEC_ID_MP2);

  if (!m_codec) {
    printf("Encoding codec not foundn");
  }

  /* init the pointers.. */
  m_CodecContex = NULL;

  /* Default values.. */
  Output_Width = 1600;
  Output_Height = 1200;
  Output_Bitrate = 600000;

  /* Create/setup the Codec details.. */
  //Changed to work with new FFMPEG
  m_CodecContex = avcodec_alloc_context3(m_codec);
  avcodec_get_context_defaults3(m_CodecContex,m_codec);

  /* put sample parameters */
  m_CodecContex->bit_rate = Output_Bitrate;
  /* resolution must be a multiple of two */

  m_CodecContex->width = Output_Width;
  m_CodecContex->height = Output_Height;
  /* frames per second */
  m_CodecContex->time_base= (AVRational){1,25};

  m_CodecContex->gop_size = 10; /* emit one intra frame every ten frames */
  m_CodecContex->max_b_frames=1;
  m_CodecContex->pix_fmt = PIX_FMT_YUV420P; /* must be YUV for encoding.. */


  AVDictionary * RetunedAVDic;

  /* open it */
  //Changed to work with new FFMPEG
  if (avcodec_open2(m_CodecContex,m_codec,&RetunedAVDic) < 0) {
      printf("could not open codec");
  }
}

不幸的是,FFMPEG附带的’doc / examples / decoding_encoding.c’下的示例不再有效,因为它使用的所有函数现在都已折旧.我的代码基于示例代码,并且与FFMPEG 0.8一起工作正常,但不能使用最新版本的FFMPEG进行编译.我已将一些折旧函数更改为较新版本,但仍无法编译.

有谁知道我为什么会收到这个错误？或者有没有人使用最新版本的FFMPEG链接到’doc / examples / decoding_encoding.c’这样的例子？