Recherche avancée

Sur d’autres sites (8146)

• error while compiling simple c++ file with libavformat library

  21 février 2023, par Abdo Daood

  i create simple c++ file called test.cpp

  


  #include <iostream>&#xA;#include &#xA;using namespace std;&#xA;&#xA;int main() &#xA;{&#xA;    cout &lt;&lt; "Hello, World!";&#xA;    return 0;&#xA;}&#xA;&#xA;</iostream>

  


  and using g++ in terminal to compile test.cpp file with the command :

  


  


  g++ test.cpp -o test

  


  


  i get this error =>

  


  test.cpp:2:10: fatal error: libavformat\avformat.h: No such file or directory
    2 | #include 
      |          ^~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.


  


  Notes :
libavformat\avformat.h path is : /usr/include/x86_64-linux-gnu/libavformat/avformat.h

  


  and using ffmpeg version is :

  


  $ ffmpeg -version

  


  ffmpeg version 4.4.2-0ubuntu0.22.04.1 Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 11 (Ubuntu 11.2.0-19ubuntu1)
configuration : —prefix=/usr —extra-version=0ubuntu0.22.04.1 —toolchain=hardened —libdir=/usr/lib/x86_64-linux-gnu —incdir=/usr/include/x86_64-linux-gnu —arch=amd64 —enable-gpl —disable-stripping —enable-gnutls —enable-ladspa —enable-libaom —enable-libass —enable-libbluray —enable-libbs2b —enable-libcaca —enable-libcdio —enable-libcodec2 —enable-libdav1d —enable-libflite —enable-libfontconfig —enable-libfreetype —enable-libfribidi —enable-libgme —enable-libgsm —enable-libjack —enable-libmp3lame —enable-libmysofa —enable-libopenjpeg —enable-libopenmpt —enable-libopus —enable-libpulse —enable-librabbitmq —enable-librubberband —enable-libshine —enable-libsnappy —enable-libsoxr —enable-libspeex —enable-libsrt —enable-libssh —enable-libtheora —enable-libtwolame —enable-libvidstab —enable-libvorbis —enable-libvpx —enable-libwebp —enable-libx265 —enable-libxml2 —enable-libxvid —enable-libzimg —enable-libzmq —enable-libzvbi —enable-lv2 —enable-omx —enable-openal —enable-opencl —enable-opengl —enable-sdl2 —enable-pocketsphinx —enable-librsvg —enable-libmfx —enable-libdc1394 —enable-libdrm —enable-libiec61883 —enable-chromaprint —enable-frei0r —enable-libx264 —enable-shared
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100

  


  using this command :

  


  g++ `pkg-config --cflags libavformat` test.cpp  `pkg-config --libs libavformat` -o test



  


• Error : "libavformat\avformat.h : No such file or directory"

  21 février 2023, par Abdo Daood

  I create a simple c++ file called test.cpp :

  


  #include <iostream>&#xA;#include &#xA;using namespace std;&#xA;&#xA;int main() &#xA;{&#xA;    cout &lt;&lt; "Hello, World!";&#xA;    return 0;&#xA;}&#xA;</iostream>

  


  and using g++ in terminal to compile test.cpp file with the command :

  


  g++ test.cpp -o test


  


  I get this error :

  


  test.cpp:2:10: fatal error: libavformat\avformat.h: No such file or directory
    2 | #include 
      |          ^~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.


  


  Notes :
libavformat\avformat.h path is : /usr/include/x86_64-linux-gnu/libavformat/avformat.h

  


  and using ffmpeg version is :

  


  $ ffmpeg -version

ffmpeg version 4.4.2-0ubuntu0.22.04.1 Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 11 (Ubuntu 11.2.0-19ubuntu1)
configuration: --prefix=/usr --extra-version=0ubuntu0.22.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-librsvg --enable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil      56. 70.100 / 56. 70.100
libavcodec     58.134.100 / 58.134.100
libavformat    58. 76.100 / 58. 76.100
libavdevice    58. 13.100 / 58. 13.100
libavfilter     7.110.100 /  7.110.100
libswscale      5.  9.100 /  5.  9.100
libswresample   3.  9.100 /  3.  9.100
libpostproc    55.  9.100 / 55.  9.100


  


  Using this command :

  


  g++ `pkg-config --cflags libavformat` test.cpp  `pkg-config --libs libavformat` -o test


  


• av_read_frame and time stamps C++

  19 avril 2014, par halfwaythru

  I am recording an RTSP H264 stream from an Axis IP camera using libavformat. This camera is supposed to stamp every frame with the time that the frame was acquired, and this information is supposed to be in the RTP packet header.

  This is the code that I am using to read in the frames.

  AVFormatContext *inputFormatCtxt = NULL;
  
  avformat_open_input(&inputFormatCtxt, inputURL, NULL, NULL) 
  
  avformat_find_stream_info(inputFormatCtxt, NULL )
  
  
  
  while(av_read_frame(inputFormatCtxt, &packet) >=0)
  
  {
  
      if(packet.stream_index == videoStreamIndex)
  
      {
  
         // Do something to video packet.
  
      }
  
      else
  
      {
  
         // Do something to audio packet. 
  
      }
  
  
  
      if (packet.pts != AV_NOPTS_VALUE)
  
          packet.dts = packet.pts    = av_rescale_q(packet.pts, stream->time_base, oStream->time_base);
  
      else
  
          NSLog(@"packet.pts == AV_NOPTS_VALUE");
  
  
  
      if(av_interleaved_write_frame(outputFormatCtxt, &packet) < 0)
  
          NSLog(@"Could not write out frame.");
  
  
  
      av_free_packet(&packet);
  
  }

  Now in AVPacket, the only time-related information is the pts and the dts. After converting them into seconds, these are supposed to be the offset of the packet (in seconds) from the start of the stream.

  My question is : How do I get the start time of the stream ?

  These are the many things that I have tried :

  1.) In AVFormatContext there is a variable start_time_realtime that is "supposed" to be the start time of the stream in real world time, in microseconds. This is exactly what I need. But no matter what I do, this value is always 0, and never changes. Am I missing a step in initialization that this never get set ?

  2.) Looking at this link, I added an RTPDemuxContext object to my code :

  RTSPState* rtsp_state = (RTSPState*) inputFormatCtxt->priv_data;
  
  RTSPStream* rtsp_stream = rtsp_state->rtsp_streams[0];
  
  RTPDemuxContext* rtp_demux_context = (RTPDemuxContext*) rtsp_stream->transport_priv;

  When I tried to look at the last_rtcp_reception_time, last_rtcp_ntp_time, last_rtcp_timestamp timestamps within the RTPDemuxContext object, these values are also 0 always, and dont change.

  3.) With the last point, I tried to force fetch a packet using ff_rtsp_fetch_packet(inputFormatCtxt, &packet). This did update the RTPDemuxContext timestamps, but only while stepping through code. If I just ran the code in a loop, it always remained the same as whatever was in the RTDemuxContext object before the loop.

  int64_t x = 0;
  
  x = rtp_demux_context->last_rtcp_reception_time;   // x is 0.
  
  while(ff_rtsp_fetch_packet(inputFormatCtxt, &packet))
  
  {
  
      x = rtp_demux_context->last_rtcp_reception_time;   // x changes only when stepping through code. else remains 0 
  
  }

  At this point I have no idea what I am doing wrong. I cant seem to get this timestamp information, no matter what I try. Any help is much appreciated. Thanks !