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• libx264 encoder video plays too fast

  23 avril 2014, par Nick

  I’m trying to write a program that uses libx264 to encode the video frames. I’ve wrapped this code into a small class (see below). I have frames that are in YUV420 format. libx264 encodes the frames and I save them to a file. I can play the file back in VLC, all of the frames are there, but it plays back at several hundred times the actual frame rate. Currently I am capturing frames at 2.5 FPS, but they play back as if it was recorded at 250 or more FPS. I’ve tried to change the frame rate with no luck.

  I’ve also tried to set

  _param.b_vfr_input = 1

  and then set the time bases appropriately, but that causes my program to crash. Any ideas ? My encode code is shown below. I’ve also included the output of ffprobe -show_frames

  Wrapper Class :

  x264wrapper::x264wrapper(int width, int height, int fps, int timeBaseNum, int timeBaseDen, int vfr)
  
  {
  
      x264_param_default_preset(&_param, "veryfast", "zerolatency");
  
      _param.i_threads = 1;
  
      _param.i_width = width;
  
      _param.i_height = height;
  
      _param.i_fps_num = fps;
  
      _param.i_fps_den = 1;
  
      // Intra refres:
  
      _param.i_keyint_max = fps;
  
      _param.b_intra_refresh = 1;
  
      //Rate control:
  
      _param.rc.i_rc_method = X264_RC_CRF;
  
      //_param.rc.i_rc_method = X264_RC_CQP;
  
      _param.rc.f_rf_constant = 25;
  
      _param.rc.f_rf_constant_max = 35;
  
      //For streaming:
  
      _param.b_repeat_headers = 1;
  
      _param.b_annexb = 1;    
  
      // misc
  
      _param.b_vfr_input = vfr;
  
      _param.i_timebase_num = timeBaseNum; 
  
      _param.i_timebase_den = timeBaseDen;
  
  
  
      _param.i_log_level = X264_LOG_DEBUG;
  
  
  
      _encoder = x264_encoder_open(&_param);
  
  
  
      cout << "Timebase " << _param.i_timebase_num << "/" << _param.i_timebase_den << endl;
  
      cout << "fps " << _param.i_fps_num << "/" << _param.i_fps_den << endl;
  
      _ticks_per_frame = (int64_t)_param.i_timebase_den * _param.i_fps_den / _param.i_timebase_num / _param.i_fps_num;
  
      cout << "ticks_per_frame " << _ticks_per_frame << endl;
  
      int result = x264_picture_alloc(&_pic_in, X264_CSP_I420, width, height);
  
      if (result != 0)
  
      {
  
          cout << "Failed to allocate picture" << endl;
  
          throw(1);
  
      }
  
  
  
      _ofs = new ofstream("output.h264", ofstream::out | ofstream::binary);
  
      _pts = 0;
  
  }
  
  
  
  
  
  x264wrapper::~x264wrapper(void)
  
  {
  
      _ofs->close();
  
  }
  
  
  
  
  
  
  
  void x264wrapper::encode(uint8_t * buf)
  
  {
  
      x264_nal_t* nals;
  
      int i_nals;
  
      convertFromBalserToX264(buf);
  
      _pts += _ticks_per_frame;
  
      _pic_in.i_pts = _pts;
  
      x264_picture_t pic_out;
  
      int frame_size = x264_encoder_encode(_encoder, &nals, &i_nals, &_pic_in, &pic_out);
  
      if (frame_size >= 0)
  
      {
  
          _ofs->write((char*)nals[0].p_payload, frame_size);
  
      }
  
      else
  
      {
  
          cout << "error: x264_encoder_encode failed" << endl;
  
      }
  
  }

  Output of ffprobe -show_frames :

  [FRAME]
  
  media_type=video
  
  key_frame=1
  
  pkt_pts=N/A
  
  pkt_pts_time=N/A
  
  pkt_dts=N/A
  
  pkt_dts_time=N/A
  
  pkt_duration=48000
  
  pkt_duration_time=0.040000
  
  pkt_pos=0
  
  width=1920
  
  height=1080
  
  pix_fmt=yuv420p
  
  sample_aspect_ratio=N/A
  
  pict_type=I
  
  coded_picture_number=0
  
  display_picture_number=0
  
  interlaced_frame=0
  
  top_field_first=0
  
  repeat_pict=0
  
  reference=0
  
  [/FRAME]
  
  [FRAME]
  
  media_type=video
  
  key_frame=0
  
  pkt_pts=N/A
  
  pkt_pts_time=N/A
  
  pkt_dts=N/A
  
  pkt_dts_time=N/A
  
  pkt_duration=N/A
  
  pkt_duration_time=N/A
  
  pkt_pos=54947
  
  width=1920
  
  height=1080
  
  pix_fmt=yuv420p
  
  sample_aspect_ratio=N/A
  
  pict_type=P
  
  coded_picture_number=1
  
  display_picture_number=0
  
  interlaced_frame=0
  
  top_field_first=0
  
  repeat_pict=0
  
  reference=0
  
  [/FRAME]
  
  [FRAME]
  
  media_type=video
  
  key_frame=0
  
  pkt_pts=N/A
  
  pkt_pts_time=N/A
  
  pkt_dts=N/A
  
  pkt_dts_time=N/A
  
  pkt_duration=N/A
  
  pkt_duration_time=N/A
  
  pkt_pos=57899
  
  width=1920
  
  height=1080
  
  pix_fmt=yuv420p
  
  sample_aspect_ratio=N/A
  
  pict_type=P
  
  coded_picture_number=2
  
  display_picture_number=0
  
  interlaced_frame=0
  
  top_field_first=0
  
  repeat_pict=0
  
  reference=0
  
  [/FRAME]

• Revision 104616 : Version 1.2.2 (2017-05-23) - Lorsque deux (ou plus) formulaires ...

  11 juin 2018, par kent1@… — Log

  Version 1.2.2 (2017-05-23)
   Lorsque deux (ou plus) formulaires utilisant mutilang sont dans la même page, l’un des deux perdait la fonctionnalité de numéro de titre, exemple sur la page de rubrique ayant un document, le document perdait cette fonctionnalité.
   remplacer les .find('li.editer_titre_numero,div.editer_titre_numero') par .find('.editer_titre_numero') qui suffisent.
   Passer pour la forme la version de schema en 3 chiffres.

• Revision 103226 : 1.4.1 et 2017

  11 juin 2018, par kent1@… — Log

  1.4.1 et 2017