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• x264 rate control set

  2 juillet 2015, par chinayin

  I have been learning x264 encode for months. What I need is to control the rate and get an average bitrate. Following is my set, I got an average bitrate but the picture quality is bad, so I need your suggestion or something that can help me learn more about x264.

  Params.rc.i_rc_method = X264_RC_ABR ;
  
  Params.rc.i_bitrate = nBitRate*0.65/1000  ;
  
  Params.rc.i_vbv_buffer_size = nBitRate/1000;
  
  Params.rc.i_vbv_max_bitrate = nBitRate*0.65/1000 ;
  
  Params.rc.f_vbv_buffer_init = 1.0 ;
  
  Params.rc.f_rate_tolerance = 1.0 ;                              
  
  Params.i_fps_num =  ParamIn.dFrameRate*0.6 ;
  
  Params.i_fps_den = 1 ;
  
  Params.i_width = ParamIn.nWidth ;
  
  Params.i_height = ParamIn.nHeight ;

• FFMPEG SCREENSHOT ERROR : No such filter : 'tile' [closed]

  22 mai 2013, par itseasy21

  i have been trying on making multiple screenshots from a video file using ffmpeg and i succeed too in command but the only problem is while executing that i am getting this error :

  No such filter: 'tile'
  
  Error opening filters!

  The command i execute is :

  ffmpeg -ss 00:00:10 -i './tmp/try.avi' -vcodec mjpeg -vframes 1 -vf 'select=not(mod(n\,1000)),scale=320:240,tile=2x3' './tmp/try.jpg'

  any solution for this ????

• How to capture camera devices on Windows using Libav ?

  22 septembre 2011, par Occulta

  Is there any way to capture frames from as many camera types as DirectShow do on Windows platform using Libav ? I need to capture a camera output without using DirectShow filters and I want my application to work with many camera devices types.

  I have searched the Internet about this capability of libav and found that it can be done via libav using special input format "vfwcap". Something like that (don't sure about code correctness - I wrote it by myself) :

  AVFormatParameters formatParams = NULL;
  
  AVInputFormat* pInfmt = NULL;
  
  pInFormatCtx*  pInFormatCtx = NULL;
  
  
  
  av_register_all();
  
  
  
  //formatParams.device = NULL; //this was probably deprecated and then removed
  
  formatParams.channel = 0;
  
  formatParams.standard = "ntsc"; //deprecated too but still available
  
  formatParams.width = 640;
  
  formatParams.height = 480;
  
  formatParams.time_base.num = 1000;
  
  formatParams.time_base.den = 30000; //so we want 30000/1000 = 30 frames per second
  
  formatParams.prealloced_context = 0;
  
  
  
  
  
  pInfmt = av_find_input_format("vfwcap");
  
  if( !pInfmt )
  
  {
  
    fprintf(stderr,"Unknown input format\n");
  
    return -1;
  
  }
  
  
  
  // Open video file (formatParams can be NULL for autodetecting probably)
  
  if (av_open_input_file(&pInFormatCtx, 0, pInfmt, 0, formatParams) < 0)
  
     return -1; // Couldn't open device
  
  
  
  /* Same as video4linux code*/

  So another question is : how many devices are supported by Libav ? All I have found about capture cameras output with libav on windows is advice to use DirectShow for this purpose because libav supports too few devices. Maybe situation has already changed now and it does support enough devices to use it in production applications ?

  If this isn't possible.. Well I hope my question won't be useless and this composed from different sources piece of code will help someone interested in this theme 'coz there are really too few information about it in the whole internet.