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• Is there a way to use ffmpeg for RGB to true YUV (not YCbCr) conversion ?

  31 mars 2017, par haidahaida

  As far as I can see in the documentation, all conversions involving YUV actually use YCbCr. There are slight differences though, and I would like to convert to the actual YUV format. Is there any way at all using ffmpeg ? As an afterthought, is there any other way that is as fast as ffmpeg ?

  
  ^{Image source}

• Error finding watermark path using ffmpeg in asp.net application

  27 août 2013, par irfanmcsd

  I am using .net ffmpeg wrapper to post watermark on videos. Posting watermark works fine if i execute ffmpeg command directly but failed to find suitable watermark png file location if command executed via asp.net application.

  here is sample ffmpeg command

  string RootPath = HttpContext.Current.Server.MapPath(HttpContext.Current.Request.ApplicationPath);
  
  _mhandler.FFMPEGPath = RootPath + "/ffmpeg_aug_2013/bin/ffmpeg.exe";
  
  _mhandler.InputPath = RootPath + "/contents/original";
  
  _mhandler.OutputPath = RootPath + "/contents/mp4";
  
  _mhandler.BackgroundProcessing = false;
  
  _mhandler.FileName = "wildlife.wmv";
  
  _mhandler.OutputFileName = "wildlife_ddd";
  
  string presetpath = RootPath + "/ffmpeg_aug_2013/presets/libx264-ipod640.ffpreset";
  
  _mhandler.OutputExtension = ".mp4";
  
  _mhandler.Parameters = "-s 640x380 -b:v 500k -bufsize 500k -b:a 128k -ar 44100 -c:v libx264 -vf \"movie = watermark.png [watermark]; [in][watermark] overlay=main_w-overlay_w-10:main_h-overlay_h-10 [out]\"";
  
  _mhandler.Parameters = _mhandler.Parameters + " -fpre \"" + presetpath + "\"";
  
  VideoInfo info =  _mhandler.Process();

  i tried direct code too

  string _out = "";
  
  Process _process = new Process();
  
  _process.StartInfo.UseShellExecute = false;
  
  _process.StartInfo.RedirectStandardInput = true;
  
  //_process.StartInfo.RedirectStandardOutput = true;
  
  _process.StartInfo.RedirectStandardError = true;
  
  _process.StartInfo.CreateNoWindow = true;
  
  _process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
  
  _process.StartInfo.FileName = _ffmpegpath;
  
  _process.StartInfo.Arguments = cmd;
  
  if (_process.Start())
  
  {             
  
      _process.WaitForExit(ExitProcess);
  
      _out = _process.StandardError.ReadToEnd();
  
      if (!_process.HasExited)
  
        _process.Kill();
  
  
  
      return _out;
  
   }

  ffmpeg error output as

  FFMPEG Output:ffmpeg version N-55753-g88909be Copyright (c) 2000-2013
  the FFmpeg developers built on Aug 24 2013 21:40:51 with gcc 4.7.3
  (GCC) configuration : —enable-gpl —enable-version3
  —disable-w32threads —enable-avisynth —enable-bzlib —enable-fontconfig —enable-frei0r —enable-gnutls —enable-iconv —enable-libass —enable-libbluray —enable-libcaca —enable-libfreetype —enable-libgsm —enable-libilbc —enable-libmodplug —enable-libmp3lame —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libopenjpeg —enable-libopus —enable-librtmp —enable-libschroedinger —enable-libsoxr —enable-libspeex —enable-libtheora —enable-libtwolame —enable-libvo-aacenc —enable-libvo-amrwbenc —enable-libvorbis —enable-libvpx —enable-libx264 —enable-libxavs —enable-libxvid —enable-zlib libavutil 52. 42.100 / 52. 42.100 libavcodec 55. 29.100 / 55. 29.100 libavformat 55. 14.102 / 55. 14.102 libavdevice 55. 3.100
  / 55. 3.100 libavfilter 3. 82.102 / 3. 82.102 libswscale 2. 5.100 / 2.
  5.100 libswresample 0. 17.103 / 0. 17.103 libpostproc 52. 3.100 / 52. 3.100 [asf @ 024c9960] Stream #0 : not enough frames to estimate rate ; consider increasing probesize Guessed Channel Layout for Input Stream

  0.0 : stereo Input #0, asf, from 'F :\own\mhp_new/contents/original\wildlife.wmv' : Metadata :

  SfOriginalFPS : 299700 WMFSDKVersion : 11.0.6001.7000 WMFSDKNeeded :
  0.0.0.0000 comment : Footage : Small World Productions, Inc ; Tourism New Zealand | Producer : Gary F. Spradling | Music : Steve Ball title :
  Wildlife in HD copyright : © 2008 Microsoft Corporation IsVBR : 0
  DeviceConformanceTemplate : AP@L3 Duration : 00:00:30.09, start :
  0.000000, bitrate : 6977 kb/s Stream #0:0(eng) : Audio : wmav2 (a1[0][0] / 0x0161), 44100 Hz, stereo, fltp, 192 kb/s Stream

  0:1(eng) : Video : vc1 (Advanced) (WVC1 / 0x31435657), yuv420p, 1280x720, 5942 kb/s, 29.97 tbr, 1k tbn, 1k tbc [image2 @ 024c76e0]

  Could find no file with path 'watermark.png' and index in the range
  0-4 [Parsed_movie_0 @ 024c0540] Failed to avformat_open_input
  'watermark.png' [AVFilterGraph @ 024ca100] Error initializing filter
  'movie' with args 'watermark.png' Error opening filters ! Error Code= 0

  Error on point ( Could find no file with path 'watermark.png' ) shows watermark.png file not found.
  I place watermark.png file in the following locations but still can't found

  i : application root

  ii : root where actual aspx page located

  iii : ffmpeg root

  iv : ffmpeg/bin/

  I also used complete path but still can't detected.

  Note : if i use same ffmpeg command in php and place watermark.png on location where actual php page exist watermark properly detected and command executed properly, but same approach not working in asp.net

  Can any one help me where should i place watermark.png file so that script can access it.

• RTP lipsync synchronization

  18 mai 2017, par Pawel K

  Hi could someone please explain to me how to achieve a lipsync between two RTP streams (from the same RTSP session). I’m trying to calculate proper pts for ffmpeg AVPacket but I’m missing something and I can’t get my head around this.
  I have the following data available to me :
  u64RTCP_NTP_TS - NTP timestamp from RTCP Sender Report
  u32RTCP_TS - Timestamp from the RTCP Sender Report
  u32AudioRTP_TS - Timestamp from the Audio RTP packet
  u32VideoRTP_TS - Timestamp from the Video RTP Packet

  I’ve searched for an answer but still I can’t get a clear picture of how this should be achieved calculation-wise, what am I still missing.