Recherche avancée

Sur d’autres sites (4503)

• Encoded images into H264 video are skipped and/or missing ?

  25 juillet 2013, par Jona

  I'm trying to encode images into an H264 MP4 video. The issues I'm having is that some of the images are skipped or at the end of the video simply missing. I need the video to play every single image I encode since it is an animation.

  Any help setting the encoder properly would be greatly appreciated !

  Encoder settings :

  AVCodecContext *c;
  
  ...
  
  c->codec_id = AV_CODEC_ID_H264;
  
  c->bit_rate = mOutputWidth*mOutputHeight*4;//400000;
  
  /* Resolution must be a multiple of two. */
  
  c->width    = mOutputWidth;
  
  c->height   = mOutputHeight;
  
      /* timebase: This is the fundamental unit of time (in seconds) in terms
  
       * of which frame timestamps are represented. For fixed-fps content,
  
       * timebase should be 1/framerate and timestamp increments should be
  
       * identical to 1. */
  
  c->time_base.den = mFps;
  
  c->time_base.num = 1;
  
  c->gop_size      = 12; /* emit one intra frame every twelve frames at most */
  
  c->pix_fmt       = AV_PIX_FMT_YUV420P;
  
  ...
  
  av_dict_set(&pOptions, "preset", "medium", 0);
  
  av_dict_set(&pOptions, "tune", "animation", 0);
  
  
  
  /* open the codec */
  
  ret = avcodec_open2(c, codec, &pOptions);
  
  if (ret < 0) {
  
      LOGE("Could not open video codec: %s", av_err2str(ret));
  
      return -1;
  
  }

  Update 07/24/13 :
  I was able to achieve a better video by setting the gop_size=FPS and writing the last video frame repeatedly FPS+1 times seemed to resolve all issues. To me it seems odd to do that but might be something standard in the video encoding world ? Any tips feedback about this ?

• Revision 751d002f2f : Adjust rate allocation in non-RD coding mode This commit reduces the frequency

  1er avril 2014, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_pickmode.c

  
   Modify /vp9/encoder/vp9_ratectrl.c

  
   Modify /vp9/encoder/vp9_speed_features.c

  
   Modify /vp9/encoder/vp9_speed_features.h

  
  
  Adjust rate allocation in non-RD coding mode

  This commit reduces the frequency of frames using finer quantizer
  in non-RD coding flow, and slightly tune up the quantizer resolution
  when used. It provides 1.7% compression gains in speed -5 at no speed
  difference.

  Change-Id : I430249a51260a841a0402666e5ec1566e4f7d5a6

• FFMPEG from VB.NET is Not Working

  5 septembre 2013, par Qwerty

  I thought I would make a quick, non-lag screen recorder for Minecraft in a few minutes, boy was I wrong ! Can anyone help me with this error ? Eveything works fine but this last line where it compiles the images into a video. I have a FFMPEG.EXE as a resource, and I have it set to always copy, but whenever I run my program and try to compile the video, it gives me an error to the tune of "unable to find a suitable output format for ffmpeg." Any ideas are awesome ! Thanks !

  Dim compiler As String = Application.StartupPath & "\ffmpeg.exe"
  
  Dim compileLoad As String = """" & savePath & "\img%d.jpg" & """"
  
  Dim compileSave As String = """" & savePath & "\a.mpg" & """"
  
  Process.Start(compiler, "ffmpeg -f image2 -i " & compileLoad & " " & compileSave)