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• Can't open encoder when use libavcodec

  1er novembre 2013, par liuyanghejerry

  I’m using libavcodec, version 9.7, to write a simple demo, almost exactly like example in official example.

  However, I can’t open encoder. Also, av_opt_set(context->priv_data, "preset", "slow", 0) always leads to crush.

  This is my code :

  // other code...
  
  int ret = 0;
  
  avcodec_register_all();
  
  AVCodec* codec = NULL;
  
  AVCodecContext* context = NULL;
  
  AVFrame* frame = NULL;
  
  uint8_t endcode[] = { 0, 0, 1, 0xb7 };
  
  codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
  if(!codec){
  
      qDebug()<<"cannot find encoder";
  
      return;
  
  }
  
  qDebug()<<"encoder found";
  
  
  
  context = avcodec_alloc_context3(codec);
  
  if(!context){
  
      qDebug()<<"cannot alloc context";
  
      return;
  
  }
  
  qDebug()<<"context allocted";
  
  
  
  context->bit_rate = 400000;
  
  /* resolution must be a multiple of two */
  
  context->width = 352;
  
  context->height = 288;
  
  /* frames per second */
  
  context->time_base= (AVRational){1,25};
  
  context->gop_size = 10; /* emit one intra frame every ten frames */
  
  context->max_b_frames=1;
  
  context->pix_fmt = AV_PIX_FMT_YUV420P;
  
  qDebug()<<"context init";
  
  
  
  // av_opt_set(context->priv_data, "preset", "slow", 0); // this will crush
  
  AVDictionary *d = NULL;
  
  av_dict_set(&d, "preset", "ultrafast",0); // this won't
  
  
  
  ret = avcodec_open2(context, codec, &d);
  
  if ( ret < 0) {
  
      qDebug()<<"cannot open codec"</ other code...

  This outputs :

  encoder found

  context allocted

  context init

  cannot open codec -22

  [libx264 @ 0340B340] [IMGUTILS @ 0028FC34] Picture size 0x10 is invalid

  [libx264 @ 0340B340] ignoring invalid width/height values

  [libx264 @ 0340B340] Specified pix_fmt is not supported

  I don’t think the width/height is invalid and format there either. I have no idea what’s wrong here.

  Any help. plz ?

• ffmpeg/opencv How to perform Edge Detection after classify Type of frames

  25 janvier 2018, par 8793

  I want to generate edge map of I-frame only in a video streaming applications (server). Below is code to generate type of frame in ffmpeg.

  AVFrame *frame; 
  
  pictType = av_get_picture_type_char(frame->pict_type);

  After this step, I don’t know how to process frame (using opencv c++) to have its edge map.

  As I am a beginner in ffmpeg, I hope you can give me a simple example to understand this issue.

• Kill all ffmpeg processes which open repeatedly c#

  20 janvier 2018, par MinhLee

  i’m new to C# and i’m trying to create a tool based on ffmpeg to convert video.
  As title, i did google search and find out many ways to kill ffmpeg process, but in my case, for example i got 10 videos, which means 10 ffmpeg processes will be created one by one. If i closed form during 1st video, 9 others will be created sequently in background.

  Is there any effective ways to stop ffmpeg to create process ?