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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 ?

• the ffmpeg library cannot open camera on android

  27 septembre 2013, par GilGaMesh

  I have successfully ported ffmpeg 2.0.1 lib to android. The code to open camera is very simple :

  AVFormatContext *fmt_ctx = NULL;
  
  AVInputFormat *input_fmt;
  
  
  
  input_fmt = av_find_input_format("video4linux2"); 
  
  if (input_fmt == NULL)
  
      return -1；
  
  
  
  char f_name[] = "/dev/video0";
  
  if ((ret = avformat_open_input(&fmt_ctx, f_name, input_fmt, NULL)) < 0)        // stuck here
  
  {
  
      LOG_D("can not open camera, ret = %d", ret);
  
      return ret;
  
  }

  the strange thing is the ret value is always negative with the following logcat output by av_log :

  09-26 15:27:48.901: E/Codec-FFMpeg(17716): ioctl(VIDIOC_G_PARM): Invalid argument

  I change the f_name to /dev/video1 and /dev/video2 (these files indeed exist on my tablet, and my tablet has 2 cameras) and the problems remains.
  Do i forget anything before calling avformat_open_input() ? Thank you !

• Revision 52513 : Slogan, description, borne sup spip. Traductions (en, es, de) du slogan et ...

  5 octobre 2011, par yffic@… — Log

  Slogan, description, borne sup spip.
  Traductions (en, es, de) du slogan et description à (re)faire