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• ffmpeg command to is throwing error

  25 février 2013, par Bhargav Shah

  I am new to ffmpeg usage.
  I am trying to merge two video file.
  The below bullets will provide you more details about it.

  1. I-ball usb camera
  2. Screen capture utility named UScreenCapture.

  The below command i am using on DOS.

  ffmpeg -f dshow  -i video="iBall Face2Face Webcam C12.0" -f dshow -i video="UScreenCapture"  -r 25 -vcodec mpeg4 -q 12 -f mpegts test.ts

  This command captures only from Uscreencapture source.

  while grabbing frames from Camera it is giving me an error saying that
  real-time buffer 90% full ! frame dropped !
  real-time buffer 121% full ! frame dropped !

  Can any one provide me the solution for this issue ?

• ffmpeg creating multiple output videos, splitting on gt(scene,x)

  18 janvier 2013, par Ben Halpern

  I want to split one video up into multiple parts based on detecting the first frame of each shot, by select scene in ffmpeg.

  The following entry records the scene frames and creates a photo mosaic out of them. This indicates to me that the select portion is functional, but I want to use this to create many separate videos, each scene it's own video file.

  ffmpeg -i video.mpg -vf select='gt(scene\,0.2331)','scale=320x240,tile=1x100' -frames:v preview.png

  Thank you. I think I am close, and I am open to any solution.

• ffmpeg H264 avi file get frame timestamp ?? UINT64_C errorrs

  28 novembre 2013, par jmlaios

  avi file with h264 codec. I need to open it and extract the timestamp of every frame.

  I tried to do it in opencv but it returns wrong results.

  I have modified the code of the example filtering_video.c that exists in the fffmpeg/doc/examples folder in order to get the timestamp.

  I have the following code but compiling it gives me a strange result about UNIT64_C.
  Searching around I saw that it is a ffmpeg problem.

  So 2 questions :
  1. Does this code look capable of returning and printing the frame timestamp
  2. any solution to the UINT64_C problem ??

  Using ubuntu 11.04 and latest ffmpeg.

  code

  #include 
  
  
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  
  
  static AVFormatContext *fmt_ctx;
  
  static AVCodecContext *dec_ctx;
  
  static int video_stream_index = -1;
  
  
  
  static int open_input_file(const char *filename)
  
  {
  
  int ret;
  
  AVCodec *dec;
  
  
  
  if ((ret = avformat_open_input(&amp;fmt_ctx, filename, NULL, NULL)) &lt; 0)
  
  {
  
      printf("Cannot open input file\n");
  
      return ret;
  
  }
  
  
  
  if ((ret = avformat_find_stream_info(fmt_ctx, NULL)) &lt; 0)
  
  {
  
      printf("Cannot find stream information\n");
  
      return ret;
  
  }
  
  
  
  /* select the video stream */
  
  ret = av_find_best_stream(fmt_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &amp;dec, 0);
  
  if (ret &lt; 0)
  
  {
  
      printf("Cannot find a video stream in the input file\n");
  
      return ret;
  
  }
  
  video_stream_index = ret;
  
  dec_ctx = fmt_ctx->streams[video_stream_index]->codec;
  
  
  
  /* init the video decoder */
  
  if ((ret = avcodec_open2(dec_ctx, dec, NULL)) &lt; 0)
  
  {
  
      printf("Cannot open video decoder\n");
  
      return ret;
  
  }
  
  
  
  return 0;
  
  }
  
  
  
  int main(int argc, char **argv)
  
  {
  
  int ret;
  
  AVPacket packet;
  
  AVFrame frame;
  
  int got_frame;
  
  
  
  if (argc != 2)
  
  {
  
      fprintf(stderr, "Usage: %s file\n", argv[0]);
  
      exit(1);
  
  }
  
  
  
  avcodec_register_all();
  
  av_register_all();
  
  
  
  if ((ret = open_input_file(argv[1])) &lt; 0)
  
      goto end;
  
  
  
  /* read all packets */
  
  while (1)
  
  {
  
      if ((ret = av_read_frame(fmt_ctx, &amp;packet)) &lt; 0)
  
          break;
  
  
  
      if (packet.stream_index == video_stream_index)
  
      {
  
          avcodec_get_frame_defaults(&amp;frame);
  
          got_frame = 0;
  
          ret = avcodec_decode_video2(dec_ctx, &amp;frame, &amp;got_frame, &amp;packet);
  
          if (ret &lt; 0)
  
          {
  
             printf("Error decoding video\n");
  
              break;
  
          }
  
  
  
          if (got_frame)
  
          {
  
              frame.pts = av_frame_get_best_effort_timestamp(&amp;frame);
  
              printf("frame timestamp %ld\n", frame.pts);
  
          }
  
  
  
      }
  
  }
  
      av_free_packet(&amp;packet);
  
  end:
  
  if (dec_ctx)
  
      avcodec_close(dec_ctx);
  
  avformat_close_input(&amp;fmt_ctx);
  
  
  
  exit(0);
  
  }

  compiler errors

  /usr/local/include/libavutil/common.h||In function ‘int32_t    av_clipl_int32_c(int64_t)’:|
  
  /usr/local/include/libavutil/common.h|173|error: ‘UINT64_C’ was not declared in this scope|