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• crystalhd : Switch to new decode API and remove the insanity

  10 octobre 2016, par Philip Langdale

  crystalhd : Switch to new decode API and remove the insanity
  The new decode API allows for m:n decode patterns, which is what
  
  you need to use this hardware in a sane way. There are so many
  
  situations where 1:1 doesn’t happen naturally that it’s a miracle
  
  I got it working as well as I did.
  With this change, we can throw all of the crazy heuristics and
  
  sleeps(!) out, and things work correctly.
  

  • [DH] Changelog
  • [DH] libavcodec/crystalhd.c
  • [DH] libavcodec/version.h

• pictureBox image dispose exception

  22 octobre 2016, par Dulcia

  I recently wanted to try out AForge.NET as I found it to be quite simple, so I decided to make some simple video playback using Video.FFMPEG namespace from it, so I could put each frame directly on a pictureBox. That alone works well, but I wanted to dispose every image after not being important because it took about 1.5GB memory for no apparent reason. That’s where my problem started. For some reason, it sometimes will just throw this exception (usually when resizing the window). I’m not really sure what it could be caused by. Maybe it’s really a stupid mistake. My guess is that it could be caused by timer, but I could have done a completely different mistake and just cannot see it. This is the exception I keep getting :

      ************** Exception Text **************
  
  System.ArgumentException: Parameter is not valid.
  
     at System.Drawing.Image.get_Width()
  
     at System.Drawing.Image.get_Size()
  
     at System.Windows.Forms.PictureBox.ImageRectangleFromSizeMode(PictureBoxSizeMode mode)
  
     at System.Windows.Forms.PictureBox.OnPaint(PaintEventArgs pe)
  
     at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)
  
     at System.Windows.Forms.Control.WmPaint(Message& m)
  
     at System.Windows.Forms.Control.WndProc(Message& m)
  
     at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
  
     at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
  
     at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

  This is the code (I do realize that public variables are not good, I’m just testing of course) :

  public long i = 0;
  
  public Bitmap img;
  
  public VideoFileReader reader;
  
  public System.Timers.Timer aTimer;
  
  
  
  public void render(object source, ElapsedEventArgs e)
  
  {
  
      if (img != null) img.Dispose();
  
      if (i < reader.FrameCount)
  
      {
  
          img = reader.ReadVideoFrame();
  
          pictureBox1.Image = img;
  
      }
  
      i++;
  
  }
  
  
  
  private void button1_Click(object sender, EventArgs e)
  
  {
  
      reader = new VideoFileReader();
  
      aTimer = new System.Timers.Timer();
  
      reader.Open("d:\\result.avi");
  
      aTimer.Elapsed += new ElapsedEventHandler(render);
  
      aTimer.Interval = reader.FrameRate;
  
      aTimer.Enabled = true;
  
  }

• FFMPEG RTSP stream to MPEG4/H264 file using libx264

  4 décembre 2016, par Phi

  Heyo folks,

  I’m attempting to transcode/remux an RTSP stream in H264 format into a MPEG4 container, containing just the H264 video stream. Basically, webcam output into a MP4 container.

  I can get a poorly coded MP4 produced, using this code :

  // Variables here for demo
  
  AVFormatContext * video_file_output_format = nullptr;
  
  AVFormatContext * rtsp_format_context = nullptr;
  
  AVCodecContext * video_file_codec_context = nullptr;
  
  AVCodecContext * rtsp_vidstream_codec_context = nullptr;
  
  AVPacket packet = {0};
  
  AVStream * video_file_stream = nullptr;
  
  AVCodec * rtsp_decoder_codec = nullptr;
  
  int errorNum = 0, video_stream_index = 0;
  
  std::string outputMP4file = "D:\\somemp4file.mp4";
  
  
  
  // begin
  
  AVDictionary * opts = nullptr;
  
  av_dict_set(&opts, "rtsp_transport", "tcp", 0);
  
  
  
  if ((errorNum = avformat_open_input(&rtsp_format_context, uriANSI.c_str(), NULL, &opts)) < 0) {
  
      errOut << "Connection failed: avformat_open_input failed with error " << errorNum << ":\r\n" << ErrorRead(errorNum);
  
      TacticalAbort();
  
      return;
  
  }
  
  
  
  rtsp_format_context->max_analyze_duration = 50000;
  
  if ((errorNum = avformat_find_stream_info(rtsp_format_context, NULL)) < 0) {
  
      errOut << "Connection failed: avformat_find_stream_info failed with error " << errorNum << ":\r\n" << ErrorRead(errorNum);
  
      TacticalAbort();
  
      return;
  
  }
  
  
  
  video_stream_index = errorNum = av_find_best_stream(rtsp_format_context, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
  
  
  
  if (video_stream_index < 0) {
  
      errOut << "Connection in unexpected state; made a connection, but there was no video stream.\r\n"
  
          "Attempts to find a video stream resulted in error " << errorNum << ": " << ErrorRead(errorNum);
  
      TacticalAbort();
  
      return;
  
  }
  
  
  
  rtsp_vidstream_codec_context = rtsp_format_context->streams[video_stream_index]->codec;
  
  
  
  av_init_packet(&packet);
  
  
  
  if (!(video_file_output_format = av_guess_format(NULL, outputMP4file.c_str(),  NULL))) {
  
      TacticalAbort();
  
      throw std::exception("av_guess_format");
  
  }
  
  
  
  if (!(rtsp_decoder_codec = avcodec_find_decoder(rtsp_vidstream_codec_context->codec_id))) {
  
      errOut << "Connection failed: connected, but avcodec_find_decoder returned null.\r\n"
  
          "Couldn't find codec with an AV_CODEC_ID value of " << rtsp_vidstream_codec_context->codec_id << ".";
  
      TacticalAbort();
  
      return;
  
  }
  
  
  
  video_file_format_context = avformat_alloc_context();
  
  video_file_format_context->oformat = video_file_output_format;
  
  
  
  if (strcpy_s(video_file_format_context->filename, sizeof(video_file_format_context->filename), outputMP4file.c_str())) {
  
      errOut << "Couldn't open video file: strcpy_s failed with error " << errno << ".";
  
      std::string log = errOut.str();
  
      TacticalAbort();
  
      throw std::exception("strcpy_s");
  
  }
  
  
  
  if (!(video_file_encoder_codec = avcodec_find_encoder(video_file_output_format->video_codec))) {
  
      TacticalAbort();
  
      throw std::exception("avcodec_find_encoder");
  
  }
  
  
  
  // MARKER ONE
  
  
  
  if (!outputMP4file.empty() &&
  
      !(video_file_output_format->flags & AVFMT_NOFILE) &&
  
      (errorNum = avio_open2(&video_file_format_context->pb, outputMP4file.c_str(), AVIO_FLAG_WRITE, nullptr, &opts)) < 0) {
  
      errOut << "Couldn't open video file \"" << outputMP4file << "\" for writing : avio_open2 failed with error " << errorNum << ": " << ErrorRead(errorNum);
  
      TacticalAbort();
  
      return;
  
  }
  
  
  
  // Create stream in MP4 file
  
  if (!(video_file_stream = avformat_new_stream(video_file_format_context, video_file_encoder_codec))) {
  
      TacticalAbort();
  
      return;
  
  }
  
  
  
  AVCodecContext * video_file_codec_context = video_file_stream->codec;
  
  
  
  // MARKER TWO
  
  
  
  // error -22/-21 in avio_open2 if this is skipped
  
  if ((errorNum = avcodec_copy_context(video_file_codec_context, rtsp_vidstream_codec_context)) != 0) {
  
      TacticalAbort();
  
      throw std::exception("avcodec_copy_context");
  
  }
  
  
  
  //video_file_codec_context->codec_tag = 0;
  
  
  
  /*
  
  // MARKER 3 - is this not needed? Examples suggest not.
  
  if ((errorNum = avcodec_open2(video_file_codec_context, video_file_encoder_codec, &opts)) < 0)
  
  {
  
      errOut << "Couldn't open video file codec context: avcodec_open2 failed with error " << errorNum << ": " << ErrorRead(errorNum);
  
      std::string log = errOut.str();
  
      TacticalAbort();
  
      throw std::exception("avcodec_open2, video file");
  
  }*/
  
  
  
  //video_file_format_context->flags |= AVFMT_FLAG_GENPTS;
  
  if (video_file_format_context->oformat->flags & AVFMT_GLOBALHEADER)
  
  {
  
      video_file_codec_context->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  }
  
  
  
  if ((errorNum = avformat_write_header(video_file_format_context, &opts)) < 0) {
  
      errOut << "Couldn't open video file: avformat_write_header failed with error " << errorNum << ":\r\n" << ErrorRead(errorNum);
  
      std::string log = errOut.str();
  
      TacticalAbort();
  
      return;
  
  }

  However, there are several issues :

  1. I can’t pass any x264 options to the output file. The output H264 matches the input H264’s profile/level - switching cameras to a different model switches H264 level.
  2. The timing of the output file is off, noticeably.
  3. The duration of the output file is off, massively. A few seconds of footage becomes hours, although playtime doesn’t match. (FWIW, I’m using VLC to play them.)

  Passing x264 options

  If I manually increment PTS per packet, and set DTS equal to PTS, it plays too fast, 2-3 seconds’ worth of footage in one second playtime, and duration is hours long. The footage also blurs past several seconds, about 10 seconds’ footage in a second.

  If I let FFMPEG decide (with or without GENPTS flag), the file has a variable frame rate (probably as expected), but it plays the whole file in an instant and has a long duration too (over forty hours for a few seconds). The duration isn’t "real", as the file plays in an instant.

  At Marker One, I try to set the profile by passing options to avio_open2. The options are simply ignored by libx264. I’ve tried :

  av_dict_set(&opts, "vprofile", "main", 0);
  
  av_dict_set(&opts, "profile", "main", 0); // error, missing '('
  
  // FF_PROFILE_H264_MAIN equals 77, so I also tried
  
  av_dict_set(&opts, "vprofile", "77", 0); 
  
  av_dict_set(&opts, "profile", "77", 0);

  It does seem to read the profile setting, but it doesn’t use them. At Marker Two, I tried to set it after the avio_open2, before avformat_write_header .

  // I tried all 4 av_dict_set from earlier, passing it to avformat_write_header.
  
  // None had any effect, they weren't consumed.
  
  av_opt_set(video_file_codec_context, "profile", "77", 0);
  
  av_opt_set(video_file_codec_context, "profile", "main", 0);
  
  video_file_codec_context->profile = FF_PROFILE_H264_MAIN;
  
  av_opt_set(video_file_codec_context->priv_data, "profile", "77", 0);
  
  av_opt_set(video_file_codec_context->priv_data, "profile", "main", 0);

  Messing with privdata made the program unstable, but I was trying anything at that point.
  I’d like to solve issue 1 with passing settings, since I imagine it’d bottleneck any attempt to solve issues 2 or 3.

  I’ve been fiddling with this for the better part of a month now. I’ve been through dozens of documentation, Q&As, examples. It doesn’t help that quite a few are outdated.

  Any help would be appreciated.

  Cheers