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• Studying A Game Wave Disc

  23 novembre 2010, par Multimedia Mike — Game Hacking

  I picked up a used copy of game called Gemz — a rather flagrant Bejeweled clone — for a game console called Game Wave Family Entertainment System. Heard of it ? Neither had I. But the game media is optical, so I had to get it and study it.

  
  
  

  When mounted in Linux (as UDF), the disc is reported to contain 2.8 GB of data, so it has to be a DVD. 810 MB of that is dedicated to the movies/ directory. Multimedia format ? Just plain, boring MPEG files (very YouTube-friendly— here’s the opening animation). Deeper digging reveals some more subdirectories called movies/ that, combined, occupy the lion’s share of the disc space. Additionally, there are several single-frame .m2v files in a directory called iframes/ which are used to encode things like load screens.

  
  
  

  There are more interesting data files including .zbm files for images and fonts, and .zwf files for audio. I suspect that these stand for zipped bitmap and zipped wave file, respectively. They can’t be directly unzipped with ’gunzip’. Some of the numbers at the start of some files lead me to believe they can be easily decompressed with standard zlib facilities.

  Based on the binary files on the Gemz disc, I couldn’t find any data on what CPU this system might use. A little Googling led me to this page at the Video Game Console Library which pegs the brain as a Mediamatics 6811. Some searching for that leads me to a long-discontinued line of hardware from National Semiconductor.

  The Console Library page also mentions that the games were developed using the Lua programming language. Indeed, there are many Lua-related strings in the game’s binaries (’zlib’ also makes an appearance).

• The PTS value of the live streaming package is abnormal

  24 octobre 2022, par watermelon_seven

  I am using the ffmpeg source code to receive the udp network video stream, but there is a problem with this video stream. Occasionally, the audio and video packets dts and pts jump at the same time, that is, from a large value to a difference of dozens of times. Very small value, I want to use a solution to solve this problem in the code, but can't think of it. Hope you can help me, thanks !

  


  The following is a process of writing to the buffer to be decoded after receiving the video packet when I receive the network stream. The decoding is done by the video decoding thread, which is only responsible for receiving the stream and writing the buffer to be decoded.

  


      //read video package&#xA;    if(pAvPacket->stream_index == pThis->m_iVideoStreamIndex)&#xA;    {&#xA;        std::cout&lt;&lt;"Video_Packet_DTS: "&lt;dts&lt;&lt;"   Video_Packet_PTS: "&lt;pts&lt;/Video frame rate assignment&#xA;        if(pThis->m_pVideoTimeBase->num > 0 &amp;&amp; pAvPacket->duration > 0)&#xA;            pThis->m_iVideoFPS = (pThis->m_pVideoTimeBase->den / pThis->m_pVideoTimeBase->num) / pAvPacket->duration;&#xA;&#xA;        if(pThis->m_iDecodeMode == DECODE_MODE_ONLY_CURRENT_COLLECTION)&#xA;            pThis->m_videoDecodeThreadState = THREAD_NEED_STOP;     //stop the thread&#xA;        else&#xA;            pThis->m_videoDecodeThreadState = THREAD_NEED_RUN;      //make the thread run&#xA;&#xA;        if(pThis->m_iMultiMediaType != MULTI_MEDIA_TYPE_FILE&#xA;                &amp;&amp; pAvPacket->flags == AV_PKT_FLAG_KEY)&#xA;        {&#xA;                pThis->m_bIsFindIFrame = YTRUE;&#xA;        }&#xA;&#xA;        VideoFramesCount &#x2B;&#x2B;;&#xA;        pThis->m_iReadVideoPacketCount &#x2B;&#x2B;;&#xA;        if(pThis->m_iDecodeMode != DECODE_MODE_ONLY_CHECK_NET &amp;&amp; pThis->m_iDecodeMode != DECODE_MODE_AUDIO &amp;&amp; pThis->m_bIsFindIFrame)&#xA;            YGlobCircleBufferWrite<avpacket>(pThis->m_videoPacketBuffer, &amp;pAvPacket, 1);&#xA;        else&#xA;            av_packet_unref(pAvPacket);&#xA;        pAvPacket = YNULL;&#xA;    }&#xA;</avpacket>

  


  The following is the information printed when the code is run :

  


  Video_Packet_DTS: 8590470992   Video_Packet_PTS: 8590470992
Video_Packet_DTS: 8590474592   Video_Packet_PTS: 8590474592
Video_Packet_DTS: 8590478192   Video_Packet_PTS: 8590478192
Video_Packet_DTS: 8590481792   Video_Packet_PTS: 8590481792
Video_Packet_DTS: 550800   Video_Packet_PTS: 550800
Video_Packet_DTS: 554400   Video_Packet_PTS: 554400
Video_Packet_DTS: 558000   Video_Packet_PTS: 558000
Video_Packet_DTS: 561600   Video_Packet_PTS: 561600
Video_Packet_DTS: 565200   Video_Packet_PTS: 565200


  


  and the error message is printed :

  


  [h264 @ 04fea380] non-existing PPS 0 referenced
[h264 @ 04fea380] decode_slice_header error
[h264 @ 04fea380] no frame!
[swscaler @ 19b04600] Warning: data is not aligned! This can lead to a speed loss
[mp3float @ 04feadc0] overread, skip -6 enddists: -2 -2
[mpegts @ 04fcbf40] DTS 550800 < 8590481792 out of order
[mp3float @ 04feadc0] overread, skip -7 enddists: -6 -6
[mp3float @ 04feadc0] overread, skip -5 enddists: -2 -2


  


  I am so obsessed with their pts because when I synchronize audio and video, I will use their pts for synchronization. If the pts are too different, the video will be stuck when playing the video. I don't know how to avoid

  


• Picturebox from AForge FFMPEG empty - C#/WinForms

  1er août 2017, par Jake Delson

  I’ve done a ton of research and looked at a lot of questions here but can’t seem to find anything to help me. I should preface I’m very new to C#, Windows Forms, and SO ! I’m a 1st year CompSci student coming from C++ experimenting with my own projects for the summer. I’m trying to display a series of bitmaps from a .avi using the AForge.Video.FFMPEG video file reader.

  It seems to be finding the file, getting its’ data (console prints dimensions, framerate, and codec) and creating the picturebox, but the picturebox comes up blank/empty. I get the bitmap from the frames of a .avi :

  From AForge example code here

  Then I’m trying to display it with a picture box :

  From MS example code here as well

  And here’s my code. Essentially a combination of the two :

      public class Simple : Form
  
  {
  
      Bitmap videoFrame;
  
  
  
      public Simple()
  
      {
  
          try
  
          {
  
              // create instance of video reader
  
              VideoFileReader reader = new VideoFileReader();
  
              // open video file
  
              reader.Open(@"C:\Users\User\Desktop\ScanTest3.AVI");
  
              // check some of its attributes
  
              Console.WriteLine("width:  " + reader.Width);
  
              Console.WriteLine("height: " + reader.Height);
  
              Console.WriteLine("fps:    " + reader.FrameRate);
  
              Console.WriteLine("codec:  " + reader.CodecName);
  
  
  
              PictureBox pictureBox1 = new PictureBox();
  
  
  
              // read 100 video frames out of it
  
              for (int i = 0; i < 100; i++)
  
              {
  
                  videoFrame = reader.ReadVideoFrame();
  
  
  
                  pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
  
                  pictureBox1.ClientSize = new Size(videoFrame.Width, videoFrame.Height);
  
                  pictureBox1.Image = videoFrame;
  
  
  
                  // dispose the frame when it is no longer required
  
                  videoFrame.Dispose();
  
              }
  
  
  
              reader.Close();
  
          }
  
  
  
          catch
  
          {
  
              Console.WriteLine("Nope");
  
          }
  
  
  
      }
  
  }
  
  
  
  class MApplication
  
  {
  
      public static void Main()
  
      {
  
          Application.Run(new Simple());
  
      }
  
  }

  So that’s it pretty much. Just a blank picture box coming up, when it should have the first frame of the video, even though no exception caught (though I’m pretty confident I’m using the try/catch very poorly), and the console printing the correct data for the file :

  width:  720
  
  height: 480
  
  fps:    29
  
  codec:  dvvideo
  
  [swscaler @ 05E10060] Warning: data is not aligned! This can lead to a speedloss

  Though if anyone could tell me what that warning means, that would be great as well, but I’m mainly just lost as to why there’s no picture printing to the screen.

  Thanks !