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• Memory Leak in c++/cli application

  10 décembre 2013, par Ankush

  I am passing bitmap from my c# app to c++/cli dll that add it to video. The problem is program slowly leaking memory. I tried _CrtDumpMemoryLeaks() shows me leak of bitmap & another 40 byte leak but i am disposing bitmap. Can anyone see memory leak, Here is code..

  Flow:

  1) Capture screenshot by takescreenshot()

  2) pass it to c++/cli function

  3) dispose bitmap

  lines from my c# app

  Bitmap snap = takescreeshot();
  vencoder.AddBitmap(snap);
  snap.Dispose();
  vencoder.printleak();
  
  private static Bitmap takescreeshot()
      {
          System.Drawing.Bitmap bitmap = null;
          System.Drawing.Graphics graphics = null;
  
          bitmap = new Bitmap
          (
              System.Windows.Forms.Screen.PrimaryScreen.Bounds.Width,
              System.Windows.Forms.Screen.PrimaryScreen.Bounds.Height,
              System.Drawing.Imaging.PixelFormat.Format24bppRgb
          );
  
          graphics = System.Drawing.Graphics.FromImage(bitmap);
  
          graphics.CopyFromScreen(Screen.PrimaryScreen.Bounds.X, Screen.PrimaryScreen.Bounds.Y, 0, 0, Screen.PrimaryScreen.Bounds.Size);
  
          //Write TimeSpamp
          Rectangle rect = new Rectangle(1166, 738, 200, 20);
          String datetime= System.String.Format("{0:dd:MM:yy  hh:mm:ss}",DateTime.Now);
          System.Drawing.Font sysfont = new System.Drawing.Font("Times New Roman", 14, FontStyle.Bold);
          graphics.DrawString(datetime, sysfont, Brushes.Red,rect);
          //
  
          Grayscale filter = new Grayscale(0.2125, 0.7154, 0.0721);
          Bitmap grayImage = filter.Apply(bitmap);
  
          //Dispose
          bitmap.Dispose();
          graphics.Dispose();
  
          return grayImage;
      }
  

  now in c++/cli dll

  bool VideoEncoder::AddBitmap(Bitmap^ bitmap)
      {
          BitmapData^ bitmapData = bitmap->LockBits( System::Drawing::Rectangle( 0, 0,bitmap->Width, bitmap->Height ),ImageLockMode::ReadOnly,PixelFormat::Format8bppIndexed);
          uint8_t* ptr = reinterpret_cast( static_cast( bitmapData->Scan0 ) );
          uint8_t* srcData[4] = { ptr, NULL, NULL, NULL };
          int srcLinesize[4] = { bitmapData->Stride, 0, 0, 0 };
  
          pCurrentPicture = CreateFFmpegPicture(pVideoStream->codec->pix_fmt, pVideoStream->codec->width, pVideoStream->codec->height);
  
          sws_scale(pImgConvertCtx, srcData, srcLinesize, 0, bitmap->Height, pCurrentPicture->data, pCurrentPicture->linesize );
  
          bitmap->UnlockBits( bitmapData );
  
          write_video_frame();
  
          bitmapData=nullptr;
          ptr=NULL;
  
          return true;
      }
  
  AVFrame * VideoEncoder::CreateFFmpegPicture(int pix_fmt, int nWidth, int nHeight)
      {
  
        AVFrame *picture     = NULL;
        uint8_t *picture_buf = NULL;
        int size;
  
        picture = avcodec_alloc_frame();
        if ( !picture)
        {
          printf("Cannot create frame\n");
          return NULL;
        }
  
        size = avpicture_get_size((AVPixelFormat)pix_fmt, nWidth, nHeight);
  
        picture_buf = (uint8_t *) av_malloc(size);
  
        if (!picture_buf) 
        {
          av_free(picture);
          printf("Cannot allocate buffer\n");
          return NULL;
        }
  
        avpicture_fill((AVPicture *)picture, picture_buf,
          (AVPixelFormat)pix_fmt, nWidth, nHeight);
  
        return picture;
      }
  
      void VideoEncoder::write_video_frame()
      {
          AVCodecContext* codecContext = pVideoStream->codec;
  
          int out_size, ret = 0;
  
          if ( pFormatContext->oformat->flags & AVFMT_RAWPICTURE )
          {
              printf( "raw picture must be written" );
          }
          else
          {
              out_size = avcodec_encode_video( codecContext, pVideoEncodeBuffer,nSizeVideoEncodeBuffer, pCurrentPicture );
  
              if ( out_size > 0 )
              {
                  AVPacket packet;
                  av_init_packet( &packet );
  
                  if ( codecContext->coded_frame->pts != AV_NOPTS_VALUE )
                  {
                      packet.pts = av_rescale_q( packet.pts, codecContext->time_base, pVideoStream->time_base );
                  }
  
                  if ( codecContext->coded_frame->pkt_dts != AV_NOPTS_VALUE )
                  {
                      packet.dts = av_rescale_q( packet.dts, codecContext->time_base, pVideoStream->time_base );
                  }
  
                  if ( codecContext->coded_frame->key_frame )
                  {
                      packet.flags |= AV_PKT_FLAG_KEY;
                  }
  
                  packet.stream_index = pVideoStream->index;
                  packet.data = pVideoEncodeBuffer;
                  packet.size = out_size;
  
                  ret = av_interleaved_write_frame( pFormatContext, &packet );
  
                  av_free_packet(&packet);
                  av_freep(pCurrentPicture);
              }
              else
              {
                  // image was buffered
              }
          }
  
          if ( ret != 0 )
          {
              throw gcnew Exception( "Error while writing video frame." );
          }
      }
  
  
      void VideoEncoder::printleak()
      {
          printf("No of leaks: %d",_CrtDumpMemoryLeaks());
          printf("\n");
      }
  

• Command find and and convert using ffmpeg

  10 décembre 2013, par molwiko

  I would like to combine the two following commands to find mp4 files and convert them to mp3 and save them with same name. Thanks in advance. The two command line:

  find ./ -name '*.mp4'
  ffmpeg -i video.mp4 -vn -acodec libmp3lame -ac 2 -ab 160k -ar 48000 audio.mp3
  

• MUXING two media files using in .net

  10 décembre 2013, par Newton Sheikh

  i got two media files xyz.wav(audio) and xyz.webm(video) i want to mux them into a single file xyz.mp4 in c#.

  i google a bit and found this tool for c# http://www.ffmpeg-csharp.com/ but there is no documentation for merging audio and vdo files.

  can u suggest me some way to achieve it or any other library that u have used.

  So far i was using the command line way of doing it using the ffmpeg.exe

  ffmpeg.exe" -i 180523220.wav -i 180523220.webm 1.mp4
  

  but this is not what is required.

• Node.js Webm live stream server : issues with tag

  10 décembre 2013, par breathe0

  I'm using Node.js as stream server to stream realtime Webm videos that is sent by FFMPEG (executed from another application, the stream is done via HTTP) and received by a webapp that uses the tag.

  This is what I'm doing: FFMPEG streams the received frames using the following command:

  ffmpeg -r 30 -f rawvideo  -pix_fmt bgra -s 640x480 
  -i \\.\pipe\STREAM_PIPE -r 60 
  -f segment  -s 240x160 -codec:v libvpx  -f webm 
  http://my.domain.com/video_stream.webm
  

  (the stream comes from an application that uses the Kinect as source and communicates with FFMPEG through a pipe, sending one frame after another)

  When the webapp connects, it receives immediately this response from the server:

  HTTP/1.1 200 OK
  X-Powered-By: Express
  content-type: video/webm
  cache-control: private
  connection: close
  Date: Fri, 06 Dec 2013 14:36:31 GMT
  

  and a Webm header (previously stored on the server, with the same resolution and frame rate of the source stream and tested as working on VLC) is immediately appended. Then the webapp starts to receive the data streamed by FFMPEG. Here is a screenshot of Mkvinfo GUI showing the fields of the header:

  

  However, even if the Network tab of the Chrome console shows that there is an actual stream of data (meaning that what is streamed is not completely garbage, otherwise the connection would be dropped), the player doesn't display anything. We tried to manually prepend our header to the dumped video received by the webapp and VLC plays it just fine, but this is not happening with the tag.

  What can cause this problem? Are we missing something about the encoding on the FFMPEG side or we stored wrong values on the header (or they're not enough)?

  PS: I cannot rely on an extern stream server.

  PPS: We tried the following experiments:

  • substituting the video header with the one stored in the server makes the video playable on both vlc and video tag
  • if we dump the video that is already started (without an header) and we prepend the video header stored in the server or even its original header, the video is playable in VLC but not on the tag (we're carefully prepending the header just before the beggining of the cluster).

• Bash Scripting FFMPEG how to wait the process to complete

  9 décembre 2013, par user1738671

  I have a strange problem. I have a folder monitor with incrontab that launches an automatic transcoding script on CLOSE_WRITE state of a file I dropped in. The problem is that the script doesn't wait until the ffmpeg process finishes before continuing with the rest of the script commands. This means that the original file get deleted before the transcoding is finished, which is bad.

  First question: What is the root cause of this behaviour?

  Second question: In a bash script, what is the best way to make sure an ffmpeg process is done before get going with the rest of the script?

  Script:

  #/bin/bash
  
  #transcoding
  /usr/bin/ffmpeg -i "sourcefile push with incron as $1" -vcodec somecode -acodec somecodec "destination file"
  
  #delete source
  rm "path/to/file$1"
  

  Should I encapsulate my FFMPEG in a while statement?