Recherche avancée

Sur d’autres sites (9885)

• Reading a File while it is being written by FFMPEG

  29 mai 2014, par Haris Tasawar

  As the title suggests, i am in the process of creating a client/server application where the server(PHP) reads a file which is being written on by ffmpeg and then outputs it to the client(JAVA). I have succeeded in writing the server script in php which initiates the ffmpeg and then after a while starts to read the file and concurrently sends it to the JAVA client, the problem is that after a while the client stops to receive any sort of data and then just quits, For example if i have a 5MB file, it would read only 12KB and then it quits. Could someone tell what can be the issue here ? Is it on the server side or on the client side.
  For References i am attaching both the reading of file code in php and the client side code.

  Code For Reading the file while FFMPEG converts the file(PHP) :

  $file = 'D:\\'.$destination;
  
  $fp = @fopen($file, 'r');
  
  //ob_end_clean();  
  
  header('Content-Description: File Transfer');
  
  header('Content-Type: application/octet-stream'); 
  
  header("Cache-control: private");
  
  header('Pragma: private');
  
  header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
  
  header('Content-Length: ' . filesize($file));
  
  
  
  $buffer = 4096;
  
  while(!feof($fp)) {
  
  
  
  usleep(300000);
  
  echo fread($fp, $buffer);
  
  ob_flush();
  
  flush();
  
  
  
  
  
  }
  
  fclose($fp);
  
  exit();

  Code For reading the File transferred by PHP (JAVA) :

  URL u = new URL(streamURL);
  
  
  
                  clientSocket = (HttpURLConnection) u.openConnection();
  
  
  
                  if( clientSocket.getResponseCode() == HttpURLConnection.HTTP_OK ){
  
                  //clientSocket.setReadTimeout(0);
  
                  inRemoteStream = clientSocket.getInputStream();
  
  
  
  
  
                  while (((count = inRemoteStream.read(buf)) != -1)) {
  
                      offset += count;
  
                      System.out.println(offset);
  
                      fileOutputStream.write(buf, 0, count);
  
                      setVideoOffset(offset, contentLength);
  
                  }

  I`ll be very happy if someone can solve this problem for me :) .

• Real-time video render

  21 août 2014, par Max Grigoriev

  We’re staring a new project where we should be able to modify on the fly video - add text, insert image.
  Project is planing to be written in Java.
  I’m a newbie in video processing so I want to understand.
  What is the best and fast solution to modify video and return to client (web browser).
  I can easy do it using ffmpeg but mp4 is not streamable. And I should write it to file first and then return to client - it’s not fast.
  Maybe my question is very abstract but I should to start from somewhere :)

  Thanks

• How to Skip frames while decoding H264 stream ?

  16 septembre 2018, par TTGroup

  I’m using FFMPEG to decode H264 (or H265) RTSP Stream.

  My system have 2 software : Server and Client

  Server: Read frames from RTSP stream --> Forward frames to Client    
  
  Client: Receive frames from Server --> Decode --> Render

  I have implemented and it worked ok, but there is a case make my system work not good. That is when internet from Server - Client is slow, frames can not transfer real-time to Client.

  In present, I deal with this issue by Skip some frames (not send to Client) when the Queue is reached limit of count. The following is my summary code

  //At Server Software (include 2 threads A and B)
  
  //Thread A: Read AVPacket and forward to Client
  
  while(true)
  
  {
  
      AVPacket packet;
  
      av_init_packet(&packet);
  
      packet.size = 0;
  
      packet.data = NULL;
  
      int ret = AVERROR(EAGAIN);
  
      while (AVERROR(EAGAIN) == ret)
  
          ret = av_read_frame(pFormatCtx, &packet);
  
      if(packet.size > 0)
  
      {
  
          if(mySendQueue.count < 120) //limit 120 packet in queue
  
              mySendQueue.Enqueue(packet); ////Thread B will read from this queue, to send packets to Client via TCP socket
  
          else
  
              ;//SkipThisFrame ***: No send
  
      }
  
  }
  
  //Thread B: Send To Client via TCP Socket
  
  While(true)
  
  {
  
      AVPacket packet;
  
      if(mySendQueue.Dequeue(packet))
  
      {
  
          SendPacketToClient(packet);
  
      }
  
  }
  
  
  
  //At Server Software : Receive AVPacket from Server --> Decode --> Render
  
  While(true)
  
  {
  
      AVPacket packet;
  
      AVFrame frame;
  
      ReadPacketFromServer(packet);
  
      if (av_decode_asyn(pCodecCtx, &frame, &frameFinished, &packet) == RS_OK)
  
      {
  
          if (frameFinished)
  
          {
  
              RenderFrame(frame);
  
          }
  
      }           
  
  }
  
  UINT32 __clrcall av_decode_asyn(AVCodecContext *pCodecCtx, AVFrame *frame, int *frameFinished, AVPacket *packet)
  
  {
  
      int ret = -1;
  
      *frameFinished = 0;
  
      if (packet) 
  
      {
  
          ret = avcodec_send_packet(pCodecCtx, packet);
  
          // In particular, we don't expect AVERROR(EAGAIN), because we read all
  
          // decoded frames with avcodec_receive_frame() until done.
  
          if (ret < 0 && ret != AVERROR_EOF)
  
              return RS_NOT_OK;
  
      }
  
  
  
      ret = avcodec_receive_frame(pCodecCtx, frame);
  
      if (ret < 0 && ret != AVERROR(EAGAIN))
  
      {
  
          return RS_NOT_OK;
  
      }
  
      if (ret >= 0)
  
          *frameFinished = 1;
  
  
  
      return RS_OK;
  
  }

  My question is focus in line of code SkipThisFrame ***, this algorithm skip frame continuously, so it maybe make the decoder on Client occur unexpectedly error or Crash ?

  And when skip frame like that, make Client Render frames is not normally ?

  And someone call show me the proper algorithm to skip frames in my case ?

  Thank you very much !