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• FFMPEG Compilation on Windows 32 bit Vs 64 bit

  15 janvier 2016, par ARK

  When I try to compile ffmpeg using MinGW, targeting 32-bit, I observed below error for several files :

  c :\mingw\include\unistd.h:79:1 : error : expected ’,’ or ’ ;’ before
  ’int’
  int __mingw_sleep( unsigned long, unsigned long ) ;
  ^
  In file included from c :\mingw\include\zconf.h:452:0,
  from c :\mingw\include\zlib.h:34,
  from c :/Work/FFMPEG_2.8.4/src/libavcodec/pngenc.c:35 :
  c :\mingw\include\unistd.h:105:1 : error : expected ’,’ or ’ ;’ before
  ’int’
  int nanosleep( const struct timespec *, struct timespec * ) ;
  ^
  c :\mingw\include\unistd.h:125:28 : error : expected ’,’ or ’ ;’
  before ’usleep’
  int _cdecl __MINGW_NOTHROW usleep( useconds_t
  )__MINGW_ATTRIB_DEPRECATED ;
  ^
  c :\mingw\include\unistd.h:138:10 : error : conflicting types for ’_cdecl’
  unsigned _cdecl
  __MINGW_NOTHROW sleep( unsigned ) ;
  ^
  c :\mingw\include\unistd.h:125:5 : note : previous declaration of ’_cdecl’ was here

  int _cdecl _MINGW_NOTHROW usleep( useconds_t
  )_MINGW_ATTRIB_DEPRECATED ;
  ^
  c :\mingw\include\unistd.h:138:33 : error : expected ’,’ or ’ ;’ before ’sleep’
  unsigned _cdecl _MINGW_NOTHROW sleep( unsigned ) ;
  ^
  c :\mingw\include\unistd.h:153:12 : error : expected ’=’, ’,’, ’ ;’, ’asm’ or ’_att
  ribute__’ before
  ’ftruncate’ int _cdecl ftruncate( int, off_t ) ;
  ^
  make : *** [libavcodec/pngenc.o] Error 1

  Similar issue was faced by someone and I provided a solution (workaround) in another forum

  Recently, I started FFMPEG compilation targeting to 64-bit. FFMPEG code (version 2.8.4) downloaded from the ffmpeg site compiled straight for 64-bit. I was expecting errors, but surprisingly I don’t see above errors. Then I thought FFMPEG could have fixed the issues, but it started showing up above errors again when I compiled it for 32-bit. Initially I thought it may be to do with my compilation environment, but similar issue was faced by some other people as well. So, I can confidently rule out the compilation environment factor.

  So the question here is, how come above error is specific to 32-bit. I couldn’t understand a bit, any idea about this behavior ??

• Rails ActionController::Live - Sends everything at once instead of async

  28 janvier 2016, par Michael B

  I have an issue with rails ActionController::Live

  In the end I want to show the progress of FFMPEG to the user, but for now I want to get this minimal example running :

  Rails media_controller.rb :

  class MediaController < ApplicationController
  
    include ActionController::Live
  
  
  
    def stream
  
      puts "stream function loaded"
  
  
  
        response.headers['Content-Type'] = 'text/event-stream'
  
        i = 0
  
        begin
  
          response.stream.write "data: 1\n\n"
  
          sleep 0.5
  
          i += 1
  
          puts "response... data: " + i.to_s
  
        end while i < 10
  
      response.stream.close
  
    end
  
  end

  Javascript :

  source = new EventSource("/test/0");
  
  source.addEventListener("message", function(response) {
  
    // Do something with response.data
  
    console.log('I have received a response from the server: ' + response);
  
  }, false);

  When I navigate to the site, there are no JavaScript Errors showing. As soon as I navigate to the site, the "stream"-Action of the MediaController gets successfully called. I can verify this, by looking at the Server-Console. It gives me the following output. After every response line, there is a 500ms delay, like expected :

  stream function loaded
  
  response... data: 1
  
  response... data: 2
  
  response... data: 3
  
  response... data: 4
  
  response... data: 5
  
  response... data: 6
  
  response... data: 7
  
  response... data: 8
  
  response... data: 9
  
  response... data: 10
  
  Completed 200 OK in 5005ms (ActiveRecord: 0.8ms)

  On the JavaScript Side, it gives me the following Output :

  (10x) I have received a response from the server: [object MessageEvent]

  But the problem is here, that it sends all these 10 Messages from the server after 5 seconds at the same time ! The expected behavior however is, that it should send me 1 message every 0.5 seconds !

  So what am I doing wrong here ? Where is the error ?

  

• What's the reason of failed to read from input stream while playing in ffmpeg

  5 février 2016, par Long Bai

  I’m using ffmpeg library in qt compiled with mingw.
  I’m going to read from rtmp stream, process video frame and write to another rtmp stream.
  I refered ffmpeg examples and developed it.
  It works well with local video stream.
  But on the internet stream, it is failed to read from input stream after a few seconds playing.
  What’s the reason of this problem ?
  Thanks for your answer.

  Here is my code.
  as you can see the following, on the line "ret=av_read_frame(m_pInContext,&inPacket)" return negative value.

  while (!m_bAborted)
  
  // read stream.
  int64_t tstart = av_gettime_relative() ;
  ret = av_read_frame(m_pInContext, &inPacket) ;
  if (ret < 0)
  SetError("Failed to read input stream.") ;
  break ;
  //continue ;
  

      if (inPacket.stream_index == m_nVideoStreamIdx)
  
      {
  
          do
  
          {
  
              // decode frame.
  
              int decodedLen = DecodePacket(m_pInFrame, &inPacket, &got_frame, 1);
  
              if (decodedLen < 0)
  
                  break;
  
  
  
              if (got_frame)
  
              {
  
                  // convert frame from yuv420 to rgb24.
  
                  if (sws_ctx1)
  
                  {
  
                      sws_scale(sws_ctx1, m_pInFrame->data, m_pInFrame->linesize, 0, m_nHeight, pRawData, arrRawDataLineSize);
  
                  }
  
  
  
                  // image processing to remove the code and ads on video.
  
                  if (m_pListener)
  
                      m_pListener->OnFrame(pRawData[0], m_nWidth, m_nHeight, arrRawDataLineSize[0], AV_PIX_FMT_RGB24, 24);
  
  
  
                  // convert from rgb24 to yuv420 to write to the output stream.
  
                  if (sws_ctx2)
  
                  {
  
                      sws_scale(sws_ctx2, pRawData, arrRawDataLineSize, 0, m_nHeight, m_dst_picture.data, m_dst_picture.linesize);
  
                  }
  
  
  
                  // increase frame number.
  
                  frameCount ++;
  
  
  
                  // write to the output stream.
  
                  ret = WriteVideoFrame(m_pOutContext, m_pOutVideoStream, &frameCount);
  
                  if (ret < 0) {
  
                      if (sws_ctx2)
  
                          sws_freeContext(sws_ctx2);
  
                      sws_ctx2 = NULL;
  
                      CloseOutputStream();
  
  
  
                      SetError("Failed to write video stream.");
  
                  }
  
  
  
                  // estimate frame time and sleep.
  
                  //clock_t tend = clock();
  
                  int64_t tend = av_gettime_relative();
  
                  frameDuration = tend-tstart;//(long)(1000 * (tend - tstart) / CLOCKS_PER_SEC);
  
                  if (1000*frameTime - frameDuration > 0)
  
                      av_usleep(1000*frameTime - frameDuration);
  
                      //QThread::msleep(frameTime - frameDuration);
  
                  tstart = tend;
  
              }
  
  
  
              // if there is another frame in the packet, then loop.
  
              inPacket.size -= decodedLen;
  
              inPacket.data += decodedLen;
  
          }while(inPacket.size > 0);
  
      }
  
  
  
      else if (m_pOutContext)
  
      {
  
  
  
      }
  
  
  
      av_packet_unref(&inPacket);
  
  }