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• Recording a webpage stream with multiple requests using PhantomJS & ffmpeg to /dev/stdout leads to ffmpeg error

  2 septembre 2016, par Allisson Ferreira

  First of all, sorry for my english.

  I’m in a quest for days. I’ve researched everywhere and I couldn’t find an answer to my problem.

  I’m using Nodejs, Phantomjs and ffmpeg in this scenary :

  • An user enters the site, login with facebook and he can ask for a video with his name and some random photos (gathered by /me/ & sent via JSON POST) ;
  • Node receive the user data, creates a child process (PhantomJS + ffmpeg) and awaits for a response to send the video URL to the user.

  When I run a single instance of this request, everything is working fine. BUT, when two or more users make the request, only one video is sent and the others process end up in a ffmpeg stream error.

  I think the reason is that all the ffmpeg processes are using the same place (/dev/stdout). Since one process is already using it, the others enters in a "can’t access" error. But it is a assumption, I don’t know how /dev/stdout really works.

  Here are my codes. (I have removed some lines and renamed some variables for better understanding, sorry for any mistake)

  index.js :

  var generateVideo = 'phantomjs phantom.js '+videoID+' '+userID+' | ffmpeg -vcodec png -f image2pipe -r 30 -i - -pix_fmt yuv420p public/videos/'+userID+'/'+videoID+'.mp4 -y';
  
  
  
  childProcess.exec(generateVideo, function(err, stdout, stderr) {
  
      var json    = {};
  
      json.video  = '/videos/'+userID+'/'+videoID+'.mp4';
  
      res.send(json);
  
  });

  phantom.js :

  var page            = require('webpage').create();
  
  page.viewportSize   = { width: 1366, height: 768 };
  
  page.settings.resourceTimeout = 10000;
  
  
  
  var args            = require('system').args;
  
  var videoID         = args[1];
  
  var userID          = args[2];
  
  
  
  page.open('http://localhost:3000/recordvideo/'+videoID, 'post', function(status){
  
      var frame       = 0;
  
      var target_fps  = 30;
  
      var maxframes   = page.evaluate(function () {
  
                          return getTotalDurationInSeconds();
  
                      }) * target_fps;
  
  
  
      setInterval(function(){
  
          page.render('/dev/stdout', { format: "png" });
  
          if( frame >= maxframes ){
  
              phantom.exit();
  
          }
  
          frame++;
  
      }, (1000 / target_fps));
  
  });

  And the error :

  [Error: Command failed: /bin/sh -c phantomjs phantom.js XXXXXXXX XXXXXXXX | ffmpeg -vcodec png -f image2pipe -r 30 -i - -pix_fmt yuv420p public/videos/XXXXXXXX/XXXXXXXX.mp4 -y
  
  www-0 ffmpeg version N-80901-gfebc862 Copyright (c) 2000-2016 the FFmpeg developers
  
  www-0   built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  
  www-0   configuration: --extra-libs=-ldl --prefix=/opt/ffmpeg --mandir=/usr/share/man --enable-avresample --disable-debug --enable-nonfree --enable-gpl --enable-version3 --enable-libopencore-amrnb --enable-libopencore-amrwb --disable-decoder=amrnb --disable-decoder=amrwb --enable-libpulse --enable-libfreetype --enable-gnutls --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-libvorbis --enable-libmp3lame --enable-libopus --enable-libvpx --enable-libspeex --enable-libass --enable-avisynth --enable-libsoxr --enable-libxvid --enable-libvidstab
  
  www-0   libavutil      55. 28.100 / 55. 28.100
  
  www-0   libavcodec     57. 48.101 / 57. 48.101
  
  www-0   libavformat    57. 41.100 / 57. 41.100
  
  www-0   libavdevice    57.  0.102 / 57.  0.102
  
  www-0   libavfilter     6. 47.100 /  6. 47.100
  
  www-0   libavresample   3.  0.  0 /  3.  0.  0
  
  www-0   libswscale      4.  1.100 /  4.  1.100
  
  www-0   libswresample   2.  1.100 /  2.  1.100
  
  www-0   libpostproc    54.  0.100 / 54.  0.100
  
  www-0 [png @ 0x3d7c4a0] Invalid PNG signature 0x46726F6D20506861.
  
  www-0 [image2pipe @ 0x3d72780] decoding for stream 0 failed
  
  www-0 [image2pipe @ 0x3d72780] Could not find codec parameters for stream 0 (Video: png, none(pc)): unspecified size
  
  www-0 Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  www-0 Input #0, image2pipe, from 'pipe:':
  
  www-0   Duration: N/A, bitrate: N/A
  
  www-0     Stream #0:0: Video: png, none(pc), 30 tbr, 30 tbn, 30 tbc
  
  www-0 [buffer @ 0x3d81540] Unable to parse option value "0x0" as image size
  
  www-0 [buffer @ 0x3d81540] Unable to parse option value "-1" as pixel format
  
  www-0 [buffer @ 0x3d81540] Unable to parse option value "0x0" as image size
  
  www-0 [buffer @ 0x3d81540] Error setting option video_size to value 0x0.
  
  www-0 [graph 0 input from stream 0:0 @ 0x3d72600] Error applying options to the filter.
  
  www-0 Error opening filters!
  
  www-0 ]

  I really hope that I can find an answer here !
  And sorry if there already is an answer for this. But I researched for days.

  Thank you in advance !

• Cannot use ffmpeg in qt on windows

  10 septembre 2016, par Johnnylin

  In my source file, I have the following include :

  #define __STDC_CONSTANT_MACROS
  
  
  
  extern "C" {
  
  #include "libavcodec/avcodec.h"
  
  #include "libavutil/imgutils.h"
  
  #include "libavutil/opt.h"
  
  #include "libswscale/swscale.h"
  
  }

  and in .pro file, I have :

  INCLUDEPATH += Z:\new_project\ffmpeg\include
  
  LIBS += -L"Z:/new_project/ffmpeg/lib" \
  
       -lavformat \
  
       -lavcodec \
  
       -lswscale \
  
       -lavutil

  In a function I call this :

      QImage YV12ToRGB24_FFmpeg(unsigned char* pYUV, int width, int height)
  
      {
  
          if (width < 1 || height < 1 || pYUV == NULL)
  
              return QImage();
  
  
  
          int length = height * width * 3;
  
          uchar* pRGB24 = new uchar[length];
  
  
  
          AVFrame pFrameYUV, pFrameRGB;
  
          av_image_fill_arrays(pFrameYUV.data, pFrameYUV.linesize, pYUV, AV_PIX_FMT_YUV420P, width, height, 1);
  
          //.......other operations.....//
  
     }

  when I run build in QtCreator, I got this error :

  undefined reference to 'av_image_fill_arrays'

  Can any one help ?

  BTW, I use ffmpeg-3.0-windows64-dev, and My qt use Qt5.7, QtCreator build use mingw32-make.

  EDIT :

  Compilation output :

  C:\Qt\Qt5.7.0\5.7\mingw53_32\bin\qmake.exe -spec win32-g++ -o Makefile ..\new_project.pro
  
  C:/Qt/Qt5.7.0/Tools/mingw530_32/bin/mingw32-make -f Makefile.Release
  
  mingw32-make[1]: Entering directory 'Z:/new_project/build'
  
  g++ -Wl,-s -Wl,-subsystem,windows -mthreads -o release\new_project.exe object_script.new_project.Release  -lmingw32 -LC:\Qt\Qt5.7.0\5.7\mingw53_32\lib C:\Qt\Qt5.7.0\5.7\mingw53_32\lib\libqtmain.a -LC:\utils\postgresql\pgsql\lib -LC:\utils\my_sql\my_sql\lib -lshell32 -LZ:\new_project\ffmpeg\lib -lavformat -lavcodec -lswscale -lavutil -LZ:\new_project\opencv_3.0\x86\mingw\bin -lopencv_core300 -lopencv_imgproc300 -lopencv_highgui300 -lopencv_imgcodecs300 C:\Qt\Qt5.7.0\5.7\mingw53_32\lib\libQt5Widgets.a C:\Qt\Qt5.7.0\5.7\mingw53_32\lib\libQt5Gui.a C:\Qt\Qt5.7.0\5.7\mingw53_32\lib\libQt5Core.a release\icon_res.o 
  
  
  
  
  
  ./release\camera_node.o:camera_node.cpp:(.text+0x464): undefined reference to `av_image_fill_arrays'
  
  collect2.exe: error: ld returned 1 exit status

• libavformat/mov : Accept known codepoints in ’colr’

  17 août 2016, par Steven Robertson

  libavformat/mov : Accept known codepoints in ’colr’
  This change relaxes the whitelist on reading color metadata in MOV/BMFF
  
  containers. The whitelist on writing values is still in place.
  As a consequence it also fixes an apparent bug in reading ’nclc’ values.
  
  The ’nclc’ spec [1] is in harmony with ISO 23001-8 for the values it
  
  lists, but the code getting removed was remapping 5->6 and 6->7 for
  
  primaries, which is incorrect, and was remapping 6->5 for color matrix
  
  ("colorspace" in the code), which is equivalent but an unnecessary
  
  inconsistency. This logic error doesn’t appear in movenc.
  Removing the whitelist allows proper conversion when the source codec
  
  relies on the container for proper signaling of newer codepoints, such
  
  as DNxHR and VP9. If converting to a codec or container that has updated
  
  its spec to include the new codepoints, the metadata will be preserved.
  
  If going back to MOV/BMFF, the output whitelist will still kick in, so
  
  this won’t result in out-of-spec files being created.
  [1] https://developer.apple.com/library/mac/technotes/tn2162/_index.html
  Signed-off-by : Steven Robertson <steven@strobe.cc>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/mov.c