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• How do I properly enable ffmpeg for matplotlib.animation ?

  9 novembre 2018, par spanishgum

  I have covered a lot of ground on stack so far trying to get ffmpeg going so I can make a timelapse video.

  I am on a CentOS 7 machine, running python3.7.0a0.

  python3
  
  >>> import numpy as np
  
  >>> np.__version__
  
  '1.12.0'
  
  >>> import matplotlib as mpl
  
  >>> mpl.__version__
  
  '2.0.0'
  
  >>> import mpl_toolkits.basemap as base
  
  >>> base.__version__
  
  '1.0.7'

  I found this github gist on installing ffmpeg. I used the chromium source, and installed without a prefix option (using the default).

  I have confirmed that ffmpeg is installed, although I don’t know anything about testing whether it works.

  which ffmpeg
  
  /usr/local/bin/ffmpeg
  
  
  
  ffmpeg -version
  
  ffmpeg version N-83533-gada281d Copyright (c) 2000-2017 the FFmpeg dev elopers
  
  built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-11
  
  configuration:
  
  libavutil      55. 47.100 / 55. 47.100
  
  libavcodec     57. 80.100 / 57. 80.100
  
  libavformat    57. 66.102 / 57. 66.102
  
  libavdevice    57.  2.100 / 57.  2.100
  
  libavfilter     6. 73.100 /  6. 73.100
  
  libswscale      4.  3.101 /  4.  3.101
  
  libswresample   2.  4.100 /  2.  4.100

  I tried to run a few sample examples I found online :

  [1] http://matplotlib.org/examples/animation/basic_example_writer.html

  [2] https://stackoverflow.com/a/23098090/3454650

  Everything works fine up until I try to save the animation file.

  [1]

   anim.save('basic_animation.mp4', writer = FFwriter, fps=30, extra_args=['-vcodec', 'libx264'])

  [2]

  im_ani.save('im.mp4', writer=writer)

  I found here that explictly setting the path to ffmpeg might be necessary so I added this to the top of the test scripts :

  plt.rcParams['animation.ffmpeg_path'] = '/usr/local/bin/ffmpeg'

  I tried a few more tweaks in the code but always get the same response, which I do not know how to begin deciphering :

  Traceback (most recent call last):
  
    File "testanim.py", line 27, in <module>
  
      writer.grab_frame()
  
    File "/usr/local/lib/python3.7/contextlib.py", line 100, in __exit__
  
      self.gen.throw(type, value, traceback)
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 256, in saving
  
      self.finish()
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 276, in finish
  
      self.cleanup()
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 311, in cleanup
  
      out, err = self._proc.communicate()
  
    File "/usr/local/lib/python3.7/subprocess.py", line 836, in communicate
  
      stdout, stderr = self._communicate(input, endtime, timeout)
  
    File "/usr/local/lib/python3.7/subprocess.py", line 1474, in _communicate
  
      selector.register(self.stdout, selectors.EVENT_READ)
  
    File "/usr/local/lib/python3.7/selectors.py", line 351, in register
  
      key = super().register(fileobj, events, data)
  
    File "/usr/local/lib/python3.7/selectors.py", line 237, in register
  
      key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data)
  
    File "/usr/local/lib/python3.7/selectors.py", line 224, in _fileobj_lookup
  
      return _fileobj_to_fd(fileobj)
  
    File "/usr/local/lib/python3.7/selectors.py", line 39, in _fileobj_to_fd
  
      "{!r}".format(fileobj)) from None
  
  ValueError: Invalid file object: &lt;_io.BufferedReader name=6>
  
  </module>

  Is there something with my configuration that is malformed ? I searched google for this error for some time but never found anything relevant to animations / ffmpeg. Any help would be greatly appreciated.

  ---

  UPDATE :

  @LordNeckBeard pointed me here : https://trac.ffmpeg.org/wiki/CompilationGuide/Centos

  I ran into problems with installing the x264 encoding dependency. Some files in libavcodec/*.c (in the make output) were reporting undefined references to several functions. After a wild goose chase found this : https://mailman.videolan.org/pipermail/x264-devel/2015-February/010971.html

  To fix the x264 installation, I simply added some configure flags :

  ./configure --enable-static --enable-shared --extra-ldflags="-lswresample -llzma"

  ---

  UPDATE :

  So everything installed fine after fixing the libx264 problems. I went ahead and copied the ffmpeg binary from the ffmpeg_build folder into /usr/local/bin/ffmpeg.

  After running the script I was getting problems where ffmpeg could not find the libx264 shared object. I think I will have to recompile everything using different prefixes. My intuition tells me there are old files laying around after I have messed with everything, using some configuration that is broken.

  So I decided maybe I should just try to use NUX : http://linoxide.com/linux-how-to/install-ffmpeg-centos-7/
  I installed ffmpeg using the new rpm, but to no avail. I still was not able to run ffmpeg because of a missing shared object.

  Finally, instead of usiong files copied into my /usr/local/bin folder, I ran ffmpeg directly from the build bin directory. Turns out that this does work properly !

  So in essence, if I want to install ffmpeg system wide, I need to manually compile from sources again but using a nonlocal prefix.

• (ffmpeg.autogen)How can i Play RTSP Stream Audio With Video

  1er octobre 2018, par newbie

  I am making rtsp stream player to use opencv..

  The example Project is wonderful.

  But that is with not Sound

  I Added thid Code and I think I found Audio Stream Number, but I don’t know next step

      private readonly AVCodecContext* _aCodecContext;
  
      private readonly AVFormatContext* _aFormatContext;
  
      private readonly int _a_streamIndex;
  
  
  
      public VideoStreamDecoder(string url)
  
      {
  
          _vFormatContext = ffmpeg.avformat_alloc_context();
  
  
  
          var pFormatContext = _vFormatContext;
  
          ffmpeg.avformat_open_input(&pFormatContext, url, null, null).ThrowExceptionIfError();
  
  
  
          ffmpeg.avformat_find_stream_info(_vFormatContext, null).ThrowExceptionIfError();
  
  
  
          // find the first video stream
  
          AVStream* vStream = null;
  
          for (var i = 0; i < _vFormatContext->nb_streams; i++)
  
              if (_vFormatContext->streams[i]->codec->codec_type == AVMediaType.AVMEDIA_TYPE_VIDEO)
  
              {
  
                  vStream = _vFormatContext->streams[i];
  
                  break;
  
              }
  
  
  
          // find Audio stream
  
          AVStream* aStream = null;
  
          for (var i = 0; i < _vFormatContext->nb_streams; i++)
  
              if (_vFormatContext->streams[i]->codec->codec_type == AVMediaType.AVMEDIA_TYPE_AUDIO)
  
              {
  
                  aStream = _vFormatContext->streams[i];
  
                  break;
  
              }
  
  
  
          if (vStream == null) throw new InvalidOperationException("Could not found video stream.");
  
  
  
          _v_streamIndex = vStream->index;
  
          _vCodecContext = vStream->codec;
  
  
  
          _a_streamIndex = aStream->index;
  
          _aCodecContext = aStream->codec;
  
  
  
          var vcodecId = _vCodecContext->codec_id;
  
          var vCodec = ffmpeg.avcodec_find_decoder(vcodecId);
  
  
  
          var acodecId = _aCodecContext->codec_id;
  
          var aCodec = ffmpeg.avcodec_find_decoder(acodecId);
  
  
  
          if (vCodec == null) throw new InvalidOperationException("Unsupported codec.");
  
  
  
          ffmpeg.avcodec_open2(_vCodecContext, vCodec, null).ThrowExceptionIfError();
  
          ffmpeg.avcodec_open2(_aCodecContext, aCodec, null).ThrowExceptionIfError();
  
  
  
          vCodecName = ffmpeg.avcodec_get_name(vcodecId);
  
          aCodecName = ffmpeg.avcodec_get_name(acodecId);
  
          FrameSize = new Size(_vCodecContext->width, _vCodecContext->height);
  
          PixelFormat = _vCodecContext->pix_fmt;
  
  
  
          _pPacket = ffmpeg.av_packet_alloc();
  
          _pFrame = ffmpeg.av_frame_alloc();
  
      } 

• on('progress') not working - node.js ytdl-core fluent-ffmpeg

  9 juillet 2018, par TheBandolero

  So i’m playing with this libraries ytdl-core and fluent-ffmpeg, and basically i got to this function by modifying some examples to fit what i wanted.

  everything works fine except for the second on('progress', progress => ....) call. The first one works as expected, but the second one looks like it isn’t even reached, since Console.log() inside the second on('progress'....) isn’t logging anything at all.

  Also console doesn’t show any errors throughout the whole function, and the outcome is the expected without any problem, except for the second on('progress') issue.

  I can’t figure out what the problem is, so I hope somebody with more experience can point the problem out to me, since it’s getting quite frustrating now...

  function descargarVideoHD(link) {
  
          ytdl.getInfo(link, (err, info) => {
  
              if (err) throw err;
  
  
  
              $('li:contains(' + link + ') .progress').css("visibility", "visible");
  
  
  
              var longitudEnTiempo = parseInt(info.length_seconds);
  
              let id = ytdl.getURLVideoID(link);
  
              var titulo = limpiarTituloDelVideo(info.title);
  
  
  
              let stream = ytdl(id, {
  
                  quality: 'highestaudio',
  
                  //filter: 'audioonly',
  
              });
  
  
  
              //var audioOutput = path.resolve(__dirname, 'audio_' + titulo + '.mp4');
  
              var mainOutput = path.resolve(__dirname, titulo + '.mp4');
  
              var renameFileName = titulo + '.mp4';
  
  
  
              var audioOutput = path.resolve(__dirname, titulo + '.mp3');
  
  
  
              ffmpeg(stream)
  
                  //.audioBitrate(128)
  
                  .audioBitrate(256)
  
                  .save(`${__dirname}/${titulo}.mp3`)
  
                  .on('progress', (p) => {
  
                      //readline.cursorTo(process.stdout, 0);
  
                      //process.stdout.write(`${p.targetSize}kb downloaded`);
  
                      var hmsA = p.timemark;
  
                      var aA = hmsA.split(':');
  
                      var secondsA = parseInt((+aA[0]) * 60 * 60 + (+aA[1]) * 60 + (+aA[2]));
  
                      var porcentageA = (((secondsA / longitudEnTiempo) * 100) / 2).toFixed(2);
  
                      $('li:contains(' + link + ') .progress .determinate').css("width", porcentageA + "%");
  
                      //console.log(titulo + ' procesado al ' + porcentage + '%');
  
                  })
  
                  .on('end', () => {
  
                      ffmpeg()
  
                          .input(ytdl(link, {
  
                              filter: format => {
  
                                  return format.container === 'mp4' && !format.audioEncoding;
  
                              }
  
                          }))
  
                          .videoCodec('copy')
  
                          .input(audioOutput)
  
                          .audioCodec('copy')
  
                          .save(mainOutput)
  
                          .on('error', console.error)
  
                          .on('progress', progress => {
  
                              console.log('Dentro de OnProgress...');
  
                              var hms = progress.timemark;
  
                              console.log('Timemark: ' + hms);
  
                              var a = hms.split(':');
  
                              var seconds = parseInt((+a[0]) * 60 * 60 + (+a[1]) * 60 + (+a[2]));
  
                              console.log('Segundos: ' + seconds);
  
                              var porcentage = ((((seconds / longitudEnTiempo) * 100) / 2) + 50).toFixed(2);
  
                              console.log('Procesado al ' + porcentage + '%');
  
                              $('li:contains(' + link + ') .progress .determinate').css("width", porcentage + "%");
  
                          }).on('end', () => {
  
                              fs.unlink(audioOutput, err => {
  
                                  if (err) {
  
                                      console.error(err);
  
                                  }
  
                                  else {
  
                                      $('li:contains(' + link + ') .progress .determinate').css("width", "100%");
  
                                      $('li:contains(' + link + ') .secondary-content.material-icons').text('done');
  
                                      $('li:contains(' + link + ') .secondary-content.material-icons').addClass('text-green');
  
                                      /* $('li:contains(' + link + ')').remove();
  
                                      var indexItem = listaEnlacesYoutube.indexOf(link);
  
                                      listaEnlacesYoutube.splice(indexItem, 1); */
  
                                  }
  
                              });
  
                          });
  
                  });
  
          });
  
      }