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• FFmpeg resize without upscaling

  9 November 2016, by Alan

  I am working on a script that searches for all media files in the current directory and subdirectories and then batch encodes them to H.265. I was hoping to put in some max frame sizes to make things that are 1080p to be 720p. That is the straightforward part but I have some that are 480p and I don’t want those to end up as 720p. How can I modify my ffmpeg filters to take that into account?

  The command:

  ffmpeg -i input -c:v hevc_nvenc -preset medium -crf 28 -c:a copy output.mp4

• Read from UDP Multicast RTSP Video Stream

  24 April 2012, by hatboyzero

  I am currently developing an application that needs to decode a UDP multicast RTSP stream. At the moment, I can view the RTP stream using ffplay via

  ffplay -rtsp_transport udp_multicast rtsp://streamURLGoesHere

  However, I am trying to use FFMPEG to open the UDP stream via (error checking and cleanup code removed for the sake of brevity).

  AVFormatContext* ctxt = NULL;
  
  av_open_input_file(
  
      &ctxt,
  
      urlString,
  
      NULL,
  
      0,
  
      NULL
  
  );
  
  
  
  av_find_stream_info(ctxt);
  
  
  
  AVCodecContext* codecCtxt;
  
  
  
  int videoStreamIdx = -1;
  
  for (int i = 0; i < ctxt->nb_streams; i++)
  
  {
  
      if (ctxt->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
  
      {
  
          videoStreamIdx = i;
  
          break;
  
      }
  
  }
  
  
  
  AVCodecContext* codecCtxt = ctxt->streams[videoStreamIdx]->codec;
  
  AVCodec* codec = avcodec_fine_decoder(codecCtxt->codec_id);
  
  avcodec_open(codecCtxt, codec);
  
  
  
  AVPacket packet;
  
  while(av_read_frame(ctxt, &packet) >= 0)
  
  {
  
      if (packet.stream_index == videoStreamIdx)
  
      {
  
          /// Decoding performed here
  
          ...
  
      }
  
  }
  
  
  
  ...

  This approach works fine with file inputs that consist of a raw encoded video stream, but for UDP multicast RTSP streams, it fails any error checking performed on av_open_input_file(). Please advise...

• Anomalie #3633 (Nouveau): probleme appel de la mediabox

  2 January 2016, by tofulm -

  Bonjour,
  dans un squelette toto.html, j’ai un inclure en ajax avec un squelette qui comporte plusieurs liens de la forme
  

  &lt;script&gt;<br />
  
  jQuery(document).ready(function(){<br />
  
       jQuery(&quot;a.appel_mediabox&quot;).mediabox();<br />
  
  ...<br />
  
  &lt;/script&gt;
  
  

  au chargement de la page, j’ai les mediabox qui se lancent "vides" au lieu d’attendre le click sur le lien.

  le problème vient de :
  http://zone.spip.org/trac/spip-zone/browser/_core_/plugins/mediabox/javascript/spip.mediabox.js#L89

  Ce test n’était pas présent en spip 3.0 et le même code fonctionnait.

  Si je supprime ce test et le remplace par :
  

  return this.colorbox($.extend(cbox_options,options));
  

  tout est ok

  Merci