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• log : Print a full backtrace along with error messages under Valgrind

  20 avril 2015, par Vittorio Giovara

  log : Print a full backtrace along with error messages under Valgrind
  Useful to understand where and in what execution state a certain message
  
  is generated. It is enabled only when optimizations are disabled, since
  
  function names are not printed otherwise.
  Signed-off-by : Vittorio Giovara <vittorio.giovara@gmail.com>
  

  • [DH] configure
  • [DH] libavutil/log.c
  • [DH] libavutil/version.h

• Streaming Web cam real-time buffer [Toshiba Webcam] [video input] too full or near too full

  21 avril 2015, par esprittn

  I am trying to stream my webcam with audio from microphone of laptop(OS : windows 7 ) to nginx server (Compiled with rtmp module in CentOS 6.6 final) in same local network.
  From my laptop, I execute this command in CMD :

  ffmpeg -f dshow -i video="Toshiba Webcam" -f dshow -i audio="Microphone (Périphérique High D" -vf scale=1280:720 -vcodec libx264 -r 60.97 -acodec libvo_aacenc -ac 2 -ar 44100 -ab 128 -pix_fmt yuv420p -tune zerolatency -preset ultrafast -f flv "rtmp://172.16.40.162/dash/test"

  But I got this message :
  

  And I had about retard delay of 23 second when I open http://localhost:8080 ( I made the indx.html file of nginx with JWPlayer)

  So my questions are :

  How can I improve the ffmpeg cmd to avoid the errors of buffer too full ?

  How eliminate or reduce the latency ?

  Thanks for your help.

• FFMPEG AVCodec : How can I create a FULL copy of a decoder ?

  21 avril 2015, par damicolo

  I’m writing a video decoder (using FFMPEG/AVCodec) for a custom implementation of an mpeg4 video stream. The peculiarity of this video stream is that it could split into many "son" streams creating many P frames based on the same parent. The video stream I’m trying to decode is actually a sort of "video tree". Something like this :

  I <--P <--P <---------------------P <-------------- P <------------ P
  
             \ <--P <--P <--P        \ <--P <--P       \ <--P <--P 

  I’ve already wrote a basic decoder which works fine when I decide to follow one path, the problem is when I try to follow more than one path in the video tree. At this point I need to "fork" my decoder to follow two different video streams. the split could occur not only after a key frame, but even after a P frame, so I need to duplicate the AVCodecContext (I use avcodec_copy_context) but it seems to create new decoder from a clean status.. it seems to ignore the previous video status, so the decoded P frames are "applied" to an empty video frame.
  Probably copying the context using avcodec_copy_context is not enough... Any suggestion ? How can I duplicate the context and the complete status of the decoder ?
  Or, is there any other way to decode my stream using references ?
  Thanks !