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• lavu/opt : fix range check logic in set_format()

  16 décembre 2013, par Stefano Sabatini

  lavu/opt : fix range check logic in set_format()
  In particular, allow to reject undefined values. Previously the code
  
  was only accepting values in the range -1 .. NB_FORMATS-1.
  

  • [DH] libavutil/opt.c

• avformat/matroskadec : Improve invalid length error handling

  17 mai 2019, par Andreas Rheinhardt

  avformat/matroskadec : Improve invalid length error handling
  1. Up until now, the error message for EBML numbers whose length exceeds
  
  the limits imposed upon them because of the element's type did not
  
  distinguish between known-length and unknown-length elements. As a
  
  consequence, the numerical value of the define constant
  
  EBML_UNKNOWN_LENGTH was emitted as part of the error message which is
  
  of course not appropriate. This commit changes this by adding error
  
  messages designed for unknown-length elements.
  2. We impose some (arbitrary) sanity checks on the lengths of certain
  
  element types ; these checks were conducted before the checks depending
  
  on whether the element exceeds its containing master element. Now the
  
  order has been reversed, because a failure at the (formerly) latter
  
  check implies that the file is truly erroneous and not only fails our
  
  arbitrary length limit. Moreover, this increases the informativeness of
  
  the error messages.
  3. Furthermore, the error message in general has been changed by replacing
  
  the type of the element (something internal to this demuxer and
  
  therefore suitable as debug output at best, not as an error message
  
  intended for ordinary users) with the element ID. The element's position
  
  has been added, too.
  4. Finally, the length limit for EBML_NONE elements has been changed so
  
  that all unknown-length elements of EBML_NONE-type trigger an error.
  
  This is done because unknown-length elements can't be skipped and need
  
  to be parsed, but there is no syntax to parse available for EBML_NONE
  
  elements. This is done in preparation for a further patch which allows
  
  more unknown-length elements than just clusters and segments.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskadec.c

• Real time stereo video stream. How to start

  29 juin 2015, par victor jung

  Here is my problem :

  I have at one side two webcams plugged in a linux computer, and on the other side, an android smartphone. My goal is to program a real time stream of the 2 webcams, and display that stream on the smartphone (to be used in a google cardboard mask). I read quite a lot on the subject, and I found several way to achieve this.

  First there is ffmpeg, which could encode and stream.

  But I need to modify the pictures at some point, to re-size them / or to ad some kind of distortion. So I thought it would be great if I can get the 2 images, with openCv maybe, playwith them, build a new one, and stream them, but how could ffmpeg deal with the newly created image ?

  The other option would be to get the 2 pics and play with them with openCv too, but then, hardcode a stream over, UDP in RTP style, but wouldnt be hard to display the stream nicely on the phone ?, and how to cut the image to fit in small packets ?

  Thanks for your help, I am still digging in the subject, so if you have any other way to do it I am taking !

  ps : My introducing Hello, won’t stay at the beginning of my message...
  Have a nice day every body.
  d-4 before frieday.