Recherche avancée

Sur d’autres sites (8110)

• avcodec/jpeglsenc : Only use one line at a time as spare buffer

  3 septembre 2020, par Andreas Rheinhardt

  avcodec/jpeglsenc : Only use one line at a time as spare buffer
  ls_encode_line() encodes one line of input from left to right and
  
  to do so it uses the values of the left, upper left, upper and upper
  
  right pixels for prediction (i.e. the values that a decoder gets when it
  
  decodes the already encoded part of the picture). So a simple algorithm
  
  would use a buffer that can hold two lines, namely the current line as
  
  well as the last line and swap the pointers to the two lines after
  
  decoding each line. Yet if one is currently encoding the pixel with
  
  index k of a line, one doesn't need any pixel with index < k - 1 of the
  
  last line at all and similarly, no pixels with index >= k have been
  
  written yet. So the overlap in the effective lifetime is pretty limited
  
  and since the last patch (which stopped reading the upper left pixel and
  
  instead reused the value of the upper pixel from the last iteration of
  
  the loop) it is inexistent. Ergo one only needs one line and doesn't
  
  need to swap the lines out.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/jpeglsenc.c

• Visual Studio & ffmpeg : Building FFmpeg in visual studio - 'ffmpeg.obj'

  11 mai 2021, par Simba_cl25

  I am new here and I am trying to link ffmpeg with visual studio following some guides like :

  


  

  • http://ffmpeg.org/platform.html#Linking-to-FFmpeg-with-Microsoft-Visual-C_002b_002b

  


  


  I added librairies in the project propreties :

  


  

  • In C/C++ —> General —> Additional Include Directories

  


  • In Linker —> General —> Additional Library Directories

  


  • In Linker —> Input —> Additional Dependencies

  


  


  But I have encountered the following problem :

  


  


  Error LNK1104 cannot open file 'ffmpeg.obj'

  


  


  I tried to add double quotes around path of the libraries but it hasn't changed the outcome.

  


  Nevertheless, I can't find anything about 'ffmpeg.obj'
What is this file ? What could I change to avoid this error ?

  


• Using Windows named pipes with ffmpeg pipes (Doesnt work)

  25 octobre 2019, par Estr

  I’m trying to send audio and video RAW through c# pipes to FFMPEG, I’ve been reading and trying to follow what’s shown here : https://docs.microsoft.com/en-us/dotnet/api/system.io.pipes.namedpipeserverstream?view=netframework-4.8

  This a fragment of the code...

          NamedPipeServerStream p_1;
  
          NamedPipeServerStream p_2;
  
          p_1 = new NamedPipeServerStream("p_1", PipeDirection.Out, 1, PipeTransmissionMode.Byte);
  
          p_2 = new NamedPipeServerStream("p_2", PipeDirection.Out, 1, PipeTransmissionMode.Byte);
  
  
  
          p_1.WaitForConnection();
  
  
  
          p_2.WaitForConnection();

  .......

  I run this command in FFMPEG : ffmpeg.exe -i \.\pipe\p_1 -vcodec hevc -r 8 -f alaw -ar:a 16000 -ac:a 1 -i \.\pipe\p_2 o.mp4

  But the program stays on the line : p_2.WaitForConnection() ;

  How can I solve it ?