Sur d’autres sites (6966)

• Does ffmpeg version 0.5 configured on linux support encoding using Theora codec ?

  2 août 2012, par goldenmean

  I have configured, compiled a FFmpeg source code version 0.5 with versions as below :

  FFmpeg version 0.5, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  
    configuration: --enable-memalign-hack
  
    libavutil     49.15. 0 / 49.15. 0
  
    libavcodec    52.20. 0 / 52.20. 0
  
    libavformat   52.31. 0 / 52.31. 0
  
    libavdevice   52. 1. 0 / 52. 1. 0

  on a linux host.

  When I try to encode a raw yuv video using this version using theora codec by giving options as :

  ffmpeg -f rawvideo -pix_fmt yuv420p -s 352x288 -r 30 -i foreman_352_x280_420.yuv -an -vcodec libtheora theora1.ogg

  It gives an error : Unknown encoder 'libtheora'

  But when i use the same command in a FFmpeg windows executable ( whose version is FFmpeg version SVN-r12665) it encoded to a theora video properly.

  1. Doesnt ffmpeg version 0.5 on linux support theora encoder ?
  2. Which version for linux setup,would support theora encoding ?

• Anomalie #3014 : Chaines de langue de "Forums" utilisées dans la "dist"

  24 décembre 2017, par b b

  Pour info, voici les occurrences de chaînes de langue de forum dans la dist à ce jour :

  grep -nHIirF —exclude=*.svn-base — :forum : .
  ./404.html:36 :            [(#ENVfond_erreur|==forum|oui)
  
  <:forum:aucun_message_forum :>
  
  ]
  
  ./article.html:56 :            [
  <:forum:form_pet_message_commentaire :>
  ./inclure/forum.html:17 :                [(#CONFIGforums_titre| !=non|oui)#COMPTEUR_BOUCLE.
  
  ./inclure/forum.html:42 :                        [(#CONFIGforums_titre| !=non|oui)#COMPTEUR_BOUCLE.
  
  ./forum.html:11 :    
  
  ./forum.html:25 :
  
  <:accueil_site :> &gt ; ... &gt ; <:forum:forum :> #ID_FORUM
  
  ./forum.html:28 :                [
  (#TITRE|sinon<:forum:forum :> #ID_FORUM)
  ]
  
  ./forum.html:38 :
  <:forum:forum_avez_selectionne :> #TITRE
  
  ./forum.html:41 :            [
  <:forum:form_pet_message_commentaire :>
  ./breve.html:43 :            [
  <:forum:form_pet_message_commentaire :>
  
  

• How would I assign multiple MMAP's from single file descriptor ?

  9 juin 2011, par Alex Stevens

  So, for my final year project, I'm using Video4Linux2 to pull YUV420 images from a camera, parse them through to x264 (which uses these images natively), and then send the encoded stream via Live555 to an RTP/RTCP compliant video player on a client over a wireless network. All of this I'm trying to do in real-time, so there'll be a control algorithm, but that's not the scope of this question. All of this - except Live555 - is being written in C. Currently, I'm near the end of encoding the video, but want to improve performance.

  To say the least, I've hit a snag... I'm trying to avoid User Space Pointers for V4L2 and use mmap(). I'm encoding video, but since it's YUV420, I've been malloc'ing new memory to hold the Y', U and V planes in three different variables for x264 to read upon. I would like to keep these variables as pointers to an mmap'ed piece of memory.

  However, the V4L2 device has one single file descriptor for the buffered stream, and I need to split the stream into three mmap'ed variables adhering to the YUV420 standard, like so...

  buffers[n_buffers].y_plane = mmap(NULL, (2 * width * height) / 3,
  
                                      PROT_READ | PROT_WRITE, MAP_SHARED,
  
                                      fd, buf.m.offset);
  
  buffers[n_buffers].u_plane = mmap(NULL, width * height / 6,
  
                                      PROT_READ | PROT_WRITE, MAP_SHARED,
  
                                      fd, buf.m.offset +
  
                                      ((2 * width * height) / 3 + 1) /
  
                                      sysconf(_SC_PAGE_SIZE));
  
  buffers[n_buffers].v_plane = mmap(NULL, width * height / 6,
  
                                      PROT_READ | PROT_WRITE, MAP_SHARED,
  
                                      fd, buf.m.offset +
  
                                      ((2 * width * height) / 3 + 
  
                                      width * height / 6 + 1) / 
  
                                      sysconf(_SC_PAGE_SIZE));

  Where "width" and "height" is the resolution of the video (eg. 640x480).

  From what I understand... MMAP seeks through a file, kind of like this (pseudoish-code) :

  fd = v4l2_open(...);
  
  lseek(fd, buf.m.offset + (2 * width * height) / 3);
  
  read(fd, buffers[n_buffers].u_plane, width * height / 6);

  My code is located in a Launchpad Repo here (for more background) :
  http://bazaar.launchpad.net/ alex-stevens/+junk/spyPanda/files (Revision 11)

  And the YUV420 format can be seen clearly from this Wiki illustration : http://en.wikipedia.org/wiki/File:Yuv420.svg (I essentially want to split up the Y, U, and V bytes into each mmap'ed memory)

  Anyone care to explain a way to mmap three variables to memory from the one file descriptor, or why I went wrong ? Or even hint at a better idea to parse the YUV420 buffer to x264 ? :P

  Cheers ! ^^