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  • Des sites réalisés avec MediaSPIP

    2 mai 2011, par

    Cette page présente quelques-uns des sites fonctionnant sous MediaSPIP.
    Vous pouvez bien entendu ajouter le votre grâce au formulaire en bas de page.

  • Les autorisations surchargées par les plugins

    27 avril 2010, par

    Mediaspip core
    autoriser_auteur_modifier() afin que les visiteurs soient capables de modifier leurs informations sur la page d’auteurs

  • Possibilité de déploiement en ferme

    12 avril 2011, par

    MediaSPIP peut être installé comme une ferme, avec un seul "noyau" hébergé sur un serveur dédié et utilisé par une multitude de sites différents.
    Cela permet, par exemple : de pouvoir partager les frais de mise en œuvre entre plusieurs projets / individus ; de pouvoir déployer rapidement une multitude de sites uniques ; d’éviter d’avoir à mettre l’ensemble des créations dans un fourre-tout numérique comme c’est le cas pour les grandes plate-formes tout public disséminées sur le (...)

Sur d’autres sites (8494)

  • ffmpeg determine correct codec to use

    6 janvier 2015, par nha

    I am trying to use .y4m files that I feed into Chrome for playing.
    This is the only format that I can use.

    I have a set of .y4m files that are working for my use case, taken from here.
    For example let’s say that I use the file mobile_qcif_7.5fps.y4m.

    I also have a .mp4 file (specifically the sample small.mp4 file from techslides ). I know how to convert small.mp4 to small.y4m with the following command :

    ffmpeg -y -i small.mp4 small.y4m

    I would like the resulting file to be accepted by Chrome, just like the other file.
    What options should I use (and how to find them) ?

    Additional information

    ffprobe gives :

    $ ffprobe small.y4m 
    
avprobe version 0.8.13-6:0.8.13-0ubuntu0.13.10.1, Copyright (c) 2007-2014 the Libav developers
    
  built on Jul 15 2014 13:48:35 with gcc 4.8.1
    
[yuv4mpegpipe @ 0x23160c0] Estimating duration from bitrate, this may be inaccurate
    
Input #0, yuv4mpegpipe, from 'small.y4m':
    
  Duration: N/A, bitrate: N/A
    
    Stream #0.0: Video: rawvideo, yuv420p, 560x320, 30 fps, 30 tbr, 30 tbn, 30 tbc
    

    

    
$ ffprobe mobile_qcif_7.5fps.y4m
    
avprobe version 0.8.13-6:0.8.13-0ubuntu0.13.10.1, Copyright (c) 2007-2014 the Libav developers
    
  built on Jul 15 2014 13:48:35 with gcc 4.8.1
    
[yuv4mpegpipe @ 0x1e080c0] max_analyze_duration reached
    
[yuv4mpegpipe @ 0x1e080c0] Estimating duration from bitrate, this may be inaccurate
    
Input #0, yuv4mpegpipe, from 'mobile_qcif_7.5fps.y4m':
    
  Duration: N/A, bitrate: N/A
    
    Stream #0.0: Video: rawvideo, yuv420p, 176x144, PAR 128:117 DAR 1408:1053, 7.50 fps, 7.50 tbr, 7.50 tbn, 7.50 tbc

    OS : I am using ffmpeg in Ubuntu 13.10 from the default repository : I ran sudo apt-get install ffmpeg libavcodec-extra-53

    Complete console output

    $ ffmpeg -y -i small.mp4 small.y4m
    
ffmpeg version 0.8.13-6:0.8.13-0ubuntu0.13.10.1, Copyright (c) 2000-2014 the Libav developers
    
  built on Jul 15 2014 13:48:35 with gcc 4.8.1
    
*** THIS PROGRAM IS DEPRECATED ***
    
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
    
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'small.mp4':
    
  Metadata:
    
    major_brand     : mp42
    
    minor_version   : 0
    
    compatible_brands: mp42isomavc1
    
    creation_time   : 2010-03-20 21:29:11
    
    encoder         : HandBrake 0.9.4 2009112300
    
  Duration: 00:00:05.56, start: 0.000000, bitrate: 551 kb/s
    
    Stream #0.0(und): Video: h264 (Constrained Baseline), yuv420p, 560x320, 465 kb/s, 30 fps, 30 tbr, 90k tbn, 60 tbc
    
    Metadata:
    
      creation_time   : 2010-03-20 21:29:11
    
    Stream #0.1(eng): Audio: aac, 48000 Hz, mono, s16, 83 kb/s
    
    Metadata:
    
      creation_time   : 2010-03-20 21:29:11
    
[buffer @ 0x7274e0] w:560 h:320 pixfmt:yuv420p
    
Output #0, yuv4mpegpipe, to 'small.y4m':
    
  Metadata:
    
    major_brand     : mp42
    
    minor_version   : 0
    
    compatible_brands: mp42isomavc1
    
    creation_time   : 2010-03-20 21:29:11
    
    encoder         : Lavf53.21.1
    
    Stream #0.0(und): Video: rawvideo, yuv420p, 560x320, q=2-31, 200 kb/s, 90k tbn, 30 tbc
    
    Metadata:
    
      creation_time   : 2010-03-20 21:29:11
    
Stream mapping:
    
  Stream #0.0 -> #0.0
    
Press ctrl-c to stop encoding
    
frame=  166 fps=  0 q=0.0 Lsize=   43576kB time=5.53 bitrate=64513.5kbits/s    
    
video:0kB audio:0kB global headers:0kB muxing overhead inf%

    Head of the files

    Not sure if this is relevant, but the text content of both files begin like that :

    mobile_qcif_7.5fps.y4m
    
YUV4MPEG2 W176 H144 F15:2 Ip A128:117
    
FRAME
    

    
small.y4m (invalid)
    
YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C420mpeg2 XYSCSS=420MPEG2
    
FRAME

    Additional experiment

    Taking the sample mobile_qcif_7.5fps.y4m, turning it into a .mp4 file and then back into a .y4m produces an invalid file (at least for Chrome).

    Answer to comments in the answer of @SirDarius

    Following the suggestion of @SirDarius ; I tried the following commands.
    They failed to produce a valid file.

    # [COMMAND]   # [RESULT] [HEADER]
    
ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -pix_fmt yuv444p -y small_yuv444p.y4m   # KO YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C444 XYSCSS=444
    
ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -pix_fmt yuv422p -y small_yuv422p.y4m   # KO YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C422 XYSCSS=422
    
ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -pix_fmt yuv420p -y small_yuv420p.y4m   # KO YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C420mpeg2 XYSCSS=420MPEG2
    
ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -pix_fmt yuv411p -y small_yuv411p.y4m   # KO   YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C411 XYSCSS=411
    

    
ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -strict -1 -pix_fmt yuv420p9 -y small_yuv420p9.y4m   # KO YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C420p9 XYSCSS=420P9
    
ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -strict -1 -pix_fmt yuv420p12 -y small_yuv420p12.y4m # KO YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C420p12 XYSCSS=420P12
    
ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -strict -1 -pix_fmt yuv420p14 -y small_yuv420p14.y4m # KO YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C420p14 XYSCSS=420P14
    
ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -strict -1 -pix_fmt yuv420p16 -y small_yuv420p16.y4m # KO YUV4MPEG2 W560 H320 F15:2 Ip A0:0 C420p16 XYSCSS=420P16

    When trying other formats (like yuv420p12be, which was in the output of -pix_fmts), I had the following output (hence my previous trials) :

    $  ffmpeg -i small.mp4 -vf fps=7.5 -an -c:v rawvideo -f yuv4mpegpipe -pix_fmt yuv420p12be -y small_yuv420p12be.y4m 
    
ffmpeg version N-68884-g3ebd76a Copyright (c) 2000-2015 the FFmpeg developers
    
  built on Jan  6 2015 11:03:21 with gcc 4.8 (Ubuntu/Linaro 4.8.1-10ubuntu9)
    
  configuration: 
    
  libavutil      54. 16.100 / 54. 16.100
    
  libavcodec     56. 19.100 / 56. 19.100
    
  libavformat    56. 18.100 / 56. 18.100
    
  libavdevice    56.  3.100 / 56.  3.100
    
  libavfilter     5.  6.100 /  5.  6.100
    
  libswscale      3.  1.101 /  3.  1.101
    
  libswresample   1.  1.100 /  1.  1.100
    
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x21d0220] overread end of atom 'colr' by 1 bytes
    
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'small.mp4':
    
  Metadata:
    
    major_brand     : mp42
    
    minor_version   : 0
    
    compatible_brands: mp42isomavc1
    
    creation_time   : 2010-03-20 21:29:11
    
    encoder         : HandBrake 0.9.4 2009112300
    
  Duration: 00:00:05.57, start: 0.000000, bitrate: 551 kb/s
    
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p(tv, bt709), 560x320, 465 kb/s, 30 fps, 30 tbr, 90k tbn, 60 tbc (default)
    
    Metadata:
    
      creation_time   : 2010-03-20 21:29:11
    
      encoder         : JVT/AVC Coding
    
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 83 kb/s (default)
    
    Metadata:
    
      creation_time   : 2010-03-20 21:29:11
    
[yuv4mpegpipe @ 0x21d8180] ERROR: yuv4mpeg can only handle yuv444p, yuv422p, yuv420p, yuv411p and gray8 pixel formats. And using 'strict -1' also yuv444p9, yuv422p9, yuv420p9, yuv444p10, yuv422p10, yuv420p10, yuv444p12, yuv422p12, yuv420p12, yuv444p14, yuv422p14, yuv420p14, yuv444p16, yuv422p16, yuv420p16 and gray16 pixel formats. Use -pix_fmt to select one.
    
Output #0, yuv4mpegpipe, to 'small_yuv420p12be.y4m':
    
  Metadata:
    
    major_brand     : mp42
    
    minor_version   : 0
    
    compatible_brands: mp42isomavc1
    
    encoder         : Lavf56.18.100
    
    Stream #0:0(und): Video: rawvideo ([12][11]3Y / 0x59330B0C), yuv420p12be, 560x320, q=2-31, 200 kb/s, 7.50 fps, 7.50 tbn, 7.50 tbc (default)
    
    Metadata:
    
      creation_time   : 2010-03-20 21:29:11
    
      encoder         : Lavc56.19.100 rawvideo
    
Stream mapping:
    
  Stream #0:0 -> #0:0 (h264 (native) -> rawvideo (native))
    
Could not write header for output file #0 (incorrect codec parameters ?): Input/output error

    After that, I also tried to edit with an hexadecimal editor (bless) the small_yuv420p.y4m file. I replace C420mpeg2 by C420, and the file was accepted by Chrome.
    What does the number in 420p[number] correspond to ? It is not explained there.
    Is there any way to make ffmpeg output this kind of header files ?

    @SirDarius, thank you again for your help.

    The question

    (in case you forgot after this text blob)

    How can I convert the small.mp4 into a small.y4m file that has the same properties as the mobile_qcif_7.5fps.y4m file ?

  • Code library for image processing [on hold]

    1er septembre 2014, par user3928079

    Dear Stack Overflow Users,

    I am looking to create my programming portfolio as a graduate of Kennesaw State University by July 2015, when I graduate. I want to create at least 3 cross platform programs related to video or animation. In the package there will be a program for playing video and music files, a program for converting video and music files, and either a program upscaling video and image files or a program that helps animators create animation like Flipbook Pro. Since Java is cross platform, and Java is the language I’m more comfortable with, I’ll develop the software in Java, unless of course Python is cross platform as well. May you please recommend me some image processing libraries that will help me accomplish the development of these types of software programs. For the upscaling program, an upscaling algorithm from BenVista called S-Spline Max is needed, especially since I want to preserve the detail of the image, because in upscaling, you are unable to gain new information from the original information. What are some good image processing libraries I can use. I know of OpenCV, but what do a lot of programs use, high profile or low profile, like Adobe Premiere Pro or Davinci Resolve. FFMPEG is a good video library, but can it easily accomplish what I need ? What are some others that can help me in my 11 month long quest ?

    Regards,

    Jordan White

  • Révision 20982 : Report de r20981

    18 novembre 2013, par kent1 -

    Un filtre |saison_annee pour afficher des "Printemps 2014" ou "Été 2015", associé à une chaîne de langue pour gérer les cas spécifiques entre les langues

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