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  • Publier sur MédiaSpip

    13 juin 2013

    Puis-je poster des contenus à partir d’une tablette Ipad ?
    Oui, si votre Médiaspip installé est à la version 0.2 ou supérieure. Contacter au besoin l’administrateur de votre MédiaSpip pour le savoir

  • List of compatible distributions

    26 avril 2011, par

    The table below is the list of Linux distributions compatible with the automated installation script of MediaSPIP. Distribution nameVersion nameVersion number Debian Squeeze 6.x.x Debian Weezy 7.x.x Debian Jessie 8.x.x Ubuntu The Precise Pangolin 12.04 LTS Ubuntu The Trusty Tahr 14.04
    If you want to help us improve this list, you can provide us access to a machine whose distribution is not mentioned above or send the necessary fixes to add (...)

  • Automated installation script of MediaSPIP

    25 avril 2011, par

    To overcome the difficulties mainly due to the installation of server side software dependencies, an "all-in-one" installation script written in bash was created to facilitate this step on a server with a compatible Linux distribution.
    You must have access to your server via SSH and a root account to use it, which will install the dependencies. Contact your provider if you do not have that.
    The documentation of the use of this installation script is available here.
    The code of this (...)

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  • FFmpeg returning an error - What does it mean ?

    19 mars 2013, par user1031947

    I am using FFmpeg, libmp3lame & libx264 along with the node fluent-ffmpeg module. This is my first foray into processing uploaded videos.

    From node, I use the following code to process an uploaded video :

    var proc = new ffmpeg({ source: src, nolog: true })
    
    .usingPreset( "podcast" )
    
    .withAudioCodec( "libmp3lame" )
    
    .saveToFile( dest, function( retcode, err ){
    
         if( err ) throw err;
    
         ...
    
    });

    When I try to process a video, this fails with the following error, which I don't understand. I am hoping someone here can help point me in the right direction. Thanks !

    > ffmpeg version 0.8.5-6:0.8.5-1, Copyright (c) 2000-2012 the Libav
    
> developers   built on Jan 13 2013 12:05:48 with gcc 4.7.2
    
> *** THIS PROGRAM IS DEPRECATED *** This program is only provided for compatibility and will be removed in a future release. Please use
    
> avconv instead.
    
> 
    
> Seems stream 0 codec frame rate differs from container frame rate:
    
> 5994.00 (5994/1) -> 29.97 (2997/100) Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
    
> '/home/ssp/resources/tmp/32111bf4217e87c23328ec81c56c7d02':  
    
> Metadata:
    
>     major_brand     : M4VP
    
>     minor_version   : 1
    
>     compatible_brands: M4VPM4A mp42isom
    
>     creation_time   : 2008-08-26 17:28:47   Duration: 00:00:08.01, start: 0.000000, bitrate: 944 kb/s
    
>     Stream #0.0(eng): Video: h264 (Constrained Baseline), yuv420p, 480x272, 815 kb/s, 29.97 fps, 29.97 tbr, 2997 tbn, 5994 tbc
    
>     Metadata:
    
>       creation_time   : 2008-08-26 17:28:47
    
>     Stream #0.1(eng): Audio: aac, 44100 Hz, stereo, s16, 124 kb/s
    
>     Metadata:
    
>       creation_time   : 2008-08-26 17:28:47 [buffer @ 0xb685a0] w:480 h:272 pixfmt:yuv420p [scale @ 0xb63280] w:480 h:272 fmt:yuv420p ->
    
> w:320 h:176 fmt:yuv420p flags:0x4 [libx264 @ 0xb67c20] VBV maxrate
    
> unspecified, assuming CBR [libx264 @ 0xb67c20] using cpu capabilities:
    
> MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 AVX [libx264 @ 0xb67c20]
    
> profile Main, level 1.3 Output #0, m4v, to
    
> '/home/ssp/resources/users/11/026468c8f4ea1beee0a585ebc2208137.m4v':  
    
> Metadata:
    
>     major_brand     : M4VP
    
>     minor_version   : 1
    
>     compatible_brands: M4VPM4A mp42isom
    
>     creation_time   : 2008-08-26 17:28:47
    
>     encoder         : Lavf53.21.1
    
>     Stream #0.0(eng): Video: libx264, yuv420p, 320x176, q=10-51, 512 kb/s, 90k tbn, 29.97 tbc
    
>     Metadata:
    
>       creation_time   : 2008-08-26 17:28:47
    
>     Stream #0.1(eng): Audio: libmp3lame, 44100 Hz, 1 channels, s16, 128 kb/s
    
>     Metadata:
    
>       creation_time   : 2008-08-26 17:28:47 Stream mapping:   Stream #0.0 -> #0.0   Stream #0.1 -> #0.1 Press ctrl-c to stop encoding frame=  240 fps=154 q=11.0 Lsize=     642kB time=7.97 bitrate=
    
> 659.3kbits/s     video:516kB audio:126kB global headers:0kB muxing overhead 0.000000% frame I:1     Avg QP:15.35  size:  9995 [libx264 @
    
> 0xb67c20] frame P:77    Avg QP:13.25  size:  5419 [libx264 @ 0xb67c20]
    
> frame B:162   Avg QP:18.31  size:   625 [libx264 @ 0xb67c20]
    
> consecutive B-frames:  2.5% 12.5% 30.0% 55.0% [libx264 @ 0xb67c20] mb
    
> I  I16..4:  9.1%  0.0% 90.9% [libx264 @ 0xb67c20] mb P  I16..4:  2.1% 
    
> 0.0%  2.8%  P16..4: 18.0% 29.9% 44.8%  0.0%  0.0%    skip: 2.3% [libx264 @ 0xb67c20] mb B  I16..4:  0.1%  0.0%  0.0%  B16..8: 35.2%
    
> 20.2%  1.9%  direct:14.5%  skip:28.1%  L0:26.3% L1:38.1% BI:35.6% [libx264 @ 0xb67c20] coded y,uvDC,uvAC intra: 83.7% 91.7% 84.7% inter:
    
> 27.7% 43.4% 13.9% [libx264 @ 0xb67c20] i16 v,h,dc,p: 20% 29% 42%  9% [libx264 @ 0xb67c20] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 29% 20%  4% 
    
> 8%  6%  9%  3%  4% [libx264 @ 0xb67c20] i8c dc,h,v,p: 60% 19% 16%  5%
    
> [libx264 @ 0xb67c20] Weighted P-Frames: Y:2.6% UV:0.0% [libx264 @
    
> 0xb67c20] ref P L0: 75.6% 13.5%  8.0%  2.8%  0.1% [libx264 @ 0xb67c20]
    
> ref B L0: 94.5%  5.5% [libx264 @ 0xb67c20] kb/s:528.00

  • What Every Programmer Should Know

    24 décembre 2012, par Multimedia Mike — General

    During my recent effort to force myself to understand Unicode and modern text encoding/processing, I was reminded that this is something that “every programmer should just know”, an idea that comes up every so often, usually in relation to a subject in which the speaker is already an expert. One of the most absurd examples I ever witnessed was a blog post along the lines of “What every working programmer ought to know about [some very specific niche of enterprise-level Java programming]“. I remember reading through the article and recognizing that I had almost no knowledge of the material. Disturbing, since I am demonstrably a “working programmer”.

    For fun, I queried the googles on the matter of what ever programmer ought to know.

    Specific Topics
    Here is what every programmer should know about : Unicode, time, memory (simple), memory (extremely in-depth), regular expressions, search engine optimization, floating point, security, basic number theory, race conditions, managed C++, VIM commands, distributed systems, object-oriented design, latency numbers, rate monotonic algorithm, merging branches in Mercurial, classes of algorithms, and human names.

    Broader Topics
    20 subjects every programmer should know, 97 things every programmer should know, 12 things every programmer should know, things every programmer should know (27 items), 10 papers every programmer should read at least twice, 10 things every programmer should know for their first job.

    Meanwhile, I remain fond of this xkcd comic whose mouseover text describes all that a person genuinely needs to know. Still, the new year is upon us, a time when people often make commitments to bettering themselves, and it couldn’t hurt (much) to at least skim some of the lists and find out what you never knew that you never knew.

    What About Multimedia ?
    Reading the foregoing (or the titles of the foregoing pieces), I naturally wonder if I should write something about what every programmer should know about multimedia. I think it would look something like a multimedia programming FAQ. These are some items that I can think of :

    1. YUV : The other colorspace (since most programmers are only familiar with RGB and have no idea what to make of the YUV that comes out of most video decoding APIs)
    2. Why you can’t easily seek randomly to any specific frame in a video file (keyframe/interframe discussion and their implications)
    3. Understand your platform before endeavoring to implement multimedia software (modern platforms, particularly mobile platforms, probably provide everything you need in the native APIs and there is likely little reason to compile libavcodec for the platform)
    4. Difference between containers and codecs (longstanding item, but I would argue it’s less relevant these days due to standardization on the MPEG — MP4/H.264/AAC — stack)
    5. What counts as a multimedia standard in this day and age (comparing the foregoing MPEG stack with the WebM/VP8/Vorbis stack)
    6. Trade-offs to consider when engineering a multimedia solution
    7. Optimization doesn’t always work the way you think it does (not everything touted as a massive speed-up in the world of computing — whether it be multithreaded CPUs, GPGPUs, new SIMD instruction sets — will necessarily be applicable to multimedia processing)
    8. A practical guide to legal issues would not be amiss
    9.  ???

    What other items count as “something multimedia-related that every programmer should know” ?

  • Why does FFMPEG report the wrong duration ?

    27 avril 2013, par Adrian Lynch

    I have an oldish build of FFMPEG that I can't easily change.

    We use FFMPEG to find the duration of video and sound files. So far it has been working wonderfully.

    Recently on an uploaded file, FFMPEG has reported a 30 second file as being 5 minutes 30 seconds in length.

    Could it be something wrong with the file rather than FFMPEG ?

    If I use FFMPEG to convert to another file, the duration is restored.

    In case it matters, ffmpeg -i 'path to the file' produces :

        FFmpeg version Sherpya-r15618, Copyright (c) 2000-2008 Fabrice Bellard, et al.
      libavutil     49.11. 0 / 49.11. 0
      libavcodec    52. 0. 0 / 52. 0. 0
      libavformat   52.22. 1 / 52.22. 1
      libavdevice   52. 1. 0 / 52. 1. 0
      libswscale     0. 6. 1 /  0. 6. 1
      libpostproc   51. 2. 0 / 51. 2. 0
      built on Oct 14 2008 23:43:47, gcc : 4.2.5 20080919 (prerelease) [Sherpya]
    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'H :\path\to\file.mov' :
      Duration : 00:05:35.00, start : 0.000000, bitrate : 1223 kb/s
        Stream #0.0(eng) : Audio : aac, 44100 Hz, stereo, s16
        Stream #0.1(eng) : Video : h264, yuv420p, 720x576, 25.00 tb(r)
    Must supply at least one output file

    It's that very command I use to then extract the duration with RegEx.

    Does anyone have a nice application that can do what I'm trying above but get it right 100% of the time ?

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