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  • HTML5 audio and video support

    13 avril 2011, par

    MediaSPIP uses HTML5 video and audio tags to play multimedia files, taking advantage of the latest W3C innovations supported by modern browsers.
    The MediaSPIP player used has been created specifically for MediaSPIP and can be easily adapted to fit in with a specific theme.
    For older browsers the Flowplayer flash fallback is used.
    MediaSPIP allows for media playback on major mobile platforms with the above (...)

  • Les tâches Cron régulières de la ferme

    1er décembre 2010, par

    La gestion de la ferme passe par l’exécution à intervalle régulier de plusieurs tâches répétitives dites Cron.
    Le super Cron (gestion_mutu_super_cron)
    Cette tâche, planifiée chaque minute, a pour simple effet d’appeler le Cron de l’ensemble des instances de la mutualisation régulièrement. Couplée avec un Cron système sur le site central de la mutualisation, cela permet de simplement générer des visites régulières sur les différents sites et éviter que les tâches des sites peu visités soient trop (...)

  • Les formats acceptés

    28 janvier 2010, par

    Les commandes suivantes permettent d’avoir des informations sur les formats et codecs gérés par l’installation local de ffmpeg :
    ffmpeg -codecs ffmpeg -formats
    Les format videos acceptés en entrée
    Cette liste est non exhaustive, elle met en exergue les principaux formats utilisés : h264 : H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 m4v : raw MPEG-4 video format flv : Flash Video (FLV) / Sorenson Spark / Sorenson H.263 Theora wmv :
    Les formats vidéos de sortie possibles
    Dans un premier temps on (...)

Sur d’autres sites (6046)

  • aaccoder : add a new perceptual noise substitution implementation

    2 juillet 2015, par Rostislav Pehlivanov
    aaccoder : add a new perceptual noise substitution implementation

    This commit finalizes the PNS implementation previously added to the encoder
    
by moving it to a seperate function search_for_pns() and thus making it
    
coder-generic. This new implementation makes use of the spread field of
    
the psy bands and the lambda quality feedback paremeter. The spread of the
    
spectrum in a band prevents PNS from being used excessively and thus preserve
    
more phase information in high frequencies.  The lambda parameter allows
    
the number of PNS-marked bands to vary based on the lambda parameter and the
    
amount of bits available, making better choices on which bands are to be marked
    
as noise. Comparisons with the previous PNS implementation can be found
    
here : https://trac.ffmpeg.org/attachment/wiki/Encode/AAC/
    

    This is V2 of the patch, the changes from the previous version being that this
    
version uses the new band->spread metric from aacpsy and normalizes the
    
energy using the group size. These changes were suggested by Claudio Freire
    
on the mailing list. Another change is the use of lambda to alter the
    
frequency threshold. This change makes the actual threshold frequencies
    
vary between +-2Khz of what’s specified, depending on frame encoding performance.
    

    Reviewed-by : Claudio Freire <klaussfreire@gmail.com>
    
Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
    • [DH] libavcodec/aaccoder.c
    • [DH] libavcodec/aacenc.c
    • [DH] libavcodec/aacenc.h

  • aacenc : use the new function for setting special band scalefactor indices

    2 juillet 2015, par Rostislav Pehlivanov
    aacenc : use the new function for setting special band scalefactor indices

    This commit enables the function added with commit 7c10b87 and uses that
    
new function for setting any special scalefactor indices. This commit does
    
not change the behaviour of the encoder since no bands are being marked as
    
either NOISE_BT(due to the previous PNS implementation removed in the
    
previous commit) or INTENSITY_BT2/INTENSITY_BT.
    

    Reviewed-by : Claudio Freire <klaussfreire@gmail.com>
    
Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
    • [DH] libavcodec/aaccoder.c
    • [DH] libavcodec/aacenc.c
    • [DH] libavcodec/aacenc.h

  • AAC Encoder : clipping avoidance

    21 juillet 2015, par Claudio Freire
    AAC Encoder : clipping avoidance

    Avoid clipping due to quantization noise to produce audible
    
artifacts, by detecting near-clipping signals and both attenuating
    
them a little and encoding escape-encoded bands (usually the
    
loudest) rounding towards zero instead of nearest, which tends to
    
decrease overall energy and thus clipping.
    

    Currently fate tests measure numerical error so this change makes
    
tests using asynth (which are near clipping) report higher error
    
not less, because of window attenuation. Yet, they sound better,
    
not worse (albeit subtle, other samples aren’t subtle at all).
    
Only measuring psychoacoustically weighted error would make for
    
a representative test, so that will be left for a future patch.
    

    Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
    • [DH] libavcodec/aac.h
    • [DH] libavcodec/aaccoder.c
    • [DH] libavcodec/aacenc.c
    • [DH] libavcodec/aacenc.h
    • [DH] libavcodec/aacpsy.c
    • [DH] libavcodec/psymodel.h
    • [DH] tests/fate/aac.mak

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