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Autres articles (57)

  • MediaSPIP 0.1 Beta version

    25 avril 2011, par

    MediaSPIP 0.1 beta is the first version of MediaSPIP proclaimed as "usable".
    The zip file provided here only contains the sources of MediaSPIP in its standalone version.
    To get a working installation, you must manually install all-software dependencies on the server.
    If you want to use this archive for an installation in "farm mode", you will also need to proceed to other manual (...)

  • MediaSPIP version 0.1 Beta

    16 avril 2011, par

    MediaSPIP 0.1 beta est la première version de MediaSPIP décrétée comme "utilisable".
    Le fichier zip ici présent contient uniquement les sources de MediaSPIP en version standalone.
    Pour avoir une installation fonctionnelle, il est nécessaire d’installer manuellement l’ensemble des dépendances logicielles sur le serveur.
    Si vous souhaitez utiliser cette archive pour une installation en mode ferme, il vous faudra également procéder à d’autres modifications (...)

  • Amélioration de la version de base

    13 septembre 2013

    Jolie sélection multiple
    Le plugin Chosen permet d’améliorer l’ergonomie des champs de sélection multiple. Voir les deux images suivantes pour comparer.
    Il suffit pour cela d’activer le plugin Chosen (Configuration générale du site > Gestion des plugins), puis de configurer le plugin (Les squelettes > Chosen) en activant l’utilisation de Chosen dans le site public et en spécifiant les éléments de formulaires à améliorer, par exemple select[multiple] pour les listes à sélection multiple (...)

Sur d’autres sites (3549)

  • aacenc_pred : rework the way prediction is done

    29 août 2015, par Rostislav Pehlivanov
    aacenc_pred : rework the way prediction is done
    

    This commit completely alters the algorithm of prediction.
    The original commit which introduced prediction was completely
    incorrect to even remotely care about what the actual coefficients
    contain or whether any options were enabled. Not my actual fault.

    This commit treats prediction the way the decoder does and expects
    to do : like lossy encryption. Everything related to prediction now
    happens at the very end but just before quantization and encoding
    of coefficients. On the decoder side, prediction happens before
    anything has had a chance to even access the coefficients.

    Also the original implementation had problems because it actually
    touched the band_type of special bands which already had their
    scalefactor indices marked and it’s a wonder the asserion wasn’t
    triggered when transmitting those.

    Overall, this now drastically increases audio quality and you should
    think about enabling it if you don’t plan on playing anything encoded
    on really old low power ultra-embedded devices since they might not
    support decoding of prediction or AAC-Main. Though the specifications
    were written ages ago and as times change so do the FLOPS.

    Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>

    • [DH] libavcodec/aac.h
    • [DH] libavcodec/aaccoder.c
    • [DH] libavcodec/aacenc.c
    • [DH] libavcodec/aacenc.h
    • [DH] libavcodec/aacenc_pred.c
    • [DH] libavcodec/aacenc_pred.h
  • aacenc : implement Intensity Stereo encoding support

    2 juillet 2015, par Rostislav Pehlivanov
    aacenc : implement Intensity Stereo encoding support
    

    This commit implements intensity stereo coding support
    to the native aac encoder. This is a way to increase the efficiency
    of the encoder by zeroing the right channel’s spectral coefficients
    (in a channel pair) and rederiving them in the decoder using information
    from the scalefactor indices of special band types. This commit
    confomrs to the official ISO 13818-7 specifications, although due to
    their ambiguity certain deviations have been taken to ensure maximum
    sound quality. This commit has been extensively tested and has shown
    to not result in audiable audio artifacts unless in extreme cases.
    This commit also adds an option, aac_is, which has the value of
    0 by default. Intensity Stereo is part of the scalable aac profile
    and is thus non-default.

    The way IS coding works is that it rederives the right channel’s
    spectral coefficients from the left channel via the scalefactor
    index values left in the right channel. Since an entire band’s
    spectral coefficients do not need to be coded, the encoder’s
    efficiency jumps up and it unzeroes some high frequency values
    which it previously did not have enough bits to encode. That way
    less information is lost than the information lost by rederiving
    the spectral coefficients with some error. This is why the
    filesize of files encoded with IS do not decrease significantly.
    Users wishing that IS coding should reduce filesize are expected
    to reduce their encoding bitrates appropriately.

    This is V2 of the commit. The old version did not mark ms_mask as
    0 since M/S and IS coding are incompactible, which resulted in
    distortions with M/S coding enabled. This version also improves
    phase detection by measuring it for every spectral coefficient in
    the band and using a simple majority rule to determine whether the
    coefficients are in or out of phase. Also, the energy values per
    spectral coefficient were changed as to reflect the
    official specifications.

    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
  • avcodec/pngdec : Copy IHDR & plte state from last thread

    29 juin 2015, par Michael Niedermayer
    avcodec/pngdec : Copy IHDR & plte state from last thread
    

    Previously these chunks where parsed again for each frame with threads
    but not without leading to a different path and the potential for
    inconsistencies

    This also removes a related special case from decode_ihdr_chunk()

    Signed-off-by : Michael Niedermayer <michaelni@gmx.at>

    • [DH] libavcodec/pngdec.c