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Autres articles (4)

  • Supporting all media types

    13 avril 2011, par

    Unlike most software and media-sharing platforms, MediaSPIP aims to manage as many different media types as possible. The following are just a few examples from an ever-expanding list of supported formats : images : png, gif, jpg, bmp and more audio : MP3, Ogg, Wav and more video : AVI, MP4, OGV, mpg, mov, wmv and more text, code and other data : OpenOffice, Microsoft Office (Word, PowerPoint, Excel), web (html, CSS), LaTeX, Google Earth and (...)

  • Keeping control of your media in your hands

    13 avril 2011, par

    The vocabulary used on this site and around MediaSPIP in general, aims to avoid reference to Web 2.0 and the companies that profit from media-sharing.
    While using MediaSPIP, you are invited to avoid using words like "Brand", "Cloud" and "Market".
    MediaSPIP is designed to facilitate the sharing of creative media online, while allowing authors to retain complete control of their work.
    MediaSPIP aims to be accessible to as many people as possible and development is based on expanding the (...)

  • Le plugin : Podcasts.

    14 juillet 2010, par

    Le problème du podcasting est à nouveau un problème révélateur de la normalisation des transports de données sur Internet.
    Deux formats intéressants existent : Celui développé par Apple, très axé sur l’utilisation d’iTunes dont la SPEC est ici ; Le format "Media RSS Module" qui est plus "libre" notamment soutenu par Yahoo et le logiciel Miro ;
    Types de fichiers supportés dans les flux
    Le format d’Apple n’autorise que les formats suivants dans ses flux : .mp3 audio/mpeg .m4a audio/x-m4a .mp4 (...)

Sur d’autres sites (3524)

  • issue in converting a stream of images that is jittery and lossy into a video (using ffmpeg or otherwise)

    17 mars 2019, par ksridhar

    i have a program that is the source for png images that are sent out on its stdout. this program is prone to lose images as well have jitter (not deliver them on time precisely i.e. 25 frames/sec).

    i tried the following with ffmpeg

    image_streamer.sh | ffmpeg -vcodec png -i - -vf fps=25 -vcodec libx264 -y foo.mp4.

    it was noticed that (a) when the input rate was wavering around 25 frames/sec with no drops the mp4 file was created fine but when (b) there were drops by the image_streamer.sh the fps filter did not duplicate images. i understand that there is no pts information in this case.

    i read several questions/answers around this issue but there we related to files and not a pipe.

    There was also a thread of conversation a long time back (https://ffmpeg.org/pipermail/ffmpeg-user/2012-December/011855.html) but it lead to a dead end.

    i am quite naive to ffmpeg. i hope that this question is not something really stupid.

  • H264 decompression/decomposition into JPG - quality issues

    5 juin 2013, par Respectech

    I'm trying to decode a 1920x1080 30fps h264 stream. Individual frames look outstanding in VLC media player (pausing the playback), but when I decode using avconv (ffmpeg has been deprecated and replaced by avconv), the frame quality is really poor by comparison (my primary complaint is blockiness).

    Here's how I am calling avconv :

    avconv -i video.h264 -s 1920x1080 -f image2 temp/images/video-%03d.jpg

    Is there a jpg output setting for avconv ? I read what I suspected were the salient parts of the avconv documentation (namely, http://libav.org/avconv.html#image2-1), and couldn't find any way to specify the output jpg quality.

    In addition, it appears avconv reads the entire stream before it starts decoding it, so if the stream is in progress, it only decodes to where the stream was when avconv started the decoding process. Is there any way around this ? In other words, if a 10-second-long stream is started at t seconds and avconv is started at t+1 seconds, avconv will only decode 1 second of the stream.

  • Revision eec3def7c5 : Modified no memory rate control. This 2-pass rate control setting allocates bit

    16 octobre 2013, par Paul Wilkins

    Changed Paths :
     Modify /vp9/encoder/vp9_onyx_if.c


     Modify /vp9/encoder/vp9_onyx_int.h


     Modify /vp9/encoder/vp9_ratectrl.c



    Modified no memory rate control.

    This 2-pass rate control setting allocates bits based
    on first pass stats to each kf group, gf group and individual
    frame but does not correct the bits left and allocation after
    each frame.

    In other words it recommends a bit allocation for each frame
    but does not try and correct any over or under spend on a
    frame over the remainder of the clip. This reduces the accuracy
    of rate control in terms of hitting an average bitrate but prevents
    problems that may arise because early frames either use to many
    or too few bits. This mode is currently more inclined to undershoot
    than overshoot (particularly at higher data rates).

    Also minor changes to rate of adaption when recode loop is not
    enabled.

    This mode is currently enabled by default for VBR.
    It gives the following % performance gains.

    derf +0.467, +1.072
    yt 2.962, 2.645
    stdhd 1.682, 1.595,
    yt-hd 2.3, 2.174

    Change-Id : I3c84a9bf8884e5b345698ff0e19187f792c2f3a0