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  • Submit bugs and patches

    13 avril 2011

    Unfortunately a software is never perfect.
    If you think you have found a bug, report it using our ticket system. Please to help us to fix it by providing the following information : the browser you are using, including the exact version as precise an explanation as possible of the problem if possible, the steps taken resulting in the problem a link to the site / page in question
    If you think you have solved the bug, fill in a ticket and attach to it a corrective patch.
    You may also (...)

  • 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 (...)

  • Dépôt de média et thèmes par FTP

    31 mai 2013, par

    L’outil MédiaSPIP traite aussi les média transférés par la voie FTP. Si vous préférez déposer par cette voie, récupérez les identifiants d’accès vers votre site MédiaSPIP et utilisez votre client FTP favori.
    Vous trouverez dès le départ les dossiers suivants dans votre espace FTP : config/ : dossier de configuration du site IMG/ : dossier des média déjà traités et en ligne sur le site local/ : répertoire cache du site web themes/ : les thèmes ou les feuilles de style personnalisées tmp/ : dossier de travail (...)

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  • mmsh:_implement a minimal mmsh_seek() so the stream position can be found out.

    31 octobre 2011, par Michael Niedermayer

    mmsh:_implement a minimal mmsh_seek() so the stream position can be found out.

  • ffmpeg poor YUV to RGB in sws_scale() (was : ffmpeg blocky chroma decoding)

    12 septembre 2017, par noiseshaper

    I’m using ffmpeg-3.2.4-win32, static and dev versions from zeranoe page, to decode some h264 mp4 videos I have created with x264 encoder. The videos have lots of static zones, 2d videogame type.

    When I decode their frames using either ffmpeg.exe or avcodec_decode_video2() API function, I get poor chroma resolution, blocky and quite visible in the static zones of the video (edit : avcodec_decode_video2() returns correct YUV, the problem is the YUV->RGB conversion, see my own answer below).

    With ffmpeg.exe I get poor chroma only if I output the frames to png, but if I output them to jpg, chroma seems much better (edit : this is due to poor YUV to RGB conversion of ffmpeg’s sws_scale()).

    Here is an example of the same frame obtained from a mp4 video created with a static image, the output frame is zoomed in to clearly see the effect.

    https://drive.google.com/file/d/0B5KI1D-N1kHpV3lGaERJRjNkcms/view

    1 : Original frame before compressing.

    2 : YUV 4:2:0 conversion before compressing

    3 : Video output from MPC HC + LAV decoder. This is YUV decoded output.

    4 : Video frames decoded with ffmpeg.exe to jpeg, quality is mostly ok, just some jpeg macroblocking is visible.

    5 : Video frames decoded with ffmpeg.exe to png, very blocky chroma. This is RGB output, using avcodec_decode_video2() and sws_scale() conversion to RGB produces the same blocky chroma.

    The command lines for decoding the frames to jpg and png are these :

    ffmpeg -i testcase.mp4 -vframes 5 -qscale:v 2 output%03d.jpg

    ffmpeg -i testcase.mp4 -vframes 5 output%03d.png

    You can download mp4 and bat files that showcase the effect here :

    https://drive.google.com/drive/folders/0B5KI1D-N1kHpcUdGd2IyM2pXMTg

    I have tried with ffmpeg 3.2, but same thing happens.

  • libavcodec/mpeg12dec : Check input for minimal frame size

    4 septembre 2019, par Michael Niedermayer
    libavcodec/mpeg12dec : Check input for minimal frame size

    Fixes : Timeout (35sec -> 6sec)
    
Fixes : 16901/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEGVIDEO_fuzzer-5729024726269952
    
Fixes : 16901/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEGVIDEO_fuzzer-5642388592132096
    

    Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
    
Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
    • [DH] libavcodec/mpeg12dec.c

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