Recherche avancée

Médias (91)

Autres articles (57)

  • Websites made ​​with MediaSPIP

    2 mai 2011, par

    This page lists some websites based on MediaSPIP.

  • Creating farms of unique websites

    13 avril 2011, par

    MediaSPIP platforms can be installed as a farm, with a single "core" hosted on a dedicated server and used by multiple websites.
    This allows (among other things) : implementation costs to be shared between several different projects / individuals rapid deployment of multiple unique sites creation of groups of like-minded sites, making it possible to browse media in a more controlled and selective environment than the major "open" (...)

  • Contribute to a better visual interface

    13 avril 2011

    MediaSPIP is based on a system of themes and templates. Templates define the placement of information on the page, and can be adapted to a wide range of uses. Themes define the overall graphic appearance of the site.
    Anyone can submit a new graphic theme or template and make it available to the MediaSPIP community.

Sur d’autres sites (6569)

  • 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.

  • lavfi/qsvvpp : use the right mfxFrameInfo when dynamic frame pool is used

    8 mai 2024, par Haihao Xiang
    lavfi/qsvvpp : use the right mfxFrameInfo when dynamic frame pool is used

    Signed-off-by : Haihao Xiang <haihao.xiang@intel.com>
    • [DH] libavfilter/qsvvpp.c

  • lavu/hwcontext_qsv : add support for dynamic frame pool in qsv_map_to

    8 mai 2024, par Haihao Xiang
    lavu/hwcontext_qsv : add support for dynamic frame pool in qsv_map_to

    Make it work with the source which has a dynamic frame pool.
    

    Signed-off-by : Haihao Xiang <haihao.xiang@intel.com>
    • [DH] libavutil/hwcontext_qsv.c

Navigation