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  • 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 (...)

  • 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 (...)

  • 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 (2398)

  • Rate-Control management in ffmpeg

    28 février 2014, par alexbuisson

    Hi I try to understand how ffmpeg wrap its rc_max_rate parameters to the x264 parameters
    and I'm wondering what the following code means ? It's a piece of code coming from ffmpeg/libavcodec/mpeg_video_enc.c but the commit log is not explicit and I don't know from where those Magic Number come from !

    So if you have an idea or an URL that can explain why those formula where implemented, it will be useful.

    if (avctx->rc_max_rate && !avctx->rc_buffer_size) {
    
        switch(avctx->codec_id) {
    
        case AV_CODEC_ID_MPEG1VIDEO:
    
        case AV_CODEC_ID_MPEG2VIDEO:
    
            avctx->rc_buffer_size = FFMAX(avctx->rc_max_rate, 15000000) * 112L / 15000000 * 16384;
    
            break;
    
        case AV_CODEC_ID_MPEG4:
    
        case AV_CODEC_ID_MSMPEG4V1:
    
        case AV_CODEC_ID_MSMPEG4V2:
    
        case AV_CODEC_ID_MSMPEG4V3:
    
            if       (avctx->rc_max_rate >= 15000000) {
    
                avctx->rc_buffer_size = 320 + (avctx->rc_max_rate - 15000000L) * (760-320) / (38400000 - 15000000);
    
            } else if(avctx->rc_max_rate >=  2000000) {
    
                avctx->rc_buffer_size =  80 + (avctx->rc_max_rate -  2000000L) * (320- 80) / (15000000 -  2000000);
    
            } else if(avctx->rc_max_rate >=   384000) {
    
                avctx->rc_buffer_size =  40 + (avctx->rc_max_rate -   384000L) * ( 80- 40) / ( 2000000 -   384000);
    
            } else
    
                avctx->rc_buffer_size = 40;
    
            avctx->rc_buffer_size *= 16384;
    
            break;
    
        }
    
        if (avctx->rc_buffer_size) {
    
            av_log(avctx, AV_LOG_INFO, "Automatically choosing VBV buffer size of %d kbyte\n", avctx->rc_buffer_size/8192);
    
        }
    
    }

  • Drop libxvid rate control support for mpegvideo encoding

    3 décembre 2016, par Diego Biurrun
    Drop libxvid rate control support for mpegvideo encoding

    The feature has outlived is usefulness and complicates the code.
    • [DBH] libavcodec/Makefile
    • [DBH] libavcodec/libxvid.c
    • [DBH] libavcodec/libxvid.h
    • [DBH] libavcodec/libxvid_rc.c
    • [DBH] libavcodec/mpegvideo.h
    • [DBH] libavcodec/mpegvideo_enc.c

  • how to fix nvidia hevc transcoding problem

    25 novembre 2019, par Dlniya Dlzar

    we are using FFmpeg for media broadcasting DVB-T2
    the structure is like that :

    [ source h264 (multicast) >> FFmpeg h265 >> scrambler ]

    we are using Nvidia GPU for transcoding

    the problem is, when we transcode to H265 there is an issue when we play the video.
    it is like cc error or maybe muxing issue, we don’t know, what we know is, the stream has lagging every few mins.
    we played the output stream by FFmpeg again

    /root/bin/ffmpeg -v error -i udp://lo@127.0.0.1:5000 -f null - 2>error.log

    we got this

    [hevc @ 0x2610b40] PPS id out of range: 0
    
    Last message repeated 35 times
    
[hevc @ 0x2604a80] Could not find ref with POC 21

    and here is our FFmpeg command line example for transcoding

    /root/bin/ffmpeg -re -y -vsync 0 -hwaccel cuvid -c:v h264_cuvid  -deint 2  -drop_second_field 1 -surfaces 10 -fflags discardcorrupt+genpts+nobuffer -i   "udp://227.30.40.4:1234?localaddr=192.168.2.55&overrun_nonfatal=1&&fifo_size=50000000" -map 0:p:352 -af aresample=async=1  -acodec aac -ac 1 -strict -2  -vcodec hevc_nvenc  -g 40  -b:v 2300k -minrate 2300k -maxrate 2300k -bufsize 2300k -preset hq -metadata service_provider="ISTAR MEDIA" -metadata service_name="KURDMAX" -flags cgop -sc_threshold 500  -f mpegts -muxrate 2700k  -y  "udp://227.2.2.6:1234?localaddr=192.168.2.55&fifo_buffer=50000000&overrun_nonfatal_option=1&bitrate=2700000&burst_bits=2700000&pkt_size=1316" 2> /var/log/ffmpeg/kurdmax.txt

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