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  • Gestion des droits de création et d’édition des objets

    8 février 2011, par

    Par défaut, beaucoup de fonctionnalités sont limitées aux administrateurs mais restent configurables indépendamment pour modifier leur statut minimal d’utilisation notamment : la rédaction de contenus sur le site modifiables dans la gestion des templates de formulaires ; l’ajout de notes aux articles ; l’ajout de légendes et d’annotations sur les images ;

  • 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 (...)

  • 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 (...)

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  • FFMPEG fix broken stream headers ?

    4 janvier 2017, par Dominic

    I have a couple of video files (.tsv) from the same recording device. One file seems to have broken headers, ffmpeg reports

    "dimensions not set"

    and

    "Could not write header for output file #0 (incorrect codec
    parameters)",

    the other is ok. Is there any way to instruct ffmpeg (or any other software that may help) to use headers / video parameters from user options or from the other file ?

    ffmpeg output for broken video :

    H:\PVR\TV> ffmpeg.exe -i "TV(152420).TSV" -vcodec copy -acodec copy "d:\TVP(152420).mp4"
    
ffmpeg version N-82966-g6993bb4 Copyright (c) 2000-2016 the FFmpeg developers
    
  built with gcc 5.4.0 (GCC)
    
  configuration: --enable-gpl --enable-version3 --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable
    
-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-li
    
bbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enabl
    
e-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-li
    
bopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --en
    
able-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable
    
-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zl
    
ib
    
  libavutil      55. 43.100 / 55. 43.100
    
  libavcodec     57. 70.100 / 57. 70.100
    
  libavformat    57. 61.100 / 57. 61.100
    
  libavdevice    57.  2.100 / 57.  2.100
    
  libavfilter     6. 68.100 /  6. 68.100
    
  libswscale      4.  3.101 /  4.  3.101
    
  libswresample   2.  4.100 /  2.  4.100
    
  libpostproc    54.  2.100 / 54.  2.100
    
[h264 @ 000000000058f040] non-existing SPS 0 referenced in buffering period
    
[h264 @ 000000000058f040] SPS unavailable in decode_picture_timing
    
[h264 @ 000000000058f040] non-existing PPS 0 referenced
    
[h264 @ 000000000058f040] non-existing SPS 0 referenced in buffering period
    
[h264 @ 000000000058f040] SPS unavailable in decode_picture_timing
    
[h264 @ 000000000058f040] non-existing PPS 0 referenced
    
[h264 @ 000000000058f040] decode_slice_header error
    
[h264 @ 000000000058f040] no frame!
    

    
/repeated a few times/
    

    
[h264 @ 000000000058f040] non-existing SPS 0 referenced in buffering period
    
[h264 @ 000000000058f040] SPS unavailable in decode_picture_timing
    
[h264 @ 000000000058f040] non-existing PPS 0 referenced
    
[h264 @ 000000000058f040] non-existing SPS 0 referenced in buffering period
    
[h264 @ 000000000058f040] SPS unavailable in decode_picture_timing
    
[h264 @ 000000000058f040] non-existing PPS 0 referenced
    
[h264 @ 000000000058f040] decode_slice_header error
    
[h264 @ 000000000058f040] no frame!
    
[mpegts @ 000000000058a9a0] DTS discontinuity in stream 5: packet 14 with DTS 8279617306, packet 15 with DTS 8590342112
    
[mpegts @ 000000000058a9a0] decoding for stream 0 failed
    
[mpegts @ 000000000058a9a0] start time for stream 4 is not set in estimate_timings_from_pts
    
[mpegts @ 000000000058a9a0] start time for stream 7 is not set in estimate_timings_from_pts
    
[mpegts @ 000000000058a9a0] PES packet size mismatch
    
    Last message repeated 3 times
    
[mpegts @ 000000000058a9a0] Could not find codec parameters for stream 0 (Video: h264 ([27][0][0][0] / 0x001B), none): u
    
nspecified size
    
Consider increasing the value for the 'analyzeduration' and 'probesize' options
    
[mpegts @ 000000000058a9a0] Could not find codec parameters for stream 6 (Unknown: none ([5][0][0][0] / 0x0005)): unknow
    
n codec
    
Consider increasing the value for the 'analyzeduration' and 'probesize' options
    
Input #0, mpegts, from 'TVP(152420).TSV':
    
  Duration: 02:40:37.93, start: 91995.111844, bitrate: 3550 kb/s
    
  Program 1
    
    Stream #0:0[0x66]: Video: h264 ([27][0][0][0] / 0x001B), none, 50 fps, 50 tbr, 90k tbn, 180k tbc
    
    Stream #0:1[0x67](pol): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 160 kb/s
    
    Stream #0:2[0x69](pol): Subtitle: dvb_teletext ([6][0][0][0] / 0x0006)
    
    Stream #0:3[0x68](qaa): Audio: eac3 (EAC3 / 0x33434145), 48000 Hz, 5.1(side), fltp, 256 kb/s
    
    Stream #0:4[0x6a](pol): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)
    
    Stream #0:5[0x6c](aux): Audio: eac3 (EAC3 / 0x33434145), 48000 Hz, stereo, fltp, 96 kb/s (visual impaired)
    
    Stream #0:6[0x6b]: Unknown: none ([5][0][0][0] / 0x0005)
    
    Stream #0:7[0x6d](eng): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)
    
  Program 2
    
  Program 21
    
  Program 31
    
  Program 32
    
  Program 33
    
  Program 34
    
  Program 35
    
[mp4 @ 00000000032cd500] dimensions not set
    
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
    
Stream mapping:
    
  Stream #0:0 -> #0:0 (copy)
    
  Stream #0:3 -> #0:1 (copy)
    
    Last message repeated 1 times

    Meanwhile, the other file from the same transmission goes through similar "no frame" messages, to finish with successful stream identification.

    [h264 @ 00000000004cf040] non-existing SPS 0 referenced in buffering period
    
[h264 @ 00000000004cf040] SPS unavailable in decode_picture_timing
    
[h264 @ 00000000004cf040] non-existing PPS 0 referenced
    
[h264 @ 00000000004cf040] non-existing SPS 0 referenced in buffering period
    
[h264 @ 00000000004cf040] SPS unavailable in decode_picture_timing
    
[h264 @ 00000000004cf040] non-existing PPS 0 referenced
    
[h264 @ 00000000004cf040] decode_slice_header error
    
[h264 @ 00000000004cf040] no frame!
    
[mpegts @ 00000000004ca9a0] start time for stream 4 is not set in estimate_timings_from_pts
    
[mpegts @ 00000000004ca9a0] start time for stream 7 is not set in estimate_timings_from_pts
    
[mpegts @ 00000000004ca9a0] PES packet size mismatch
    
    Last message repeated 3 times
    
[mpegts @ 00000000004ca9a0] Could not find codec parameters for stream 6 (Unknown: none ([5][0][0][0] / 0x0005)): unknown codec
    
Consider increasing the value for the 'analyzeduration' and 'probesize' options
    
Input #0, mpegts, from 'TV(152420)_001.TSV':
    
  Duration: 01:02:17.92, start: 6188.060000, bitrate: 5877 kb/s
    
  Program 1
    
    Metadata:
    
      service_name    : TV1
    
      service_provider: xxx
    
    Stream #0:0[0x66]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 50 tbr, 90k tbn, 50 tbc
    
    Stream #0:1[0x67](pol): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 160 kb/s
    
    Stream #0:2[0x69](pol): Subtitle: dvb_teletext ([6][0][0][0] / x0006)
    
    Stream #0:3[0x68](qaa): Audio: eac3 (EAC3 / 0x33434145), 48000 Hz, 5.1(side), fltp, 256 kb/s
    
    Stream #0:4[0x6a](pol): Subtitle: dvb_subtitle ([6][0][0][0] / x0006)
    
    Stream #0:5[0x6c](aux): Audio: eac3 (EAC3 / 0x33434145), 48000 Hz, stereo, fltp, 96 kb/s (visual impaired)
    
    Stream #0:6[0x6b]: Unknown: none ([5][0][0][0] / 0x0005)
    
    Stream #0:7[0x6d](eng): Subtitle: dvb_subtitle ([6][0][0][0] / x0006)
    
  Program 2
    
    Metadata:
    
      service_name    : TV2
    
      service_provider: xxx
    
  Program 3
    
    Metadata:
    
      service_name    : TV3
    
      service_provider: xxx

  • very low latency streaminig with ffmpeg using a webcam

    22 mars 2017, par userDtrm

    I’m trying to configure ffmpeg to do a real-time video streaming using a webcam. The ffmpeg encoder command I use is as follows.

    ffmpeg -f v4l2 -input_format yuyv422 -s 640x480 -i /dev/video0 -c:v libx264 -profile:v baseline -trellis 0 -subq 1 -level 32 -preset superfast -tune zerolatency -me_method epzs -crf 30 -threads 0 -bufsize 1 -refs 4 -coder 0 -b_strategy 0 -bf 0 -sc_threshold 0 -x264-params vbv-maxrate=2000:slice-max-size=1500:keyint=30:min-keyint=10: -pix_fmt yuv420p -an -f mpegts udp://192.168.1.8:5001

    The ffplay command used to display the video feed is,

    ffplay -analyzeduration 1 -fflags -nobuffer -i udp://192.168.1.8:5001

    However, I’m experiencing a latency of 0.5 - 1.0s latency in the video stream. Is there a way to reduce this to a number less than 100ms. Also, when I replace the v4l2 camera capture with a screen capture using x11grab, the stream is almost real-time and I experience no noticeable delays. Moreover, changing the encoder from x264 to mpeg2 had no effect on the latency. In addition, the statistics from the ffmpeg shows that the encoder is performing at a 30fps rate, which I believe indicates that the encoding is real-time. This leaves me with only one reason for the experienced delay.

    • Is there a significant delay in buffers when using v4l2 during video capturing in a webcam ?
    • I don’t think the transmission delay is in effect in this case as I see no latencies when screen capture is used under the same conditions.
    • Can this latency be further reduced ?. Can someone think of a different encoder configuration to be used instead of the one that I’ve been using ?.

    Any suggestions or assistance is highly appreciated.

    Thank You.

  • GOP size for realtime video stream

    7 janvier 2017, par MadMass

    I’m working on a kind of rich remote desktop system, with a video stream of the desktop encoded using avcodec/x264. I have to set manually the GOP size for the stream, and so far I was using a size of fps/2.
    But I’ve just read the following on Wikipedia :

    This structure [Group Of Picture@ suggests a problem because the fourth frame (a P-frame) is needed in order to predict the second and the third (B-frames). So we need to transmit the P-frame before the B-frames and it will delay the transmission (it will be necessary to keep the P-frame).

    It means I’m creating a lot of latency since the client needs to receive at least half of the GOP to output the first frame following the I frame. What is the best strategy for the GOP size if I want the smallest latency possible ? A gop of 1 picture ?

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