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  • Menus personnalisés

    14 novembre 2010, par

    MediaSPIP utilise le plugin Menus pour gérer plusieurs menus configurables pour la navigation.
    Cela permet de laisser aux administrateurs de canaux la possibilité de configurer finement ces menus.
    Menus créés à l’initialisation du site
    Par défaut trois menus sont créés automatiquement à l’initialisation du site : Le menu principal ; Identifiant : barrenav ; Ce menu s’insère en général en haut de la page après le bloc d’entête, son identifiant le rend compatible avec les squelettes basés sur Zpip ; (...)

  • Selection of projects using MediaSPIP

    2 mai 2011, par

    The examples below are representative elements of MediaSPIP specific uses for specific projects.
    MediaSPIP farm @ Infini
    The non profit organizationInfini develops hospitality activities, internet access point, training, realizing innovative projects in the field of information and communication technologies and Communication, and hosting of websites. It plays a unique and prominent role in the Brest (France) area, at the national level, among the half-dozen such association. Its members (...)

  • Mise à disposition des fichiers

    14 avril 2011, par

    Par défaut, lors de son initialisation, MediaSPIP ne permet pas aux visiteurs de télécharger les fichiers qu’ils soient originaux ou le résultat de leur transformation ou encodage. Il permet uniquement de les visualiser.
    Cependant, il est possible et facile d’autoriser les visiteurs à avoir accès à ces documents et ce sous différentes formes.
    Tout cela se passe dans la page de configuration du squelette. Il vous faut aller dans l’espace d’administration du canal, et choisir dans la navigation (...)

Sur d’autres sites (3510)

  • Why does ffmpeg hang when I try to use my webcam's raw stream ?

    25 septembre 2021, par Sam Middleton

    I'm trying to use ffmpeg to record videos from a webcam.

    


    When I run ffmpeg -f v4l2 -list_formats all -i /dev/video0 I get the following output :

    


    ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  WARNING: library configuration mismatch
  avcodec     configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared --enable-version3 --disable-doc --disable-programs --enable-libaribb24 --enable-liblensfun --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libtesseract --enable-libvo_amrwbenc
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
[video4linux2,v4l2 @ 0x55f3fbd816c0] Compressed:       mjpeg :          Motion-JPEG : 1920x1080
[video4linux2,v4l2 @ 0x55f3fbd816c0] Raw       :     yuyv422 :           YUYV 4:2:2 : 1920x1080
/dev/video0: Immediate exit requested


    


    I can record by using the command ffmpeg -f v4l2 -input_format mjpeg -i /dev/video0 -t 30 output.mp4

    


    But if I specify -input_format yuyv442 instead, ffmpeg outputs the following and hangs :

    


    ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  WARNING: library configuration mismatch
  avcodec     configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared --enable-version3 --disable-doc --disable-programs --enable-libaribb24 --enable-liblensfun --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libtesseract --enable-libvo_amrwbenc
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100


    


    If I press Ctl-C, it then prints the following :

    


    Input #0, video4linux2,v4l2, from '/dev/video0':
  Duration: N/A, bitrate: 995328 kb/s
    Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 1920x1080, 995328 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
Press [q] to stop, [?] for help
Finishing stream 0:0 without any data written to it.
[libx264 @ 0x55eda0567640] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x55eda0567640] profile High 4:2:2, level 4.0, 4:2:2 8-bit
[libx264 @ 0x55eda0567640] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=24 lookahead_threads=4 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'output.mp4':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv422p, 1920x1080, q=-1--1, 30 fps, 15360 tbn, 30 tbc
    Metadata:
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame=    0 fps=0.0 q=0.0 Lsize=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Exiting normally, received signal 2.


    


    Also, if output.mp4 already exists, I get the Overwrite ? [y/N] prompt after I Ctl-C.

    


    Does anyone know what is causing this and how I can fix it ?

    


  • FFMpeg produces low quality target file with just 1 second length on Ubuntu 20.04

    16 juillet 2021, par Matt

    I'm using FFMpeg locally on a Mac (actually using PHP-FFMpeg) and it's working perfectly. I'm running the same code on an Ubuntu server and whatever I try the output file is a tiny, low quality video with just 1 second length (the original is about 15 seconds).

    


    I installed it on the server with

    


    sudo apt update
sudo apt install ffmpeg


    


    and then restarted the server. To test now I'm running

    


    ffmpeg -i source.mp4 target.mp4


    


    from the terminal and getting this output

    


    ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'source.mp4':
  Metadata:
    major_brand     : iso5
    minor_version   : 1
    compatible_brands: isomiso5hlsf
    creation_time   : 2021-07-16T05:37:58.000000Z
  Duration: 00:00:00.66, start: 0.000000, bitrate: 74037 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 640x480 [SAR 1:1 DAR 4:3], 83522 kb/s, 30.20 fps, 600 tbr, 600 tbn, 1200 tbc (default)
    Metadata:
      creation_time   : 2021-07-16T05:37:58.000000Z
      handler_name    : Core Media Video
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 1774 kb/s (default)
    Metadata:
      creation_time   : 2021-07-16T05:37:58.000000Z
      handler_name    : Core Media Audio
File 'target.mp4' already exists. Overwrite ? [y/N] y
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x55db778748c0] using SAR=1/1
[libx264 @ 0x55db778748c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x55db778748c0] profile High, level 3.0
[libx264 @ 0x55db778748c0] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
frame=    8 fps=0.0 q=0.0 size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbOutput #0, mp4, to 'target.mp4':
  Metadata:
    major_brand     : iso5
    minor_version   : 1
    compatible_brands: isomiso5hlsf
    encoder         : Lavf58.29.100
    Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 640x480 [SAR 1:1 DAR 4:3], q=-1--1, 30.20 fps, 28k tbn, 30.20 tbc (default)
    Metadata:
      creation_time   : 2021-07-16T05:37:58.000000Z
      handler_name    : Core Media Video
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 69 kb/s (default)
    Metadata:
      creation_time   : 2021-07-16T05:37:58.000000Z
      handler_name    : Core Media Audio
      encoder         : Lavc58.54.100 aac
frame=   15 fps= 14 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A dup=3 droframe=   18 fps= 11 q=0.0 size=       0kB time=00:00:00.46 bitrate=   0.8kbits/sframe=   18 fps=7.9 q=0.0 size=       0kB time=00:00:00.46 bitrate=   0.8kbits/sframe=   18 fps=6.4 q=0.0 size=       0kB time=00:00:00.46 bitrate=   0.8kbits/sframe=   19 fps=5.8 q=0.0 size=       0kB time=00:00:00.46 bitrate=   0.8kbits/sframe=   19 fps=5.0 q=0.0 size=       0kB time=00:00:00.46 bitrate=   0.8kbits/sframe=   20 fps=4.6 q=0.0 size=       0kB time=00:00:00.46 bitrate=   0.8kbits/s[aac @ 0x55db778a2f00] Queue input is backward in time
[mp4 @ 0x55db77876100] Non-monotonous DTS in output stream 0:1; previous: 23552, current: 20480; changing to 23553. This may result in incorrect timestamps in the output file.
[mp4 @ 0x55db77876100] Non-monotonous DTS in output stream 0:1; previous: 23553, current: 21504; changing to 23554. This may result in incorrect timestamps in the output file.
[mp4 @ 0x55db77876100] Non-monotonous DTS in output stream 0:1; previous: 23554, current: 22528; changing to 23555. This may result in incorrect timestamps in the output file.
[mp4 @ 0x55db77876100] Non-monotonous DTS in output stream 0:1; previous: 23555, current: 23552; changing to 23556. This may result in incorrect timestamps in the output file.
frame=   20 fps=3.3 q=-1.0 Lsize=      77kB time=00:00:00.56 bitrate=1122.7kbits/s dup=3 drop=3 speed=0.0936x    
video:69kB audio:6kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.688508%
[libx264 @ 0x55db778748c0] frame I:1     Avg QP:22.13  size: 14863
[libx264 @ 0x55db778748c0] frame P:5     Avg QP:25.37  size:  6279
[libx264 @ 0x55db778748c0] frame B:14    Avg QP:26.80  size:  1720
[libx264 @ 0x55db778748c0] consecutive B-frames:  5.0%  0.0% 15.0% 80.0%
[libx264 @ 0x55db778748c0] mb I  I16..4: 15.9% 65.9% 18.2%
[libx264 @ 0x55db778748c0] mb P  I16..4: 10.6% 11.7%  1.3%  P16..4: 52.4% 11.2%  5.5%  0.0%  0.0%    skip: 7.4%
[libx264 @ 0x55db778748c0] mb B  I16..4:  1.0%  1.3%  0.4%  B16..8: 35.8%  3.0%  0.5%  direct: 2.4%  skip:55.6%  L0:41.2% L1:55.5% BI: 3.3%
[libx264 @ 0x55db778748c0] 8x8 transform intra:56.1% inter:82.3%
[libx264 @ 0x55db778748c0] coded y,uvDC,uvAC intra: 54.1% 75.0% 21.1% inter: 14.6% 25.2% 0.1%
[libx264 @ 0x55db778748c0] i16 v,h,dc,p:  9% 19%  3% 70%
[libx264 @ 0x55db778748c0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 18% 24%  5%  6%  9%  6%  6%  6%
[libx264 @ 0x55db778748c0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 30% 20% 16%  6%  7%  7%  6%  5%  3%
[libx264 @ 0x55db778748c0] i8c dc,h,v,p: 48% 25% 22%  5%
[libx264 @ 0x55db778748c0] Weighted P-Frames: Y:40.0% UV:40.0%
[libx264 @ 0x55db778748c0] ref P L0: 62.4% 17.4% 14.3%  5.7%  0.1%
[libx264 @ 0x55db778748c0] ref B L0: 87.6% 10.7%  1.7%
[libx264 @ 0x55db778748c0] ref B L1: 95.0%  5.0%
[libx264 @ 0x55db778748c0] kb/s:849.86
[aac @ 0x55db778a2f00] Qavg: 4594.708


    


    Here's what the files look like

    


    enter image description here

    


    Any ideas what could be wrong ?
Thanks for your help !

    


  • A pragmatic strategy to merge multiple video files

    19 juin 2021, par saurav

    I currently am working on recording a multiparty video conference which supports up to 6 participants. I am recording the conference using a media server and storing audio/video streams individually for every participant.

    


    Next, I need to merge those individual recordings into a single video file and upload it to a cloud storage like aws s3. For this I am considering 2 options, either Gstreamer or FFMPEG. I am leaning towards FFMPEG as I have used FFMPEG previously. I currently am playing with FFMPEG things like the hstack and vstack filters etc.

    


    Here is the FFMPEG command I recently used to join 2 webm videos of 2 mins 40sec and 1min 40sec to create a mp4 video file for upload. Both the videos are 1280x720 in this case but I have included the scale part because in real life scenario different participants joining with different cameras produces video files of different resolution which is a problem for the hstack/vstack filter. Therefore, to make the video resolutions of all participant consistent, I have included the scale property.

    


    ffmpeg -i 1.webm -i 2.webm -filter_complex "[0:v]scale=1280:720,setsar=1[l];[1:v]scale=1280:720,setsar=1[r];[l][r]hstack;[0][1]amix" output-1280x720.mp4


    


    Currently I am facing 2 issues with this command.

    


      

    1. The output mp4 file is very big, in this case 140Mb (approx) for a less than 3 minutes video.

      


    2. 


    3. How do I add delay to any video before starting to merge ?
      
Currently the videos are going out of sync if all the participants don't join at the same time which is highly unlikely to happen in a real world scenario.

      


    4. 


    


    Any pointer in the right direction will be highly appreciated.

    


    Here is a log sample from FFmpeg (or see the full log link) :

    


    ffmpeg version 4.2.4-1ubuntu0.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, matroska,webm, from '3.webm':
  Metadata:
    title           : FFmpeg
    ENCODER         : Lavf58.29.100
  Duration: 00:01:39.63, start: 0.000000, bitrate: 707 kb/s
    Stream #0:0: Video: vp8, yuv420p(tv, bt470bg/unknown/unknown, progressive), 1280x720, SAR 1:1 DAR 16:9, 1k tbr, 1k tbn, 1k tbc (default)
    Metadata:
      DURATION        : 00:01:39.618000000
    Stream #0:1: Audio: opus, 48000 Hz, stereo, fltp (default)
    Metadata:
      DURATION        : 00:01:39.629000000
Input #1, matroska,webm, from '4.webm':
  Metadata:
    title           : FFmpeg
    ENCODER         : Lavf58.29.100
  Duration: 00:02:39.07, start: 0.000000, bitrate: 708 kb/s
    Stream #1:0: Video: vp8, yuv420p(tv, bt470bg/unknown/unknown, progressive), 1280x720, SAR 1:1 DAR 16:9, 1k tbr, 1k tbn, 1k tbc (default)
    Metadata:
      DURATION        : 00:02:39.050000000
    Stream #1:1: Audio: opus, 48000 Hz, stereo, fltp (default)
    Metadata:
      DURATION        : 00:02:39.068000000
Stream mapping:
  Stream #0:0 (vp8) -> scale
  Stream #0:1 (opus) -> amix:input0
  Stream #1:0 (vp8) -> scale
  Stream #1:1 (opus) -> amix:input1
  hstack -> Stream #0:0 (libx264)
  amix -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[libx264 @ 0x562b4842a500] using SAR=1/1
[libx264 @ 0x562b4842a500] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x562b4842a500] profile High, level 6.1
[libx264 @ 0x562b4842a500] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=18 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'output-new.mp4':
  Metadata:
    title           : FFmpeg
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 2560x720 [SAR 1:1 DAR 32:9], q=-1--1, 1k fps, 16k tbn, 1k tbc (default)
    Metadata:
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      encoder         : Lavc58.54.100 aac

frame=  129 fps=0.0 q=33.0 size=       0kB time=00:00:00.23 bitrate=   1.6kbits/s dup=123 drop=0 speed=0.44x    
frame=  257 fps=228 q=33.0 size=       0kB time=00:00:00.51 bitrate=   0.8kbits/s dup=243 drop=0 speed=0.455x    
frame=  379 fps=224 q=33.0 size=     256kB time=00:00:00.73 bitrate=2855.1kbits/s dup=358 drop=0 speed=0.434x    
frame=  497 fps=222 q=33.0 size=     256kB time=00:00:00.86 bitrate=2431.5kbits/s dup=469 drop=0 speed=0.386x    
 
...
More than 1000 frames duplicated
...
  
frame=158751 fps=196 q=33.0 size=  134656kB time=00:02:39.00 bitrate=6937.4kbits/s dup=151385 drop=0 speed=0.196x    
frame=158851 fps=196 q=33.0 size=  134912kB time=00:02:39.00 bitrate=6950.6kbits/s dup=151482 drop=0 speed=0.196x    
frame=158983 fps=196 q=33.0 size=  134912kB time=00:02:39.00 bitrate=6950.6kbits/s dup=151610 drop=0 speed=0.196x    
frame=159081 fps=196 q=-1.0 Lsize=  137197kB time=00:02:39.07 bitrate=7065.2kbits/s dup=151706 drop=0 speed=0.196x    

video:132693kB audio:2494kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.486001%

[libx264 @ 0x562b4842a500] frame I:637   Avg QP:17.73  size:123895
[libx264 @ 0x562b4842a500] frame P:40088 Avg QP:19.73  size:  1134
[libx264 @ 0x562b4842a500] frame B:118356 Avg QP:27.54  size:    97
[libx264 @ 0x562b4842a500] consecutive B-frames:  0.8%  0.0%  0.0% 99.2%
[libx264 @ 0x562b4842a500] mb I  I16..4: 11.1% 67.3% 21.6%
[libx264 @ 0x562b4842a500] mb P  I16..4:  0.1%  0.1%  0.0%  P16..4:  2.6%  0.4%  0.3%  0.0%  0.0%    skip:96.5%
[libx264 @ 0x562b4842a500] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.7%  0.0%  0.0%  direct: 0.0%  skip:99.3%  L0:38.7% L1:61.3% BI: 0.0%
[libx264 @ 0x562b4842a500] 8x8 transform intra:66.8% inter:71.4%
[libx264 @ 0x562b4842a500] coded y,uvDC,uvAC intra: 81.8% 89.5% 72.3% inter: 0.2% 0.4% 0.0%
[libx264 @ 0x562b4842a500] i16 v,h,dc,p: 25% 21% 17% 37%
[libx264 @ 0x562b4842a500] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 22% 12%  4%  5%  6%  6%  6%  6%
[libx264 @ 0x562b4842a500] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 42% 24%  6%  4%  5%  5%  6%  4%  4%
[libx264 @ 0x562b4842a500] i8c dc,h,v,p: 42% 24% 26%  9%
[libx264 @ 0x562b4842a500] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x562b4842a500] ref P L0: 82.4% 11.5%  5.3%  0.8%
[libx264 @ 0x562b4842a500] ref B L0: 83.0% 16.9%  0.1%
[libx264 @ 0x562b4842a500] ref B L1: 94.9%  5.1%
[libx264 @ 0x562b4842a500] kb/s:6833.11
[aac @ 0x562b4842b540] Qavg: 239.393