Sur d’autres sites (4520)

• How to use ffmpeg in JavaScript to decode H.264 frames into RGB frames

  17 juin 2020, par noel

  I'm trying to compile ffmpeg into javascript so that I can decode H.264 video streams using node. The streams are H.264 frames packed into RTP NALUs so any solution has to be able to accept H.264 frames rather than a whole file name. These frames can't be in a container like MP4 or AVI because then the demuxer needs to needs the timestamp of every frame before demuxing can occur, but I'm dealing with a real time stream, no containers.

  



  Streaming H.264 over RTP

  



  Below is the basic code I'm using to listen on a udp socket. Inside the 'message' callback the data packet is an RTP datagram. The data portion of the data gram is an H.264 frame (P-frames and I-frames).

  



  var PORT = 33333;
var HOST = '127.0.0.1';

var dgram = require('dgram');
var server = dgram.createSocket('udp4');

server.on('listening', function () {
    var address = server.address();
    console.log('UDP Server listening on ' + address.address + ":" + address.port);
});

server.on('message', function (message, remote) {
    console.log(remote.address + ':' + remote.port +' - ' + message);
    frame = parse_rtp(message);

    rgb_frame = some_library.decode_h264(frame); // This is what I need.

});

server.bind(PORT, HOST);  


  



  I found the Broadway.js library, but I couldn't get it working and it doesn't handle P-frames which I need. I also found ffmpeg.js, but could get that to work and it needs a whole file not a stream. Likewise, fluent-ffmpeg doesn't appear to support file streams ; all of the examples show a filename being passed to the constructor. So I decided to write my own API.

  



  My current solution attempt

  



  I have been able to compile ffmpeg into one big js file, but I can't use it like that. I want to write an API around ffmpeg and then expose those functions to JS. So it seems to me like I need to do the following :

  



  

  1. Compile ffmpeg components (avcodec, avutil, etc.) into llvm bitcode.

  


  2. Write a C wrapper that exposes the decoding functionality and uses EMSCRIPTEN_KEEPALIVE.

  


  3. Use emcc to compile the wrapper and link it to the bitcode created in step 1.

  


  



  I found WASM+ffmpeg, but it's in Chinese and some of the steps aren't clear. In particular there is this step :

  



  emcc web.c process.c ../lib/libavformat.bc ../lib/libavcodec.bc ../lib/libswscale.bc ../lib/libswresample.bc ../lib/libavutil.bc \


  



   :( Where I think I'm stuck

  



  I don't understand how all the ffmpeg components get compiled into separate *.bc files. I followed the emmake commands in that article and I end up with one big .bc file.

  



  2 questions

  



  1. Does anyone know the steps to compile ffmpeg using emscripten so that I can expose some API to javascript ?
  
 2. Is there a better way (with decent documentation/examples) to decode h264 video streams using node ?

  


• Anomalie #4747 (Nouveau) : Notices PHP sur ?exec=auteur

  27 avril 2021

  J’ai ces notices (sur 3.3 dev)

  <span class="CodeRay"><span class="label">Warning</span>: <span class="constant">Undefined</span> <span class="predefined">array</span> <span class="predefined">key</span> <span class="string"><span class="delimiter">"</span><span class="content">nom</span><span class="delimiter">"</span></span> inecrire/<span class="keyword">public</span>/jointures.php on line <span class="integer">162</span>
  <span class="constant">Warning</span>: <span class="constant">Undefined</span> <span class="predefined">array</span> <span class="predefined">key</span> <span class="string"><span class="delimiter">"</span><span class="content">gram</span><span class="delimiter">"</span></span> in ecrire/<span class="keyword">public</span>/jointures.php on line <span class="integer">162</span>
  </span>
  Télécharger

  Ceci provient de objet_test_si_publie() dans objet_modifier().
  Celui ci

  - crée une Boucle sans déclarer de ->desc,
  - appele instituer_boucle()
  - qui appelle fabrique_jointures()
  - qui teste $cpt = &$num[$boucle->descr['nom']][$boucle->descr['gram']][$boucle->id_boucle];

• Displaying 25 inputs into a 5x5 grid using -ffmpeg- with the correct layout code

  1er septembre 2021, par Clive Nicholas

  I'm now looking to expand the 4x4 code very helpfully provided by @llogan yesterday into one taking 25 different and equally-scaled audio and video inputs to make a 5x5 grid (at which point, I'll stop) :

  


  ffmpeg -i a.mp4 -i b.mp4 -i c.mp4 -i d.mp4 -i e.mp4 -i f.mp4 -i g.mp4 -i h.mp4 -i i.mp4 -i j.mp4 -i k.mp4 -i l.mp4 -i m.mp4 -i n.mp4 -i o.mp4 -i p.mp4 -i q.mp4 -i r.mp4 -i s.mp4 -i t.mp4 -i u.mp4 -i v.mp4 -i w.mp4 -i x.mp4 -i y.mp4 \
 -filter_complex \
    "[0:v]scale=iw/5:-1[v0];[1:v]scale=iw/5:-1[v1];[2:v]scale=iw/5:-1[v2]; \ 
     [3:v]scale=iw/5:-1[v3];[4:v]scale=iw/5:-1[v4];[5:v]scale=iw/5:-1[v5]; \ 
     [6:v]scale=iw/5:-1[v6];[7:v]scale=iw/5:-1[v7];[8:v]scale=iw/5:-1[v8]; \ 
     [9:v]scale=iw/5:-1[v9];[10:v]scale=iw/5:-1[v10];[11:v]scale=iw/5:-1[v11]; \
     [12:v]scale=iw/5:-1[v12];[13:v]scale=iw/5:-1[v13];[14:v]scale=iw/5:-1[v14]; \
     [15:v]scale=iw/5:-1[v15];[16:v]scale=iw/5:-1[v16];[17:v]scale=iw/5:-1[v17]; \ 
     [18:v]scale=iw/5:-1[v18];[19:v]scale=iw/5:-1[v19];[20:v]scale=iw/5:-1[v20]; \
     [21:v]scale=iw/5:-1[v21];[22:v]scale=iw/5:-1[v22];[23:v]scale=iw/5:-1[v23]; \ 
     [24:v]scale=iw/5:-1[v24]; \
     [v0][v1][v2][v3][v4][v5][v6][v7][v8][v9][v10][v11][v12][v13][v14][v15][v16][v17][v18][v19][v20][v21][v22][v23][v24]xstack=inputs=25:layout=0_0|0_h0|0_h0+h1|0_h0+h1+h2|0_h0+h1+h2+h3|w0_0|w0_h0|w0_h0+h1|w0_h0+h1+h2|w0_h0+h1+h2+h3|w0+w4_0|w0+w4_h0|w0+w4_h0+h1|w0+w4_h0+h1+h2|w0+w4_h0+h1+h2+h3|w0+w4+w8_0|w0+w4+w8_h0|w0+w4+w8_h0+h1|w0+w4+w8_h0+h1+h2|w0+w4+w8_h0+h1+h2+h3|w0+w4+w8+w12_0|w0+w4+w8+w12_h0|w0+w4+w8+w12_h0+h1|w0+w4+w8+w12_h0+h1+h2|w0+w4+w8+w12_h0+h1+h2+h3; \
     [0:a][1:a][2:a][3:a][4:a][5:a][6:a][7:a][8:a][9:a][10:a][11:a][12:a][13:a][14:a][15:a][16:a][17:a][18:a][19:a][20:a][21:a][22:a][23:a][24:a]amix=inputs=25" \
output.mp4


  


  Unfortunately, this produces errors :

  


  ffmpeg version 4.3.2-0+deb11u1ubuntu1 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 10 (Ubuntu 10.2.1-20ubuntu1)
  configuration: --prefix=/usr --extra-version=0+deb11u1ubuntu1 --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-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --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-librabbitmq --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --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-pocketsphinx --enable-libmfx --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=0+deb11u1ubuntu1 --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-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --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-librabbitmq --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --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-pocketsphinx --enable-libmfx --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. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'abc.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:08.00, start: 0.000000, bitrate: 248 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 41 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 193 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'ang.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:10.00, start: 0.000000, bitrate: 480 kb/s
    Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 271 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #2, mov,mp4,m4a,3gp,3g2,mj2, from 'ard.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:09.00, start: 0.000000, bitrate: 256 kb/s
    Stream #2:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 49 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #2:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 193 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #3, mov,mp4,m4a,3gp,3g2,mj2, from 'atv.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:17.00, start: 0.000000, bitrate: 259 kb/s
    Stream #3:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 53 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #3:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 193 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #4, mov,mp4,m4a,3gp,3g2,mj2, from 'bor.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:09.00, start: 0.000000, bitrate: 255 kb/s
    Stream #4:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 48 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #4:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #5, mov,mp4,m4a,3gp,3g2,mj2, from 'cen.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:07.00, start: 0.000000, bitrate: 461 kb/s
    Stream #5:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 250 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #5:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 196 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #6, mov,mp4,m4a,3gp,3g2,mj2, from 'cha.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:05.00, start: 0.000000, bitrate: 267 kb/s
    Stream #6:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 59 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #6:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #7, mov,mp4,m4a,3gp,3g2,mj2, from 'grad.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:05.01, start: 0.000000, bitrate: 246 kb/s
    Stream #7:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 39 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #7:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #8, mov,mp4,m4a,3gp,3g2,mj2, from 'gram.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:09.00, start: 0.000000, bitrate: 294 kb/s
    Stream #8:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 86 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #8:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 195 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #9, mov,mp4,m4a,3gp,3g2,mj2, from 'htv.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:12.01, start: 0.000000, bitrate: 238 kb/s
    Stream #9:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 29 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #9:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 196 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #10, mov,mp4,m4a,3gp,3g2,mj2, from 'its1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:07.00, start: 0.000000, bitrate: 238 kb/s
    Stream #10:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 31 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #10:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #11, mov,mp4,m4a,3gp,3g2,mj2, from 'its2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:08.00, start: 0.000000, bitrate: 241 kb/s
    Stream #11:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 34 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #11:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #12, mov,mp4,m4a,3gp,3g2,mj2, from 'lwt.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:10.00, start: 0.000000, bitrate: 239 kb/s
    Stream #12:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 30 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #12:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 195 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #13, mov,mp4,m4a,3gp,3g2,mj2, from 'sou.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:08.00, start: 0.000000, bitrate: 247 kb/s
    Stream #13:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 39 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #13:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #14, mov,mp4,m4a,3gp,3g2,mj2, from 'stv.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:09.00, start: 0.000000, bitrate: 257 kb/s
    Stream #14:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 51 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #14:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #15, mov,mp4,m4a,3gp,3g2,mj2, from 'tha.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:06.00, start: 0.000000, bitrate: 454 kb/s
    Stream #15:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 245 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #15:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #16, mov,mp4,m4a,3gp,3g2,mj2, from 'tlc.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:09.00, start: 0.000000, bitrate: 275 kb/s
    Stream #16:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 67 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #16:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #17, mov,mp4,m4a,3gp,3g2,mj2, from 'tsw.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:11.00, start: 0.000000, bitrate: 457 kb/s
    Stream #17:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 251 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #17:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #18, mov,mp4,m4a,3gp,3g2,mj2, from 'ttt.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:10.01, start: 0.000000, bitrate: 258 kb/s
    Stream #18:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 51 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #18:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 193 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #19, mov,mp4,m4a,3gp,3g2,mj2, from 'tvam.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.82.100
  Duration: 00:00:11.31, start: 0.000000, bitrate: 383 kb/s
    Stream #19:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 352x288 [SAR 178:163 DAR 1958:1467], 251 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #19:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #20, mov,mp4,m4a,3gp,3g2,mj2, from 'tvs.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:10.01, start: 0.000000, bitrate: 252 kb/s
    Stream #20:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 44 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #20:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #21, mov,mp4,m4a,3gp,3g2,mj2, from 'tww.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:09.00, start: 0.000000, bitrate: 277 kb/s
    Stream #21:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 69 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #21:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #22, mov,mp4,m4a,3gp,3g2,mj2, from 'utv.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:08.00, start: 0.000000, bitrate: 443 kb/s
    Stream #22:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 234 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #22:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #23, mov,mp4,m4a,3gp,3g2,mj2, from 'wtv.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:08.00, start: 0.000000, bitrate: 431 kb/s
    Stream #23:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 224 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #23:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 194 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #24, mov,mp4,m4a,3gp,3g2,mj2, from 'ytv.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:08.00, start: 0.000000, bitrate: 332 kb/s
    Stream #24:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 123 kb/s, 60 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #24:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 195 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
[AVFilterGraph @ 0x55ad3b4d4a00] No such filter: ' '
Error initializing complex filters.
Invalid argument


  


  The layout code has now become extremely complex, but I've carefully followed the 4x4 example as given in the manual here and I don't think I'm doing much wrong. Breaking down and reordering the layout code I used above looks like this :

  


  input1(0, 0)          | input6 (w0, 0)           | input11(w0+w4, 0)          | input16(w0+w4+w8, 0)          | input21(w0+w4+w8+w12, 0)
input2(0, h0)         | input7 (w0, h0)          | input12(w0+w4, h0)         | input17(w0+w4+w8, h0)         | input22(w0+w4+w8+w12, h0)
input3(0, h0+h1)      | input8 (w0, h0+h1)       | input13(w0+w4, h0+h1)      | input18(w0+w4+w8, h0+h1)      | input23(w0+w4+w8+w12, h0+h1)
input4(0, h0+h1+h2)   | input9 (w0, h0+h1+h2)    | input14(w0+w4, h0+h1+h2)   | input19(w0+w4+w8, h0+h1+h2)   | input24(w0+w4+w8+w12, h0+h1+h2)
input5(0, h0+h1+h2+h3)| input10(w0, h0+h1+h2+h3) | input15(w0+w4, h0+h1+h2+h3)| input20(w0+w4+w8, h0+h1+h2+h3)| input25(w0+w4+w8+w12, h0+h1+h2+h3)


  


  To my mind, w12 and h3 would logically be the next set of width and height parameters to add on in order to make the grid expansion from 4x4 to 5x5 work. Is that what's causing the code to choke ? If it's not this, it's not obvious to me what it might be, as I've checked the whole code as thoroughly as possible.

  


  Once again, I'll be very grateful for your assistance.

  


  Thanks very much, Clive