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Organiser par catégorie
17 mai 2013, parDans MédiaSPIP, une rubrique a 2 noms : catégorie et rubrique.
Les différents documents stockés dans MédiaSPIP peuvent être rangés dans différentes catégories. On peut créer une catégorie en cliquant sur "publier une catégorie" dans le menu publier en haut à droite ( après authentification ). Une catégorie peut être rangée dans une autre catégorie aussi ce qui fait qu’on peut construire une arborescence de catégories.
Lors de la publication prochaine d’un document, la nouvelle catégorie créée sera proposée (...) -
Les thèmes de MediaSpip
4 juin 20133 thèmes sont proposés à l’origine par MédiaSPIP. L’utilisateur MédiaSPIP peut rajouter des thèmes selon ses besoins.
Thèmes MediaSPIP
3 thèmes ont été développés au départ pour MediaSPIP : * SPIPeo : thème par défaut de MédiaSPIP. Il met en avant la présentation du site et les documents média les plus récents ( le type de tri peut être modifié - titre, popularité, date) . * Arscenic : il s’agit du thème utilisé sur le site officiel du projet, constitué notamment d’un bandeau rouge en début de page. La structure (...) -
Dépôt de média et thèmes par FTP
31 mai 2013, parL’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.
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Ffmpeg rounds seconds instead of using the milliseconds part
10 mai 2021, par NourElDineAI tried to cut a video using the following command :


ffmpeg -i input.mp4 -ss 00:00:00 -to 00:00:06.600 output.mp4



When I run the command ffmpeg rounds up and the output video is 7 seconds instead of 6.6 seconds.
I would like to know if there is a way to cut the video precisely where I tell it to.


Here is the log file content :


ffmpeg version 4.3.1-2021-01-01-full_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers
 built with gcc 10.2.0 (Rev5, Built by MSYS2 project)
 configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-libsnappy --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
 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
 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 'out2.mp4':
 Metadata:
 major_brand : isom
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 encoder : Lavf58.45.100
 Duration: 00:00:10.52, start: 0.000000, bitrate: 1070 kb/s
 Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 960x720 [SAR 1:1 DAR 4:3], 935 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
 Metadata:
 handler_name : Telestream Inc. Dib Library - ReleaseVantage 2014.59.138974
 Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 126 kb/s (default)
 Metadata:
 handler_name : Telestream Inc. Dib Library - ReleaseVantage 2014.59.138974
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 @ 0000015de0911400] using SAR=1/1
[libx264 @ 0000015de0911400] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0000015de0911400] profile High, level 3.1, 4:2:0, 8-bit
[libx264 @ 0000015de0911400] 264 - core 161 r3027 4121277 - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - 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=12 lookahead_threads=2 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 'out3.mp4':
 Metadata:
 major_brand : isom
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 encoder : Lavf58.45.100
 Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 960x720 [SAR 1:1 DAR 4:3], q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc (default)
 Metadata:
 handler_name : Telestream Inc. Dib Library - ReleaseVantage 2014.59.138974
 encoder : Lavc58.91.100 libx264
 Side data:
 cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
 Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
 Metadata:
 handler_name : Telestream Inc. Dib Library - ReleaseVantage 2014.59.138974
 encoder : Lavc58.91.100 aac
frame= 100 fps=0.0 q=29.0 size= 0kB time=00:00:03.56 bitrate= 0.1kbits/s speed=6.78x 
frame= 172 fps=167 q=29.0 size= 256kB time=00:00:05.95 bitrate= 352.4kbits/s speed=5.77x 
frame= 198 fps=126 q=-1.0 Lsize= 818kB time=00:00:06.61 bitrate=1013.6kbits/s speed=4.22x 
video:709kB audio:100kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.054347%
[libx264 @ 0000015de0911400] frame I:1 Avg QP: 3.25 size: 178
[libx264 @ 0000015de0911400] frame P:84 Avg QP:18.55 size: 6826
[libx264 @ 0000015de0911400] frame B:113 Avg QP:20.94 size: 1347
[libx264 @ 0000015de0911400] consecutive B-frames: 1.5% 66.7% 1.5% 30.3%
[libx264 @ 0000015de0911400] mb I I16..4: 100.0% 0.0% 0.0%
[libx264 @ 0000015de0911400] mb P I16..4: 5.8% 6.9% 0.6% P16..4: 40.1% 4.8% 3.4% 0.0% 0.0% skip:38.4%
[libx264 @ 0000015de0911400] mb B I16..4: 0.1% 0.3% 0.0% B16..8: 12.1% 0.8% 0.1% direct: 6.5% skip:80.1% L0:33.9% L1:60.4% BI: 5.7%
[libx264 @ 0000015de0911400] 8x8 transform intra:48.3% inter:70.6%
[libx264 @ 0000015de0911400] coded y,uvDC,uvAC intra: 13.6% 73.4% 33.1% inter: 4.1% 20.1% 0.5%
[libx264 @ 0000015de0911400] i16 v,h,dc,p: 92% 4% 3% 2%
[libx264 @ 0000015de0911400] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 13% 7% 65% 2% 3% 3% 3% 3% 2%
[libx264 @ 0000015de0911400] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 16% 22% 5% 7% 7% 7% 6% 3%
[libx264 @ 0000015de0911400] i8c dc,h,v,p: 54% 20% 23% 4%
[libx264 @ 0000015de0911400] Weighted P-Frames: Y:6.0% UV:6.0%
[libx264 @ 0000015de0911400] ref P L0: 69.2% 5.3% 17.7% 7.7% 0.1%
[libx264 @ 0000015de0911400] ref B L0: 92.8% 6.2% 1.0%
[libx264 @ 0000015de0911400] ref B L1: 99.5% 0.5%
[libx264 @ 0000015de0911400] kb/s:878.78
[aac @ 0000015de0914080] Qavg: 6573.620



The output file is 7 seconds long which means ffmpeg rounded up my 6.60 to 7 and I need it to cut exactly at 00:00:06.60


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ffmpeg overlay fadein/fadeout is not working [duplicate]
22 avril 2021, par user15602767This is my normal overlay filter without any fadein/fadeout


ffmpeg -i .\urban_pop_b4.mp4 -i .\logos\cfe-coffee.png -filter_complex "overlay=700:300:enable=between(t\,3\,6)" output.mp4



When I include the fade-in/fade-out option as in docs I dont get any overlay at all(no error thrown)


ffmpeg -i .\urban_pop_b4.mp4 -i .\logos\cfe-coffee.png -filter_complex "[1:v]fade=t=in:st=5:d=1,fade=t=out:st=10:d=1[over];[0:v][over]overlay=700:300:enable=between(t\,3\,6)" output.mp4



ffmpeg version 2021-04-07-git-c06465a70b-full_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers built with gcc 10.2.0 (Rev6, Built by MSYS2 project) configuration: --enable-gpl
--enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint libavutil 56. 72.100 / 56. 72.100 libavcodec 58.135.100 / 58.135.100 libavformat 58. 77.100 /
58. 77.100 libavdevice 58. 14.100 / 58. 14.100 libavfilter 7.111.100 / 7.111.100 libswscale 5. 10.100 / 5. 10.100 libswresample 3. 10.100 / 3. 10.100 libpostproc 55. 10.100 /
55. 10.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '.\urban_pop.mp4': Metadata:
 major_brand : isom
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 encoder : Lavf58.77.100 Duration: 00:00:21.05, start: 0.000000, bitrate: 413 kb/s Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 832x432, 411 kb/s, 20 fps, 20 tbr, 10240 tbn, 40 tbc (default)
 Metadata:
 handler_name : VideoHandler
 vendor_id : [0][0][0][0] Input #1, png_pipe, from '.\logos\cfe-coffee.png': Duration: N/A, bitrate: N/A Stream #1:0: Video: png, rgba(pc), 256x192, 25 fps, 25 tbr, 25 tbn, 25 tbc Stream mapping: Stream #0:0 (h264) -> overlay:main Stream #1:0 (png) -> fade overlay -> Stream #0:0 (libx264) Press [q] to stop, [?] for help [libx264 @ 00000271483e1240] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 [libx264 @ 00000271483e1240] profile High, level 3.0, 4:2:0, 8-bit [libx264 @ 00000271483e1240] 264
- core 161 r3048 b86ae3c - H.264/MPEG-4 AVC codec - Copyleft 2003-2021 - 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=6 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=20 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:
 major_brand : isom
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 encoder : Lavf58.77.100 Stream #0:0: Video: h264 (avc1 / 0x31637661), yuv420p(progressive), 832x432, q=2-31, 20 fps, 10240 tbn (default)
 Metadata:
 encoder : Lavc58.135.100 libx264
 Side data:
 cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A frame= 421 fps=0.0 q=-1.0 Lsize= 1052kB time=00:00:20.90 bitrate=
412.3kbits/s speed=21.9x video:1046kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.552964% [libx264 @ 00000271483e1240] frame I:2 Avg QP:13.84 size: 19321 [libx264 @ 00000271483e1240] frame P:106 Avg QP:22.42 size: 3482 [libx264 @ 00000271483e1240] frame B:313 Avg QP:28.03 size: 2117 [libx264 @ 00000271483e1240] consecutive B-frames: 0.7% 0.5% 0.0% 98.8% [libx264 @ 00000271483e1240] mb I I16..4: 54.9% 18.3% 26.8% [libx264 @ 00000271483e1240] mb P I16..4: 0.7% 0.4% 1.3% P16..4: 5.6% 
2.8% 1.6% 0.0% 0.0% skip:87.6% [libx264 @ 00000271483e1240] mb B I16..4: 0.1% 0.1% 0.4% B16..8: 5.6% 2.4% 1.2% direct: 0.5% skip:89.8% L0:49.1% L1:44.2% BI: 6.7% [libx264 @ 00000271483e1240] 8x8 transform intra:15.4% inter:6.9% [libx264 @ 00000271483e1240] coded y,uvDC,uvAC intra: 36.1% 8.1% 5.7% inter: 2.6% 0.2% 0.1% [libx264 @ 00000271483e1240] i16 v,h,dc,p: 59% 35% 5% 0% [libx264 @ 00000271483e1240] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 27% 9% 61% 0% 0% 0% 0% 0% 1% [libx264 @ 00000271483e1240] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 19% 30% 3% 3% 3% 3% 6% 4% [libx264 @ 00000271483e1240] i8c dc,h,v,p: 84% 13% 4% 0% [libx264 @ 00000271483e1240] Weighted P-Frames: Y:0.0% UV:0.0% [libx264 @ 00000271483e1240] ref P L0: 59.3% 4.0% 20.8% 15.9% [libx264 @ 00000271483e1240] ref B L0: 70.8% 21.6% 7.6% [libx264 @ 00000271483e1240] ref B L1: 87.6% 12.4% [libx264 @ 00000271483e1240] kb/s:406.82



Already tried out ffmpeg overlay image with fade in and fade out


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Superimposing two videos onto a static image ?
15 décembre 2014, par ArchagonI have two videos that I’d like to combine into a single video, in which both videos would sit on top of a static background image. (Think something like this.) My requirements are that the software I use is free, that it runs on OSX, and that I don’t have to re-encode my videos an excessive number of times. I’d also like to be able to perform this operation from the command line or via script, since I’ll be doing it a lot. (But this isn’t strictly necessary.)
I tried fiddling with ffmpeg for a couple of hours, but it just doesn’t seem very well suited for post-processing. I could potentially hack something together via the overlay feature, but so far I haven’t figured out how to do it, aside from pain-stakingly converting the image to a video (which takes 2x as long as the length of my videos !) and then superimposing the two videos onto it in another rendering step.
Any tips ? Thank you !
Update :
Thanks to LordNeckbeard’s help, I was able to achieve my desired result with a single ffmpeg call ! Unfortunately, encoding is quite slow, taking 6 seconds to encode 1 second of video. I believe this is caused by the background image. Any tips on speeding up encoding ? Here’s the ffmpeg log :
MacBook-Pro:Video archagon$ ffmpeg -loop 1 -i underlay.png -i test-slide-video-short.flv -i test-speaker-video-short.flv -filter_complex "[1:0]scale=400:-1[a];[2:0]scale=320:-1[b];[0:0][a]overlay=0:0[c];[c][b]overlay=0:0" -shortest -t 5 -an output.mp4
ffmpeg version 1.0 Copyright (c) 2000-2012 the FFmpeg developers
built on Nov 14 2012 16:18:58 with Apple clang version 4.0 (tags/Apple/clang-421.0.60) (based on LLVM 3.1svn)
configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-libtheora --enable-libschroedinger --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libspeex --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --arch=x86_64 --enable-yasm --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
libavutil 51. 73.101 / 51. 73.101
libavcodec 54. 59.100 / 54. 59.100
libavformat 54. 29.104 / 54. 29.104
libavdevice 54. 2.101 / 54. 2.101
libavfilter 3. 17.100 / 3. 17.100
libswscale 2. 1.101 / 2. 1.101
libswresample 0. 15.100 / 0. 15.100
libpostproc 52. 0.100 / 52. 0.100
Input #0, image2, from 'underlay.png':
Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
Stream #0:0: Video: png, rgb24, 1024x768, 25 fps, 25 tbr, 25 tbn, 25 tbc
Input #1, flv, from 'test-slide-video-short.flv':
Metadata:
author :
copyright :
description :
keywords :
rating :
title :
presetname : Custom
videodevice : VGA2USB Pro V3U30343
videokeyframe_frequency: 5
canSeekToEnd : false
createdby : FMS 3.5
creationdate : Mon Aug 16 16:35:34 2010
encoder : Lavf54.29.104
Duration: 00:50:32.75, start: 0.000000, bitrate: 90 kb/s
Stream #1:0: Video: vp6f, yuv420p, 640x480, 153 kb/s, 8 tbr, 1k tbn, 1k tbc
Input #2, flv, from 'test-speaker-video-short.flv':
Metadata:
author :
copyright :
description :
keywords :
rating :
title :
presetname : Custom
videodevice : Microsoft DV Camera and VCR
videokeyframe_frequency: 5
audiodevice : Microsoft DV Camera and VCR
audiochannels : 1
audioinputvolume: 75
canSeekToEnd : false
createdby : FMS 3.5
creationdate : Mon Aug 16 16:35:34 2010
encoder : Lavf54.29.104
Duration: 00:50:38.05, start: 0.000000, bitrate: 238 kb/s
Stream #2:0: Video: vp6f, yuv420p, 320x240, 204 kb/s, 25 tbr, 1k tbn, 1k tbc
Stream #2:1: Audio: mp3, 22050 Hz, mono, s16, 32 kb/s
File 'output.mp4' already exists. Overwrite ? [y/N] y
using cpu capabilities: none!
[libx264 @ 0x7fa84c02f200] profile High, level 3.1
[libx264 @ 0x7fa84c02f200] 264 - core 119 - H.264/MPEG-4 AVC codec - Copyleft 2003-2011 - 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 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 : Lavf54.29.104
Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1024x768, q=-1--1, 25 tbn, 25 tbc
Stream mapping:
Stream #0:0 (png) -> overlay:main
Stream #1:0 (vp6f) -> scale
Stream #2:0 (vp6f) -> scale
overlay -> Stream #0:0 (libx264)
Press [q] to stop, [?] for help
Update 2 :
It works ! One important tweak was to move the underlay.png input to the end of the input list. This increased performance substantially. Here’s my final ffmpeg call. (The maps at the end aren’t required for this particular arrangement, but I sometimes have a few extra audio inputs that I want to map to my output.)
ffmpeg
-i VideoOne.flv
-i VideoTwo.flv
-loop 1 -i Underlay.png
-filter_complex "[2:0] [0:0] overlay=20:main_h/2-overlay_h/2 [overlay];[overlay] [1:0] overlay=main_w-overlay_w-20:main_h/2-overlay_h/2 [output]"
-map [output]:v
-map 0:a
OutputVideo.m4v