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• Losing audio quality when merging multiple videos with FFmpeg

  30 mai 2021, par Charly

  I am trying to merge multiple videos (a few seconds each) into one, using FFmpeg.

  


  Merging all at once

  


  I first tried merging all videos with one FFmpeg command, but it only seems to work with up to a certain amount of videos. On my Raspberry Pi 4 (2BG RAM), it worked for 16 videos and broke (ran out of memory ?) while merging 36 videos (command and ouput below)

  


  ffmpeg -i 1Rbrdn1Xp.mp4 -i G7eYqdFPb.mp4 -i -Xo-6ABm3.mp4 -i 6As9IlqbW.mp4 -i tz9tVKFA-.mp4
-i MS6DHZoJE.mp4 -i CeJYs99-G.mp4 -i Hsv5X48IC.mp4 -i Gm_DtjNU4.mp4 -i PZytbInZL.mp4
-i qsIJuvKO2.mp4 -i c5wxGk_Fx.mp4 -i j4K1qA7ih.mp4 -i AIpVWuhGV.mp4 -i yiLk0snSh.mp4
-i q1zmytaXZ.mp4 -i VRwQvLxaW.mp4 -i 0_3yLrokH.mp4 -i fW28LPQsk.mp4 -i La6WsGeE8.mp4
-i FlroQnCHq.mp4 -i c7SiL_qSU.mp4 -i aaGTUMJXD.mp4 -i hvXYBaCSM.mp4 -i CMDaFrWM4.mp4
-i _YAGDRyQN.mp4 -i RQXyshs_o.mp4 -i 96pKlIZxW.mp4 -i HVOOeCUYG.mp4 -i pJFxq7BTx.mp4
-i VxMJQqbK5.mp4 -i mkgbViPTI.mp4 -i zrjj93b5c.mp4 -i AL9oG1F36.mp4 -i IsUnC0NPb.mp4
-i Qhj2bhab9.mp4 -y -filter_complex concat=n=36:v=1:a=1 -vsync 2 kn-dQSN-v.mp4


  


  ffmpeg version 4.1.6-1~deb10u1+rpt1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 8 (Raspbian 8.3.0-6+rpi1)
(...)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1Rbrdn1Xp.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
  Duration: 00:00:08.08, start: 0.000000, bitrate: 602 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 533 kb/s, 57.62 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 22050 Hz, mono, fltp, 64 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'G7eYqdFPb.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
  Duration: 00:00:21.00, start: 0.000000, bitrate: 310 kb/s
    Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 229 kb/s, 59.09 fps, 60 tbr, 15360 tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 22050 Hz, mono, fltp, 72 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
(...)
Stream mapping:
  Stream #0:0 (h264) -> concat:in0:v0
  Stream #0:1 (aac) -> concat:in0:a0
  Stream #1:0 (h264) -> concat:in1:v0
  Stream #1:1 (aac) -> concat:in1:a0
(...)
  concat:out:v0 -> Stream #0:0 (libx264)
  concat:out:a0 -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[libx264 @ 0x17cb5e0] using SAR=1/1   0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A    
[libx264 @ 0x17cb5e0] using cpu capabilities: ARMv6 NEON
[libx264 @ 0x17cb5e0] profile High, level 3.2
[libx264 @ 0x17cb5e0] 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=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=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 'kn-dQSN-v.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 60 fps, 15360 tbn, 60 tbc (default)
    Metadata:
      encoder         : Lavc58.35.100 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), 22050 Hz, mono, fltp, 69 kb/s (default)
    Metadata:
      encoder         : Lavc58.35.100 aac
frame=15952 fps= 52 q=31.0 size=   10240kB time=00:04:33.02 bitrate= 307.3kbits/s speed=0.844x
[h264 @ 0x3472d80] get_buffer() failed40kB time=00:04:33.02 bitrate= 307.3kbits/s speed=0.844x    
[h264 @ 0x3472d80] thread_get_buffer() failed
[h264 @ 0x3472d80] decode_slice_header error
[h264 @ 0x3472d80] no frame!
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x34f54d0] get_buffer() failed
[h264 @ 0x34f54d0] thread_get_buffer() failed
[h264 @ 0x34f54d0] decode_slice_header error
[h264 @ 0x34f54d0] no frame!
[h264 @ 0x3472d80] get_buffer() failed
[h264 @ 0x3472d80] thread_get_buffer() failed
(...)
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x3472d80] reference picture missing during reorder
[h264 @ 0x3472d80] Missing reference picture, default is 65660
[h264 @ 0x34c4540] mmco: unref short failure
[h264 @ 0x34f54d0] get_buffer() failed08kB time=00:04:45.37 bitrate= 316.0kbits/s speed=0.845x    
[h264 @ 0x34f54d0] thread_get_buffer() failed
[h264 @ 0x34f54d0] decode_slice_header error
[h264 @ 0x34f54d0] no frame!
[h264 @ 0x3472d80] decode_slice_header error
[h264 @ 0x3472d80] no frame!
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x34f54d0] mmco: unref short failure
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x3472d80] get_buffer() failed
[h264 @ 0x3472d80] thread_get_buffer() failed
[h264 @ 0x3472d80] decode_slice_header error
[h264 @ 0x3472d80] no frame!
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x3472d80] get_buffer() failed
[h264 @ 0x3472d80] thread_get_buffer() failed
[h264 @ 0x3472d80] decode_slice_header error
[h264 @ 0x3472d80] no frame!
[h264 @ 0x34f54d0] reference picture missing during reorder
    Last message repeated 1 times
[h264 @ 0x34f54d0] Missing reference picture, default is 65708
    Last message repeated 1 times
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x34dccb0] reference picture missing during reorder
[h264 @ 0x34dccb0] Missing reference picture, default is 65716
[h264 @ 0x3472d80] mmco: unref short failure
[h264 @ 0x34f54d0] decode_slice_header error
[h264 @ 0x34f54d0] no frame!
Error while decoding stream #15:0: Invalid data found when processing inputbits/s speed=0.845x    
[h264 @ 0x3480010] get_buffer() failed
[h264 @ 0x3480010] thread_get_buffer() failed
[h264 @ 0x3480010] decode_slice_header error
[h264 @ 0x3480010] no frame!
[h264 @ 0x34c4540] decode_slice_header error
[h264 @ 0x34c4540] no frame!
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x3480010] mmco: unref short failure
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x34c4540] get_buffer() failed
[h264 @ 0x34c4540] thread_get_buffer() failed
[h264 @ 0x34c4540] decode_slice_header error
[h264 @ 0x34c4540] no frame!
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x34c4540] get_buffer() failed
[h264 @ 0x34c4540] thread_get_buffer() failed
[h264 @ 0x34c4540] decode_slice_header error
[h264 @ 0x34c4540] no frame!
[h264 @ 0x34f54d0] decode_slice_header error
[h264 @ 0x34f54d0] no frame!
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x3480010] reference picture missing during reorder
    Last message repeated 1 times
[h264 @ 0x3480010] Missing reference picture, default is 65772
    Last message repeated 1 times
Error while decoding stream #15:0: Invalid data found when processing input
[h264 @ 0x3472d80] reference picture missing during reorder
[h264 @ 0x3472d80] Missing reference picture, default is 65780
[h264 @ 0x34c4540] mmco: unref short failure
av_interleaved_write_frame(): Cannot allocate memory
[mp4 @ 0x295c7e0] Application provided duration: 3689347710924763697 / timestamp: 6291454 is out of range for mov/mp4 format
Segmentation fault


  


  Merging videos 2 by 2

  


  I then tried gradually merging videos into one, using multiple FFmpeg commands.

  


  # Pseudocode
final = merge(clip1, clip2)
final = merge(final, clip3)
final = merge(final, clip4)
final = merge(final, clip5)
...


  


  with each command, looking like this :

  


  ffmpeg -i 1Rbrdn1Xp.mp4 -i G7eYqdFPb.mp4 -y -filter_complex concat=n=2:v=1:a=1 -vsync 2 UMVDl9jki.mp4


  


  ffmpeg -i UMVDl9jki.mp4 -i -Xo-6ABm3.mp4 -y -filter_complex concat=n=2:v=1:a=1 -vsync 2 azE1Uombp.mp4


  


  This works but there is a loss in audio quality on the first clips, and it is slowly improving over time. I am guessing this is due to the first videos being merged more times than the last ones. You can see this effect happen in this video (weird artefacts in the voice).

  


  ---

  


  So, am I doing something wrong ?
  
Is there a way of merging a lot of videos, without running out of memory or worsening the audio quality ?

  


• Adding cover art to video wtih chapters and chapters getting deleted

  31 mai 2021, par throwaway513

  I am trying to add a cover art to a video with chapters.

  


  I added 2 chapters to a video using :

  


  ffmpeg -i 1.mp4 -i Chapters.txt -map_metadata 1 -c copy 2.mp4

  


  but when I try to add cover art it deletes the first chapter and only keeps the second ?

  


  ffmpeg -i 2.mp4 -i image.jpg -map 1 -map 0 -c copy -disposition:0 attached_pic 3.mp4

  


  I also tried mp3tag but the picture doesn't show on the file after adding chapters through ffmpeg. Chapters work fine on 2.mp4 but on 3.mp4 it deletes the first chapter. It also deletes the chapter when I do ffmpeg -i 2.mp4 -c copy any.mp4

  


  Chapter.txt

  


  ;FFMETADATA1
major_brand=isom
minor_version=512
compatible_brands=isomiso2avc1mp41
encoder=Lavf58.12.100

[CHAPTER]
TIMEBASE=1/1000
START=1152352
END=
title=

[CHAPTER]
TIMEBASE=1/1000
START=1378578
END=
title=


  


  ---

  


  C:\Users\Dark\Desktop\ffmpeg\bin>ffmpeg -i 1.mp4 -i Chapters.txt -map_metadata 1 -c copy 2.mp4
ffmpeg version 4.0.2 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 7.3.1 (GCC) 20180722
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
  libavutil      56. 14.100 / 56. 14.100
  libavcodec     58. 18.100 / 58. 18.100
  libavformat    58. 12.100 / 58. 12.100
  libavdevice    58.  3.100 / 58.  3.100
  libavfilter     7. 16.100 /  7. 16.100
  libswscale      5.  1.100 /  5.  1.100
  libswresample   3.  1.100 /  3.  1.100
  libpostproc    55.  1.100 / 55.  1.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001a7335c99c0] stream 0, timescale not set
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    creation_time   : 1970-01-01T00:00:00.000000Z
    encoder         : Lavf52.31.0
  Duration: 00:27:10.00, start: 0.000000, bitrate: 3338 kb/s
    Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, 3120 kb/s, 29.97 fps, 29.97 tbr, 770589.00 tbn, 59.94 tbc (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 103 kb/s (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : SoundHandler
    Stream #0:2: Video: mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 1:1 DAR 16:9], 90k tbr, 90k tbn, 90k tbc
Input #1, ffmetadata, from 'Chapters.txt':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.12.100
  Duration: 504900:42:04.42, start: 0.000000, bitrate: N/A
    Chapter #1:0: start 1152.352000, end 1817642524.416000
    Metadata:
      title           :
    Chapter #1:1: start 1378.578000, end 1817642524.416000
    Metadata:
      title           :
[mp4 @ 000001a733efdfc0] Application provided duration: 1817641372064 is invalid
[mp4 @ 000001a733efdfc0] Application provided duration: 1817641145838 is invalid
Output #0, mp4, to '2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.12.100
    Chapter #0:0: start 1152.352000, end 1817642524.416000
    Metadata:
      title           :
    Chapter #0:1: start 1378.578000, end 1817642524.416000
    Metadata:
      title           :
    Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, q=2-31, 3120 kb/s, 29.97 fps, 29.97 tbr, 770589.00 tbn, 770589.00 tbc (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 103 kb/s (default)
    Metadata:
      creation_time   : 1970-01-01T00:00:00.000000Z
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame=48851 fps=0.0 q=-1.0 Lsize=  642768kB time=00:27:09.96 bitrate=3230.5kbits/s speed=3.04e+03x
video:620855kB audio:20549kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.212700%


  


  ---

  


  C:\Users\Dark\Desktop\ffmpeg\bin>ffmpeg -i 2.mp4 -i image.jpg -map 1 -map 0 -c copy -disposition:0 attached_pic 3.mp4
ffmpeg version 4.0.2 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 7.3.1 (GCC) 20180722
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
  libavutil      56. 14.100 / 56. 14.100
  libavcodec     58. 18.100 / 58. 18.100
  libavformat    58. 12.100 / 58. 12.100
  libavdevice    58.  3.100 / 58.  3.100
  libavfilter     7. 16.100 /  7. 16.100
  libswscale      5.  1.100 /  5.  1.100
  libswresample   3.  1.100 /  3.  1.100
  libpostproc    55.  1.100 / 55.  1.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001cdbdbd9b40] Referenced QT chapter track not found
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.12.100
  Duration: 00:27:10.00, start: 0.000000, bitrate: 3230 kb/s
    Chapter #0:0: start 1152.352000, end 1378.578000
    Metadata:
      title           :
    Chapter #0:1: start 1378.578000, end 1629.996000
    Metadata:
      title           :
    Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, 3120 kb/s, 29.97 fps, 29.97 tbr, 770589.00 tbn, 59.94 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 103 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Input #1, image2, from 'image.jpg':
  Duration: 00:00:00.04, start: 0.000000, bitrate: 24266 kb/s
    Stream #1:0: Video: mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 1:1 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
Output #0, mp4, to '3.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.12.100
    Chapter #0:0: start 1152.352000, end 1378.578000
    Metadata:
      title           :
    Chapter #0:1: start 1378.578000, end 1629.996000
    Metadata:
      title           :
    Stream #0:0: Video: mjpeg (mp4v / 0x7634706D), yuvj444p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 25 tbr, 12800 tbn, 25 tbc
    Stream #0:1(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, q=2-31, 3120 kb/s, 29.97 fps, 29.97 tbr, 770589.00 tbn, 770589.00 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:2(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 103 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #1:0 -> #0:0 (copy)
  Stream #0:0 -> #0:1 (copy)
  Stream #0:1 -> #0:2 (copy)
Press [q] to stop, [?] for help
frame=    1 fps=0.0 q=-1.0 Lq=-1.0 size=  642887kB time=00:27:09.96 bitrate=3231.1kbits/s speed=2.79e+03x
video:620973kB audio:20549kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.212752%


  


• 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. 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.

     


  


  


  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