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• FFMPEG recode clip1 to match clip2 for concat demux

  21 novembre 2020, par Gert Gottschalk

  I want to concat two video clips using ffmpeg concat. To use concat demuxer both should have same codec settings. clip2 is much shorter so I want to recode it to match clip1. Initially clip2 had tbn not matching and I adjusted that with '-video_track_timescale 50000'. Still the concat video after the cut into clip2 is garbled (audio seems OK)

  


  This is what ffprobe tells for clip1 :

  


  ffprobe version N-80251-g0c7fa15 Copyright (c) 2007-2016 the FFmpeg developers
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  configuration: --prefix=/home/tools/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/home/tools/ffmpeg_build/include --extra-ldflags=-L/home/tools/ffmpeg_build/lib --bindir=/home/tools/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree
  libavutil      55. 24.100 / 55. 24.100
  libavcodec     57. 45.100 / 57. 45.100
  libavformat    57. 37.101 / 57. 37.101
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 46.101 /  6. 46.101
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'clip1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 1
    compatible_brands: isomavc1
    creation_time   : 2020-11-09 01:16:52
  Duration: 01:23:09.33, start: 0.000000, bitrate: 2279 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 2080 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc (default)
    Metadata:
      creation_time   : 2020-11-09 01:16:52
      handler_name    : 11.07_21-45_ard_90_TVOON_DE.mpg.HD_video.h264@GPAC0.5.2-DEV-revVersion: 0.5.2-426-gc5ad4e4+dfsg5-1ubuntu0.1
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 196 kb/s (default)
    Metadata:
      creation_time   : 2020-11-09 01:17:45
      handler_name    : 11.07_21-45_ard_90_TVOON_DE.mpg.HD.aac@GPAC0.5.2-DEV-revVersion: 0.5.2-426-gc5ad4e4+dfsg5-1ubuntu0.1


  


  From clip2

  


  ffprobe version N-80251-g0c7fa15 Copyright (c) 2007-2016 the FFmpeg developers
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  configuration: --prefix=/home/tools/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/home/tools/ffmpeg_build/include --extra-ldflags=-L/home/tools/ffmpeg_build/lib --bindir=/home/tools/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree
  libavutil      55. 24.100 / 55. 24.100
  libavcodec     57. 45.100 / 57. 45.100
  libavformat    57. 37.101 / 57. 37.101
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 46.101 /  6. 46.101
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'clip2.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.37.101
    comment         :  
  Duration: 00:18:42.02, start: 0.000000, bitrate: 1693 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1553 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 130 kb/s (default)
    Metadata:
      handler_name    : SoundHandler


  


  Then for concat :

  


  /home/tools/bin/ffmpeg -f concat -i list.files  -y clip12.mp4


  


  The only gap is with
clip1 : 2080 kb/s
clip2 : 1553 kb/s

  


  Is that significant ?

  


  If yes, how to recode clip2 to match and result in concat clip12 being clean ?

  


  EDIT (Per feedback from llogan) :

  


  Probing input clips with latest ffprobe.

  


  Clip1 :

  


  ffprobe version N-54874-ga1553b0cfb-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2007-2020 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 60.100 / 56. 60.100
  libavcodec     58.112.101 / 58.112.101
  libavformat    58. 64.100 / 58. 64.100
  libavdevice    58. 11.102 / 58. 11.102
  libavfilter     7. 88.102 /  7. 88.102
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'clip1.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 1
    compatible_brands: isomavc1
    creation_time   : 2020-11-09T01:16:52.000000Z
  Duration: 01:23:09.33, start: 0.000000, bitrate: 2279 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 2080 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc (default)
    Metadata:
      creation_time   : 2020-11-09T01:16:52.000000Z
      handler_name    : 11.07_21-45_ard_90_TVOON_DE.mpg.HD_video.h264@GPAC0.5.2-DEV-revVersion: 0.5.2-426-gc5ad4e4+dfsg5-1ubuntu0.1
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 196 kb/s (default)
    Metadata:
      creation_time   : 2020-11-09T01:17:45.000000Z
      handler_name    : 11.07_21-45_ard_90_TVOON_DE.mpg.HD.aac@GPAC0.5.2-DEV-revVersion: 0.5.2-426-gc5ad4e4+dfsg5-1ubuntu0.1


  


  Command & log to change clip2 :

  


  /usr/share/ffmpeg.4.3.1//ffmpeg-git-20201104-amd64-static/ffmpeg -i clip2.avi -ss 00:12:55  -t 00:05:48 -c:v libx264 -profile:v main -video_track_timescale 50k -c:a copy -y clip2.mp4 2> ffmpeg_clip2.log
ffmpeg version N-54874-ga1553b0cfb-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 8 (Debian 8.3.0-6)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libvmaf --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libdav1d --enable-libxvid --enable-libzvbi --enable-libzimg
  libavutil      56. 60.100 / 56. 60.100
  libavcodec     58.112.101 / 58.112.101
  libavformat    58. 64.100 / 58. 64.100
  libavdevice    58. 11.102 / 58. 11.102
  libavfilter     7. 88.102 /  7. 88.102
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, avi, from 'clip2.avi':
  Metadata:
    comment         :  
    encoder         : Lavf58.42.100
    encoded_by      : www.onlinetvrecorder.com
  Duration: 00:35:48.90, start: 0.000000, bitrate: 2243 kb/s
    Stream #0:0: Video: h264 (Main) (H264 / 0x34363248), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], 2034 kb/s, 50 fps, 50 tbr, 50 tbn, 100 tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 192 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame=    0 fps=0.0 q=0.0 size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A  
...
frame=    0 fps=0.0 q=0.0 size=       0kB time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A
[libx264 @ 0x71fb740] using SAR=1/1
[libx264 @ 0x71fb740] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3
[libx264 @ 0x71fb740] profile Main, level 3.2, 4:2:0, 8-bit
[libx264 @ 0x71fb740] 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=0x1:0x111 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=0 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 'clip2.mp4':
  Metadata:
    comment         :  
    encoded_by      : www.onlinetvrecorder.com
    encoder         : Lavf58.64.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 50 fps, 50k tbn, 50 tbc
    Metadata:
      encoder         : Lavc58.112.101 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
    Stream #0:1: Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s
frame=   15 fps=0.4 q=0.0 size=       0kB time=00:00:00.31 bitrate=   1.2kbits/s speed=0.00806x    
...
frame=17400 fps= 73 q=-1.0 Lsize=   62382kB time=00:05:47.97 bitrate=1468.6kbits/s speed=1.47x    
video:53846kB audio:8156kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.611439%
[libx264 @ 0x71fb740] frame I:157   Avg QP:18.21  size: 42082
[libx264 @ 0x71fb740] frame P:5607  Avg QP:22.21  size:  6677
[libx264 @ 0x71fb740] frame B:11636 Avg QP:23.93  size:   953
[libx264 @ 0x71fb740] consecutive B-frames:  8.3%  6.0%  5.0% 80.8%
[libx264 @ 0x71fb740] mb I  I16..4: 47.5%  0.0% 52.5%
[libx264 @ 0x71fb740] mb P  I16..4:  5.7%  0.0%  1.1%  P16..4: 35.4%  6.2%  3.0%  0.0%  0.0%    skip:48.4%
[libx264 @ 0x71fb740] mb B  I16..4:  0.2%  0.0%  0.0%  B16..8: 21.0%  0.4%  0.0%  direct: 0.5%  skip:77.9%  L0:45.1% L1:53.8% BI: 1.2%
[libx264 @ 0x71fb740] coded y,uvDC,uvAC intra: 24.6% 38.3% 6.0% inter: 2.8% 4.7% 0.0%
[libx264 @ 0x71fb740] i16 v,h,dc,p: 43% 24% 15% 18%
[libx264 @ 0x71fb740] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 26% 20% 19%  6%  7%  6%  6%  6%  4%
[libx264 @ 0x71fb740] i8c dc,h,v,p: 57% 20% 20%  4%
[libx264 @ 0x71fb740] Weighted P-Frames: Y:0.5% UV:0.4%
[libx264 @ 0x71fb740] ref P L0: 70.3% 12.1% 14.0%  3.6%  0.0%
[libx264 @ 0x71fb740] ref B L0: 92.9%  5.9%  1.2%
[libx264 @ 0x71fb740] ref B L1: 97.5%  2.5%
[libx264 @ 0x71fb740] kb/s:1267.54


  


  I'm observing mismatch in what I assume is the audio channel.

  


  Clip1 :

  


  /usr/share/ffmpeg.4.3.1//ffmpeg-git-20201104-amd64-static/ffprobe  clip1.mp4
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 2080 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc (default)
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 196 kb/s (default)


  


  Clip2 :

  


  /usr/share/ffmpeg.4.3.1//ffmpeg-git-20201104-amd64-static/ffprobe  clip2.mp4 
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 1267 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc (default)
    Stream #0:1(und): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 192 kb/s (default)


  


  Probably need to match audio channel. I noticed that the concat too a long time. I was expecting the concat to just do copying and not re-rendering.

  


• FFMPEG changes speed when concat 2 or more different videos

  13 novembre 2020, par Daniel Santos Neto

  I am using this code

  


  ffmpeg   -y  -re -i "/myvideos/countdown10.mp4"   -re -i "/myvideos/video_218.mp4"  -re -i "/myvideos/video_220.mp4"   -re -i "/myvideos/video_221.mp4"  -re -i "/myvideos/video_222.mp4"   -re -i "/myvideos/countdown10.mp4"  -re -i '/myvideos/watermark.png'  -filter_complex " [0:v] [0:a]   [1:v] [1:a]   [2:v] [2:a]   [3:v] [3:a]   [4:v] [4:a]   [5:v] [5:a]  concat=n=6:v=1:a=1:unsafe=1 [vv] [a]; [vv][6:v]overlay=W-w-0:0[v]" -map "[v]" -map "[a]"  -preset veryfast -vcodec h264 -acodec aac -strict -2 -max_muxing_queue_size 1024 -y -s 1280x720  -ar 44100 -f flv rtmp://server/live/5fa3731d4f8a6_159


  


  the problem is, when I run it the process speed is a lot faster then the videos length, so I got disconnected from my livestream before the live finishes.

  


  I guess it is something related to the bit rates.

  


  also I notice depends on what video is transcoding the speed floats between 0.9x and 3.7x

  


  frame= 4481 fps= 76 q=-1.0 Lsize= 16857kB time=00:03:13.21 bitrate= 714.7kbits/s dup=0 drop=393 speed=3.29x

  


  Edited :

  


  Complete log file :

  


  avideo@ubuntu:~$ ffmpeg    -re -i "/var/www/gdrive/htdocs/YouPHPTube-Encoder/videos/videosListToLive/countdown10.mp4"   -re -i "/var/www/gdrive/htdocs/YouPHPTube-Encoder/videos/videosListToLive/192.168.1.4/video_222.mp4" -filter_complex " [0:v] [0:a]   [1:v] [1:a] concat=n=2:v=1:a=1:unsafe=1 [v] [a]" -map "[v]" -map "[a]"   -preset veryfast  -vcodec h264 -acodec aac -strict -2 -max_muxing_queue_size 1024 -y -s 1280x720 -ar 44100  -f flv rtmp://encoder.gdrive.local/live?p=f321d14cdeeb7cded7489f504fa8862b/5fa3731d4f8a6_160
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 '/var/www/gdrive/htdocs/YouPHPTube-Encoder/videos/videosListToLive/countdown10.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:10.02, start: 0.000000, bitrate: 122 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 83 kb/s, 5 fps, 5 tbr, 10240 tbn, 10 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 35 kb/s (default)
    Metadata:
      handler_name    : IsoMedia File Produced by Google, 5-11-2011
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from '/var/www/gdrive/htdocs/YouPHPTube-Encoder/videos/videosListToLive/192.168.1.4/video_222.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:30.60, start: 0.000000, bitrate: 37 kb/s
    Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 26 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
    Metadata:
      handler_name    : ISO Media file produced by Google Inc. Created on: 10/16/2018.
    Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 2 kb/s (default)
    Metadata:
      handler_name    : ISO Media file produced by Google Inc. Created on: 10/16/2018.
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 @ 0x5645453b7a80] using SAR=1/1B time=-577014:32:22.77 bitrate=  -0.0kbits/s speed=N/A
[libx264 @ 0x5645453b7a80] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x5645453b7a80] profile High, level 3.1
[libx264 @ 0x5645453b7a80] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=1 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=2 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=6 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=1 keyint=250 keyint_min=5 scenecut=40 intra_refresh=0 rc_lookahead=10 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, flv, to 'rtmp://encoder.gdrive.local/live?p=f321d14cdeeb7cded7489f504fa8862b/5fa3731d4f8a6_160':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) ([7][0][0][0] / 0x0007), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 5 fps, 1k tbn, 5 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) ([10][0][0][0] / 0x000A), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      encoder         : Lavc58.54.100 aac
[flv @ 0x5645453ae580] Failed to update header with correct duration. 49.3kbits/s dup=0 drop=751 speed=1.33x
[flv @ 0x5645453ae580] Failed to update header with correct filesize.
frame=  205 fps=6.7 q=-1.0 Lsize=     250kB time=00:00:40.58 bitrate=  50.5kbits/s dup=0 drop=762 speed=1.33x
video:164kB audio:53kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 15.473391%
[libx264 @ 0x5645453b7a80] frame I:2     Avg QP: 4.62  size: 10450
[libx264 @ 0x5645453b7a80] frame P:58    Avg QP:10.06  size:  1457
[libx264 @ 0x5645453b7a80] frame B:145   Avg QP:11.12  size:   427
[libx264 @ 0x5645453b7a80] consecutive B-frames:  4.9%  1.0%  4.4% 89.8%
[libx264 @ 0x5645453b7a80] mb I  I16..4: 91.4%  2.8%  5.7%
[libx264 @ 0x5645453b7a80] mb P  I16..4:  8.4%  0.4%  0.1%  P16..4:  2.0%  0.3%  0.1%  0.0%  0.0%    skip:88.6%
[libx264 @ 0x5645453b7a80] mb B  I16..4:  0.2%  0.1%  0.0%  B16..8:  0.9%  0.1%  0.0%  direct: 4.7%  skip:94.0%  L0:33.9% L1:63.4% BI: 2.7%
[libx264 @ 0x5645453b7a80] 8x8 transform intra:5.5% inter:24.0%
[libx264 @ 0x5645453b7a80] coded y,uvDC,uvAC intra: 4.7% 22.9% 19.5% inter: 0.2% 4.2% 0.3%
[libx264 @ 0x5645453b7a80] i16 v,h,dc,p: 94%  4%  2%  0%
[libx264 @ 0x5645453b7a80] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 31% 18% 37%  3%  2%  3%  2%  2%  1%
[libx264 @ 0x5645453b7a80] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 38% 20% 21%  5%  3%  4%  3%  4%  3%
[libx264 @ 0x5645453b7a80] i8c dc,h,v,p: 78%  8% 12%  2%
[libx264 @ 0x5645453b7a80] Weighted P-Frames: Y:20.7% UV:20.7%
[libx264 @ 0x5645453b7a80] kb/s:32.64
[aac @ 0x564545421540] Qavg: 61548.156
avideo@ubuntu:~$


  


  Also here is a video where you can see the process

  


  https://tutorials.avideo.com/video/102/ffmpeg-changes-speed-when-concat-2-or-more-different-videos

  


  this live should have exactly 40 seconds but finishes before then that

  


  also look at this time position https://tutorials.avideo.com/video/102/ffmpeg-changes-speed-when-concat-2-or-more-different-videos?t=12

  


  the speed changes from speed=0.9 to speed=1.9

  


  speed=0.9 to speed=1.9

  


  EDITED 2 :

  


  I tried the FPS command as suggested and still the problem

  


  avideo@ubuntu:~$ ffmpeg    -re -i "http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/index.m3u8?token=eyJzYWx0IjoiaHR0cDpcL1wvMTkyLjE2OC4xLjRcL1lvdVBIUFR1YmVcLyIsInRva2VuVGltZU91dCI6IjIxNjAwIiwiZmlsZW5hbWUiOiJfWVBUdW5pcWlkXzVmODBjNTQ3NDIxMDU3LjI0MDU2MDE1IiwidGltZSI6MTYwNTI4MzExN30="   -re -i "http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5fa3f4e37ffb65.33430678_720.mp4?token=eyJzYWx0IjoiaHR0cDpcL1wvMTkyLjE2OC4xLjRcL1lvdVBIUFR1YmVcLyIsInRva2VuVGltZU91dCI6IjIxNjAwIiwiZmlsZW5hbWUiOiJfWVBUdW5pcWlkXzVmYTNmNGUzN2ZmYjY1LjMzNDMwNjc4IiwidGltZSI6MTYwNTI4MzExN30="   -re -i '/var/www/gdrive/htdocs/YouPHPTube-Encoder/videos/videosListToLive/192.168.1.4/watermark.png'  -filter_complex "  [0]setdar=16/9,scale=1280:720, fps=30[0:v];     [1]setdar=16/9,scale=1280:720, fps=30[1:v];     [0:v] [0:a]     [1:v] [1:a]   concat=n=2:v=1:a=1:unsafe=1 [vv] [a]; [vv][2:v]overlay=W-w-0:0[v]" -map "[v]" -map "[a]"   -c:v libx264 -b:v 3000k -maxrate 3000k -bufsize 6000k -g 50 -c:a aac -b:a 128k -ac 2 -s 1280x720  -ar 44100   -f flv rtmp://encoder.gdrive.local/live?p=f321d14cdeeb7cded7489f504fa8862b/5fa3731d4f8a6_161
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
[hls @ 0x5627c50f2800] Skip ('#EXT-X-VERSION:3')
[hls @ 0x5627c50f2800] Opening 'http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/res240/index.m3u8?token=eyJzYWx0IjoiaHR0cDpcL1wvMTkyLjE2OC4xLjRcL1lvdVBIUFR1YmVcLyIsInRva2VuVGltZU91dCI6IjIxNjAwIiwiZmlsZW5hbWUiOiJfWVBUdW5pcWlkXzVmODBjNTQ3NDIxMDU3LjI0MDU2MDE1IiwidGltZSI6MTYwNTI4MzExN30=' for reading
[hls @ 0x5627c50f2800] Skip ('#EXT-X-VERSION:3')
[http @ 0x5627c50fa940] Opening 'http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/res360/index.m3u8?token=eyJzYWx0IjoiaHR0cDpcL1wvMTkyLjE2OC4xLjRcL1lvdVBIUFR1YmVcLyIsInRva2VuVGltZU91dCI6IjIxNjAwIiwiZmlsZW5hbWUiOiJfWVBUdW5pcWlkXzVmODBjNTQ3NDIxMDU3LjI0MDU2MDE1IiwidGltZSI6MTYwNTI4MzExN30=' for reading
[hls @ 0x5627c50f2800] Skip ('#EXT-X-VERSION:3')
[hls @ 0x5627c50f2800] Opening 'http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/enc_5f80c54914f03.key' for reading
[hls @ 0x5627c50f2800] Opening 'crypto+http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/res240/index0.ts' for reading
[hls @ 0x5627c50f2800] Opening 'http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/enc_5f80c54914f03.key' for reading
[hls @ 0x5627c50f2800] Opening 'crypto+http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/res360/index0.ts' for reading
Input #0, hls, from 'http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/index.m3u8?token=eyJzYWx0IjoiaHR0cDpcL1wvMTkyLjE2OC4xLjRcL1lvdVBIUFR1YmVcLyIsInRva2VuVGltZU91dCI6IjIxNjAwIiwiZmlsZW5hbWUiOiJfWVBUdW5pcWlkXzVmODBjNTQ3NDIxMDU3LjI0MDU2MDE1IiwidGltZSI6MTYwNTI4MzExN30=':
  Duration: 00:00:13.21, start: 1.460111, bitrate: 0 kb/s
  Program 0
    Metadata:
      variant_bitrate : 300000
    Stream #0:0: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 426x240 [SAR 640:639 DAR 16:9], 24 fps, 24 tbr, 90k tbn, 48 tbc
    Metadata:
      variant_bitrate : 300000
    Stream #0:1: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp
    Metadata:
      variant_bitrate : 300000
  Program 1
    Metadata:
      variant_bitrate : 600000
    Stream #0:2: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p, 640x360 [SAR 1:1 DAR 16:9], 24 fps, 24 tbr, 90k tbn, 48 tbc
    Metadata:
      variant_bitrate : 600000
    Stream #0:3: Audio: aac (LC) ([15][0][0][0] / 0x000F), 44100 Hz, stereo, fltp
    Metadata:
      variant_bitrate : 600000
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5fa3f4e37ffb65.33430678_720.mp4?token=eyJzYWx0IjoiaHR0cDpcL1wvMTkyLjE2OC4xLjRcL1lvdVBIUFR1YmVcLyIsInRva2VuVGltZU91dCI6IjIxNjAwIiwiZmlsZW5hbWUiOiJfWVBUdW5pcWlkXzVmYTNmNGUzN2ZmYjY1LjMzNDMwNjc4IiwidGltZSI6MTYwNTI4MzExN30=':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
  Duration: 00:00:30.60, start: 0.000000, bitrate: 37 kb/s
    Stream #1:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 26 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
    Metadata:
      handler_name    : ISO Media file produced by Google Inc. Created on: 10/16/2018.
    Stream #1:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 2 kb/s (default)
    Metadata:
      handler_name    : ISO Media file produced by Google Inc. Created on: 10/16/2018.
Input #2, png_pipe, from '/var/www/gdrive/htdocs/YouPHPTube-Encoder/videos/videosListToLive/192.168.1.4/watermark.png':
  Duration: N/A, bitrate: N/A
    Stream #2:0: Video: png, rgba(pc), 1280x720 [SAR 3780:3780 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
Stream mapping:
  Stream #0:0 (h264) -> setdar
  Stream #0:1 (aac) -> concat:in0:a0
  Stream #1:0 (h264) -> setdar
  Stream #1:1 (aac) -> concat:in1:a0
  Stream #2:0 (png) -> overlay:overlay
  overlay -> Stream #0:0 (libx264)
  concat:out:a0 -> Stream #0:1 (aac)
Press [q] to stop, [?] for help
[libx264 @ 0x5627c5267f40] using SAR=1/1
[libx264 @ 0x5627c5267f40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x5627c5267f40] profile High, level 3.1
[libx264 @ 0x5627c5267f40] 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=50 keyint_min=5 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=cbr mbtree=1 bitrate=3000 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_maxrate=3000 vbv_bufsize=6000 nal_hrd=none filler=0 ip_ratio=1.40 aq=1:1.00
Output #0, flv, to 'rtmp://encoder.gdrive.local/live?p=f321d14cdeeb7cded7489f504fa8862b/5fa3731d4f8a6_161':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) ([7][0][0][0] / 0x0007), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 3000 kb/s, 30 fps, 1k tbn, 30 tbc (default)
    Metadata:
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 3000000/0/3000000 buffer size: 6000000 vbv_delay: -1
    Stream #0:1: Audio: aac (LC) ([10][0][0][0] / 0x000A), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      encoder         : Lavc58.54.100 aac
[hls @ 0x5627c50f2800] Opening 'crypto+http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/res240/index1.ts' for reading
[hls @ 0x5627c50f2800] No longer receiving playlist 1 ('http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/res360/index.m3u8?token=eyJzYWx0IjoiaHR0cDpcL1wvMTkyLjE2OC4xLjRcL1lvdVBIUFR1YmVcLyIsInRva2VuVGltZU91dCI6IjIxNjAwIiwiZmlsZW5hbWUiOiJfWVBUdW5pcWlkXzVmODBjNTQ3NDIxMDU3LjI0MDU2MDE1IiwidGltZSI6MTYwNTI4MzExN30=')
[hls @ 0x5627c50f2800] Opening 'crypto+http://192.168.1.4/YouPHPTube/videos/_YPTuniqid_5f80c547421057.24056015/res240/index2.ts' for reading
[flv @ 0x5627c52635c0] Failed to update header with correct duration.10.4kbits/s speed=1.43x
[flv @ 0x5627c52635c0] Failed to update header with correct filesize.
frame= 1313 fps= 43 q=-1.0 Lsize=    5937kB time=00:00:43.81 bitrate=1110.1kbits/s speed=1.43x
video:5662kB audio:218kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.976283%
[libx264 @ 0x5627c5267f40] frame I:70    Avg QP: 4.15  size: 27705
[libx264 @ 0x5627c5267f40] frame P:423   Avg QP: 4.16  size:  6930
[libx264 @ 0x5627c5267f40] frame B:820   Avg QP: 1.56  size:  1130
[libx264 @ 0x5627c5267f40] consecutive B-frames: 13.6%  7.9%  4.8% 73.7%
[libx264 @ 0x5627c5267f40] mb I  I16..4: 69.2% 24.3%  6.4%
[libx264 @ 0x5627c5267f40] mb P  I16..4:  2.0%  9.4%  1.6%  P16..4:  1.7%  0.3%  0.1%  0.0%  0.0%    skip:85.0%
[libx264 @ 0x5627c5267f40] mb B  I16..4:  0.1%  0.3%  0.2%  B16..8:  1.0%  0.1%  0.0%  direct: 0.6%  skip:97.6%  L0:57.9% L1:40.1% BI: 2.0%
[libx264 @ 0x5627c5267f40] 8x8 transform intra:45.7% inter:71.9%
[libx264 @ 0x5627c5267f40] coded y,uvDC,uvAC intra: 36.1% 46.9% 43.4% inter: 0.4% 1.1% 0.7%
[libx264 @ 0x5627c5267f40] i16 v,h,dc,p: 93%  4%  3%  0%
[libx264 @ 0x5627c5267f40] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 65%  8% 16%  1%  2%  3%  1%  2%  2%
[libx264 @ 0x5627c5267f40] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 50% 20% 10%  3%  4%  5%  3%  4%  2%
[libx264 @ 0x5627c5267f40] i8c dc,h,v,p: 61% 10% 25%  4%
[libx264 @ 0x5627c5267f40] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x5627c5267f40] ref P L0: 72.6%  2.7% 18.0%  6.7%
[libx264 @ 0x5627c5267f40] ref B L0: 89.1%  9.4%  1.5%
[libx264 @ 0x5627c5267f40] ref B L1: 98.0%  2.0%
[libx264 @ 0x5627c5267f40] kb/s:1059.69
[aac @ 0x5627c51d25c0] Qavg: 46028.516
avideo@ubuntu:~$


  


• File (mp3) concatenation issues using FFmpeg

  17 novembre 2020, par Giorgio Robino

  I want to concatenate some MP3 files using the FFmpeg concatenation protocol.

  


  Here is a successful try :

  


  $ ffmpeg -loglevel panic -i "concat:audio/it/ci.mp3|audio/it/èsse.mp3|audio/it/cu.mp3|audio/it/u.mp3|audio/it/tre.mp3|audio/it/zero.mp3|audio/it/cinque.mp3|audio/it/quattro.mp3|audio/it/tre.mp3|audio/it/otto.mp3|audio/it/tre.mp3" -c copy audio/it/CSQU3054383.mp3 -y

$ ll audio/it/CSQU3054383.mp3
-rw-rw-r-- 1 giorgio 26K Nov  9 16:16 audio/it/CSQU3054383.mp3


  


  So far, all is OK !

  


  BTW, all (Mp3) files have the same codecs, so MP3 FFmpeg concatenation protocol runs as expected !

  


  ---

  


  Now, I want to insert a pause file audio/it/PAUSE_2.mp3, between each previous files :

  


  $ ffmpeg -loglevel panic -i "concat:audio/it/ci.mp3|audio/it/PAUSE_2.mp3|audio/it/èsse.mp3|audio/it/PAUSE_2.mp3|audio/it/cu.mp3|audio/it/PAUSE_2.mp3|audio/it/u.mp3|audio/it/PAUSE_2.mp3|audio/it/tre.mp3|audio/it/PAUSE_2.mp3|audio/it/zero.mp3|audio/it/PAUSE_2.mp3|audio/it/cinque.mp3|audio/it/PAUSE_2.mp3|audio/it/quattro.mp3|audio/it/PAUSE_2.mp3|audio/it/tre.mp3|audio/it/PAUSE_2.mp3|audio/it/otto.mp3|audio/it/PAUSE_2.mp3|audio/it/tre.mp3" -c copy audio/it/CSQU3054383.mp3 -y
$


  


  This command run apparently without any error, but the output file (audio/it/CSQU3054383.mp3) is not generated at all.

  


  **Question 1 (minor) :
  

  


  Why doesn't FFmpeg report any error and doesn't generate the expected output ?**

  


  In fact, I already experienced that FFmpeg, in some circumstances, fails without saying why :(

  


  ---

  


  I suspect the problem happens because the file audio/it/PAUSE_2.mp3 doesn't have a constant bit rate (CBR), as other files, e.g. :

  


  $ mediainfo  audio/it/ci.mp3
General
Complete name                            : audio/it/ci.mp3
Format                                   : MPEG Audio
File size                                : 2.06 KiB
Duration                                 : 528 ms
Overall bit rate mode                    : Constant
Overall bit rate                         : 32.0 kb/s

Audio
Format                                   : MPEG Audio
Format version                           : Version 2
Format profile                           : Layer 3
Duration                                 : 528 ms
Bit rate mode                            : Constant
Bit rate                                 : 32.0 kb/s
Channel(s)                               : 1 channel
Sampling rate                            : 24.0 kHz
Frame rate                               : 41.667 FPS (576 SPF)
Compression mode                         : Lossy
Stream size                              : 2.06 KiB (100%)

$ ffprobe audio/it/ci.mp3
ffprobe version 3.4.8-0ubuntu0.2 Copyright (c) 2007-2020 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix=/usr --extra-version=0ubuntu0.2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
[mp3 @ 0x564491288080] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'audio/it/ci.mp3':
  Duration: 00:00:00.53, start: 0.000000, bitrate: 32 kb/s
    Stream #0:0: Audio: mp3, 24000 Hz, mono, s16p, 32 kb/s



  


  Instead, the inserted pause file has a variable bit rate, as mediainfo states :

  


  $ mediainfo audio/it/PAUSE_2.mp3
General
Complete name                            : audio/it/PAUSE_2.mp3
Format                                   : MPEG Audio
File size                                : 8.29 KiB
Overall bit rate mode                    : Variable
Writing library                          : LAME3.100

Audio
Format                                   : MPEG Audio
Format version                           : Version 2
Format profile                           : Layer 3
Bit rate mode                            : Variable
Channel(s)                               : 1 channel
Sampling rate                            : 24.0 kHz
Compression mode                         : Lossy
Stream size                              : 8.06 KiB (97%)
Writing library                          : LAME3.100


  


  Here my Bash script I used to generate the pause :

  


  $ cat com/pause&#xA;#!/bin/bash&#xA;&#xA;# https://ffmpeg.org/ffmpeg-filters.html#toc-anullsrc&#xA;# https://ffmpeg.org/ffmpeg-utils.html#toc-Examples-1&#xA;&#xA;if [ $# -eq 0 ]&#xA;  then&#xA;    echo&#xA;    echo "create a pause, a silence audio file (MP3) of specified number of milliseconds"&#xA;    echo&#xA;    echo "usage: $0 <time duration="duration"> <directory path="path">"&#xA;    echo&#xA;    echo "example: $0 2"&#xA;    echo "example: $0 0.5 tmp/"&#xA;    echo&#xA;    exit&#xA;fi&#xA;&#xA;timeDuration=$1&#xA;directoryPath=$2&#xA;&#xA;suffix=mp3&#xA;&#xA;# https://trac.ffmpeg.org/wiki/Limiting%20the%20output%20bitrate&#xA;#https://trac.ffmpeg.org/wiki/Encode/MP3&#xA;bitrate=32k&#xA;samplingRate=24000&#xA;outputFile="${directoryPath}PAUSE_${timeDuration}.${suffix}"&#xA;&#xA;  #-b:a $bitrate -minrate $bitrate -maxrate $bitrate -bufsize $bitrate \&#xA;ffmpeg \&#xA;  -f lavfi \&#xA;  -i anullsrc=r=$samplingRate:cl=mono \&#xA;  -t $timeDuration \&#xA;  -b:a $bitrate -minrate $bitrate -maxrate $bitrate \&#xA;  -codec:a libmp3lame \&#xA;  $outputFile -y&#xA;&#xA;echo&#xA;echo "created file: $outputFile"&#xA;echo&#xA;&#xA;</directory></time>

  


  Unfortunately, the created file seems with a variable bit rate and not with a constant bit rate (CBR), as expected ( -b:a ... ) :

  


  $ com/pause 2
ffmpeg version 3.4.8-0ubuntu0.2 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix=/usr --extra-version=0ubuntu0.2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, lavfi, from 'anullsrc=r=24000:cl=mono':
  Duration: N/A, start: 0.000000, bitrate: 192 kb/s
    Stream #0:0: Audio: pcm_u8, 24000 Hz, mono, u8, 192 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_u8 (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
Output #0, mp3, to 'PAUSE_2.mp3':
  Metadata:
    TSSE            : Lavf57.83.100
    Stream #0:0: Audio: mp3 (libmp3lame), 24000 Hz, mono, s16p, 32 kb/s
    Metadata:
      encoder         : Lavc57.107.100 libmp3lame
size=       8kB time=00:00:02.01 bitrate=  33.7kbits/s speed= 192x
video:0kB audio:8kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.870640%

created file: PAUSE_2.mp3


  


  Question 2 :

  


  What's wrong in my Bash script (why doesn't it generate a CBR file ?
How can I generate an silence pause file (silence of N milliseconds) with the exact settings of previous files ?