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• generating silence audio using ffmpeg with specific bitrate and duration time less than one second cannot get the audio with the desired bitrate

  28 août 2018, par bambooom

  I’d like to generate a silence audio file using ffmpeg with specific bitrate and the duration is less than one second. I found that the generated audio file does not have the desired bitrate. But if I expand the duration to 2 seconds, the bitrate seems to be correct.

  For example :

  ffmpeg -f lavfi -i anullsrc=r=22050:cl=mono -t 0.3 -acodec mp3 -ab 48k -y silence.mp3

  The generated silence.mp3’s bitrate seems not 48kb/s :

  $ ffprobe silence.mp3                                                                                           
  
  ffprobe version 3.4.2 Copyright (c) 2007-2018 the FFmpeg developers
  
    built with Apple LLVM version 9.1.0 (clang-902.0.39.1)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --disable-jack --enable-gpl --enable-libmp3lame --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  
    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, mp3, from 'silence.mp3':
  
    Metadata:
  
      encoder         : Lavf57.83.100
  
    Duration: 00:00:00.37, start: 0.050113, bitrate: 52 kb/s
  
      Stream #0:0: Audio: mp3, 22050 Hz, mono, s16p, 48 kb/s

  If the duration is 2 seconds, bitrate seems OK :

  $ ffmpeg -f lavfi -i anullsrc=r=22050:cl=mono -t 2 -acodec mp3 -ab 48k -y silence.mp3
  
  $ ffprobe silence.mp3                                                                                           
  
  ffprobe version 3.4.2 Copyright (c) 2007-2018 the FFmpeg developers
  
    built with Apple LLVM version 9.1.0 (clang-902.0.39.1)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.4.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --disable-jack --enable-gpl --enable-libmp3lame --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  
    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, mp3, from 'silence.mp3':
  
    Metadata:
  
      encoder         : Lavf57.83.100
  
    Duration: 00:00:02.06, start: 0.050113, bitrate: 48 kb/s
  
      Stream #0:0: Audio: mp3, 22050 Hz, mono, s16p, 48 kb/s

  Is there any way to keep the bitrate as desired ?

• Impossible to convert between the formats supported by the filter '...' - Error reinitializing filters

  14 novembre 2023, par Fabien Biller

  I am using this ffmpeg command(values removed for simplicity)

  


  ffmpeg -hwaccel cuvid -c:v h264_cuvid -y -ss 1 -i "FILE0001.MOV" -ss 0 -i "GOPR0621.MP4" -filter_complex 
[0:v][1:v]
  midequalizer
[al];
[al]
  yadif
  lenscorrection
  scale
[vl];
[1:v]
  lenscorrection
  scale
[vr];
[vl][vr]
  hstack=shortest=1 
-an -c:v h264_nvenc -preset slow "output.mp4"


  


  on a machine with a cuda graphics card.

  


  I get

  


  ffmpeg version N-90979-g08032331ac Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 7.3.0 (GCC)
  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. 18.100 / 56. 18.100
  libavcodec     58. 19.100 / 58. 19.100
  libavformat    58. 13.101 / 58. 13.101
  libavdevice    58.  4.100 / 58.  4.100
  libavfilter     7. 21.100 /  7. 21.100
  libswscale      5.  2.100 /  5.  2.100
  libswresample   3.  2.100 /  3.  2.100
  libpostproc    55.  2.100 / 55.  2.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 00000254a8afc0c0] st: 0 edit list: 1 Missing key frame while searching for timestamp: 6006
[mov,mp4,m4a,3gp,3g2,mj2 @ 00000254a8afc0c0] st: 0 edit list 1 Cannot find an index entry before timestamp: 6006.
....
Stream mapping:
  Stream #0:0 (h264_cuvid) -> midequalizer:in0
  Stream #1:0 (h264) -> midequalizer:in1
  Stream #1:0 (h264) -> lenscorrection
  hstack -> Stream #0:0 (h264_nvenc)
  
Impossible to convert between the formats supported by the filter 'graph 0 input from stream 0:0' and the filter 'auto_scaler_0'
Error reinitializing filters!


  


  The same command without CUDA works, ie

  


  ffmpeg -y -ss 1 -i "FILE0001.MOV" -ss 0 -i "GOPR0621.MP4" -filter_complex 
[0:v][1:v]
  midequalizer
[al];
[al]
  yadif
  lenscorrection
  scale
[vl];
[1:v]
  lenscorrection
  scale
[vr];
[vl][vr]
  hstack=shortest=1 
-an "output.mp4"


  


  How do I make it work on a Windows 10 machine with cuda ?

  


• How to use ffmpeg to merge multiple .mp4 files ? (same encoder, simple merge will work)

  6 août 2019, par Mars Robertson

  I’m trying :

  • How to concatenate two MP4 files using FFmpeg ?
  • https://superuser.com/questions/1059245/ffmpeg-join-two-mp4-files-with-ffmpeg-on-command-line

  ---

  Option A :

  ffmpeg -f concat -i list.txt -c copy output

  Line 1 : unknown keyword ’file’
  list.txt : Invalid data found when processing input

  cat list.txt
file './001-eclipse.mp4'
file './002-sundown.mp4'
file './003-robothear.mp4'
file './004-NOPE-boring-tower.mp4'

  Option B :

  ffmpeg -i "concat:001-eclipse.mp4|002-sundown.mp4|003-robothear.mp4|004-NOPE-boring-tower.mp4" -c copy output.mp4

  ffmpeg version 4.0.2 Copyright (c) 2000-2018 the FFmpeg developers
 built with Apple LLVM version 9.1.0 (clang-902.0.39.2)
 configuration: --prefix=/usr/local/Cellar/ffmpeg/4.0.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
 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
 libavresample   4.  0.  0 /  4.  0.  0
 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 @ 0x7feb1d001200] Found duplicated MOOV Atom. Skipped it
   Last message repeated 2 times
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'concat:001-eclipse.mp4|002-sundown.mp4|003-robothear.mp4|004-NOPE-boring-tower.mp4':
 Metadata:
   encoder         : Lavf58.12.100
   major_brand     : isom
   minor_version   : 512
   compatible_brands: isomiso2avc1mp41
 Duration: 00:00:13.64, start: 0.000000, bitrate: 161885 kb/s
   Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 5376x2688, 54015 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
   Metadata:
     handler_name    : VideoHandler
Output #0, mp4, to 'output.mp4':
 Metadata:
   compatible_brands: isomiso2avc1mp41
   major_brand     : isom
   minor_version   : 512
   encoder         : Lavf58.12.100
   Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 5376x2688, q=2-31, 54015 kb/s, 25 fps, 25 tbr, 12800 tbn, 12800 tbc (default)
   Metadata:
     handler_name    : VideoHandler
Stream mapping:
 Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame=  341 fps=0.0 q=-1.0 Lsize=   89943kB time=00:00:13.52 bitrate=54497.5kbits/s speed=90.2x
video:89937kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.005972%

  It contains only the first video :/

  ---

  Any ideas ?

  My version on Mac :

  ffmpeg -version
ffmpeg version 4.0.2 Copyright (c) 2000-2018 the FFmpeg developers
built with Apple LLVM version 9.1.0 (clang-902.0.39.2)
configuration: --prefix=/usr/local/Cellar/ffmpeg/4.0.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
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
libavresample   4.  0.  0 /  4.  0.  0
libswscale      5.  1.100 /  5.  1.100
libswresample   3.  1.100 /  3.  1.100
libpostproc    55.  1.100 / 55.  1.100