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• How do I resolve ffmpeg concat command error "unknown keyword..." ?

  6 décembre 2023, par Scorb

  I am trying to concatenate two video files using ffmpeg, and I am receiving an error.

  


  To eliminate compatibility issues between the two videos, I have been concatenating the same video with itself, and the same error persists.

  


  ffmpeg \
  -f concat \
  -safe 0 \
  -i intro_prepped.avi intro_prepped.avi \
  -c copy \
  concat.avi  


  


  And the error output I receive is....

  


  


  [concat @ 0x220d420] Line 1 : unknown keyword 'RIFFf� ?'
intro_prepped.avi : Invalid data found when processing input

  


  


  I have tried various combinations of concat flags and have not been able to get it to work. Has anyone seen this error before ?

  


• How to preserve colours when colour metadata is "unknown"

  5 avril 2024, par Hashim Aziz

  I often need to scale up many files with unknown color metadata (probably because FFmpeg itself was dropping that metadata until very recently) :

  


  $ ffprobe -v error -show_streams "input.mp4" | grep color

color_range=tv
color_space=unknown
color_transfer=unknown
color_primaries=unknown


  


  No matter what I do to try and preserve the colours in these files, nothing works to prevent the colours from shifting, usually coming out darker than the input.

  


  I've already tried :

  


  


  1. Setting all four color metadata options (-colorspace, -color_trc, -color_primaries, -color_range) to all of their possible values for PAL, NTSC and HD inputs (bt470bg, smpte170m and bt709 respectively)

     


  


  2. Automatically converting the colorspace as part of the scale by adding in_color_matrix=auto:out_color_matrix=<colorspace></colorspace>, where is either bt470, smpte170m or bt709

     


  


  3. Explicitly converting the colorspace as part of the scale by adding in_color_matrix=<colorspace>:out_color_matrix=bt709</colorspace>, where is either bt470, smpte170m or bt709

     


  


  


  After all of this, I'm still left none the wiser as to how the hell colour works in FFmpeg and what I'm meant to be doing just to get my colour to look as it does in the original input.

  


  Here is the (simplified) FFmpeg command that I'm running as part of a larger script, most of which is probably irrelevant to the issue but which I've included in case it isn't :

  


  ffmpeg -y -hide_banner \
-i "input.webm" -i "outro.mp4" -loop 1 -i "watermark.png" \
-movflags +faststart+write_colr \ 
-filter_complex \
"color=black:16x16:d=780[base];
[0:v]scale=1922:'max(1080,ih)':flags=lanczos:in_color_matrix=auto:out_color_matrix=bt709[v0];
[1:v]scale=1922:'max(1080,ih)':flags=lanczos,fade=in:st=0:d=2:alpha=1[v1];
[2:v]lut=a=val*0.7,fade=in:st=15:d=3:alpha=1,fade=out:st=775:d=3:alpha=1[v2];
[base][v0]scale2ref[base][v0];
[base][v0]overlay[tmp];
[tmp][v1]overlay,setsar=1[tmp2];
[v2][tmp2]scale2ref=w=oh*mdar:h=ih*0.07[watermark_scaled][video]
[video][watermark_scaled]overlay=80:50:shortest=1:format=rgb[outv];
[0:a]afade=out:st=778:d=2[0a];
[0a][1:a]concat=n=2:v=0:a=1[outa]" \
-map "[outv]" -map "[outa]" -c:v libx264 -crf 15 -c:a libopus \
-pix_fmt yuv420p -colorspace bt709 -color_trc bt709 -color_primaries bt709 -color_range tv "output.mp4" 


  


• Channel layout is unknown error, how to use filters with any number of channels ?

  8 novembre 2022, par Arthur Martens

  Using this command line

  


  'C:/Program Files/ffmpeg/bin/ffmpeg.exe' -i "INPUT.mxf" -map 0:0 -af atrim=start_sample=336000:end_sample=2448000,silencedetect=mono=1 -f null -

  


  I get the following error :

  


      Stream #0:0: Audio: pcm_s24le, 48000 Hz, 12 channels, s32 (24 bit), 13824 kb/s
    Metadata:
      file_package_umid: 0x060A2B340101010501010F2013000000D8A84B5D697B45F6ABAD7B54C1D78390
      file_package_name: File Package: SMPTE 382M frame wrapping of wave audio
      track_name      : Sound Track
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s24le (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
[auto_resampler_0 @ 000002449bdf03c0] Cannot select channel layout for the link between filters auto_resampler_0 and Parsed_silencedetect_1.
[auto_resampler_0 @ 000002449bdf03c0] Unknown channel layouts not supported, try specifying a channel layout using 'aformat=channel_layouts=something'.
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0
Conversion failed!


  


  How can I use filters, like scan a 12 channel input for silence, when there is no channel layout ?