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• avcodec/bsf/mp3_header_decompress : Remove BSF

  28 février 2024, par Andreas Rheinhardt

  avcodec/bsf/mp3_header_decompress : Remove BSF
  This BSF is supposed to be used in conjunction with mp3_header_compress,
  
  which has been removed more than ten years ago in commit
  
  c6080d89009056530119ab794ad02e4d515c7754. It mangled the headers
  
  by removing the CRC field as well as fields that are supposed
  
  to stay constant for the entirety of a stream (which are put into
  
  extradata). This made these files unplayable ; they need to be
  
  decompressed with the BSF first (which does not happen automatically).
  
  Even in this case the CRC does not get restored.
  I am not aware that such compressed files exist at all ; therefore
  
  this commit removes the BSF completely.
  Reviewed-by : Anton Khirnov <anton@khirnov.net>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] doc/bitstream_filters.texi
  • [DH] libavcodec/Makefile
  • [DH] libavcodec/bitstream_filters.c
  • [DH] libavcodec/bsf/Makefile
  • [DH] libavcodec/bsf/mp3_header_decompress.c
  • [DH] libavcodec/version.h

• Unable to find replacement for -vol [closed]

  21 février 2024, par Michael Benton

  I'm referring to this thread posted years ago.

  


  While I was testing Downmixing without discarding the LFE channel (Dave_750's answer) on ffmpeg, which included the formula

  


  ffmpeg -i "sourcetrack.dts" -c dca -vol 425 -af "pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3" "outputstereo.dts"


  


  the cmd raised the following error :

  


  Unrecognized option 'vol'. Error splitting the argument list: Option not found


  


  The formula I put in cmd wasn't the same as the one in the thread at the beginning, because I replaced in it the attributes of my ac3 track.

  


  ffmpeg -i "inputsurround.ac3" -vol 425 -af "pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3" -c:a ac3 -b:a 320k -ar 48000 "outputstereo.ac3"


  


  Through this thread, I discovered that the -vol function was deprecated years ago.

  


  I found another thread where the syntax used was

  


  -af volume=N


  


  (where N stands for a percentage or, if N is followed by "dB", a dB value).

  


  I'm not sure if -af volume behaves exactly like -vol while downmixing to stereo the ac3.

  


  I went back editing the formula :

  


  ffmpeg -i "inputsurround.ac3" -af "volume=425" -af "pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3" -c:a ac3 -b:a 320k -ar 48000 "outputstereo.ac3"


  


  It raised the following warning (which didn't stop the file generation) :

  


  Multiple -filter/-af/-vf options specified for stream 0, only the last option '-filter:a pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3' will be used


  


  As I already suspected, I couldn't use two "-af" in the same command. The generated file is useless, because ffmpeg only applied one of the two commands. I also tried with N defined in dB, with no success.

  


  I continued my search and, from another thread, I learned that I could use

  


  -filter_complex "[1] formula1;[0] formula2"


  


  to resolve my issue.

  


  My formula then became :

  


  ffmpeg -i "inputsurround.ac3" -filter_complex "[1]volume=425;[0]pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3" -c:a ac3 -b:a 320k -ar 48000 "outputstereo.ac3"


  


  And it still raised an error :

  


  Invalid file index 1 in filtergraph description [1]volume=425;[0]pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3.
Error initializing complex filters: Invalid argument


  


  To simplify the formula, I went back using -af with the properties of -filter_complex. And I got :

  


  ffmpeg -i "inputsurround.ac3" -af "[1]volume=425;[0]pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3" -c:a ac3 -b:a 320k -ar 48000 "outputstereo.ac3"


  


  Again, another error :

  


  Simple filtergraph '[1]volume=425;[0]pan=stereo|c0=0.5*c2+0.707*c0+0.707*c4+0.5*c3|c1=0.5*c2+0.707*c1+0.707*c5+0.5*c3' was expected to have exactly 1 input and 1 output. However, it had 2 input(s) and 2 output(s). Please adjust, or use a complex filtergraph (-filter_complex) instead.
[aost#0:0/ac3 @ 000001d83b4c4200] Error initializing a simple filtergraph
Error opening output file outputstereo.ac3.
Error opening output files: Invalid argument


  


  whether I used a semicolon or comma as a separator.

  


  I'm completely lost at this point as I don't have deep knowledge of the topic.

  


  


  • has -vol been deprecated or I've searched badly/it's a syntax typo ?

    


  


  • if -vol has been deprecated, is there a way to rewrite the formula such that it outputs the result intended by the original user ?

    


  


  • if I replace c0, c1, c2, c3, c4, c5 to FL, FR, FC, LF, BL, BR in the formula, would I get a different channel layout ? (my file is : L, R, C, LFE, Ls, Rs)

    


  


  


  I'll try to clear every doubt. Any help is highly appreciated !

  


• avcodec/libaomenc : bump the minimum required version to 2.0.0

  5 avril 2024, par James Almer

  avcodec/libaomenc : bump the minimum required version to 2.0.0
  v2.0.0 is already four years old and even newer versions are available on
  
  stable distro releases.
  
  With this we stop setting codec capabilities during static data initialization.
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] configure
  • [DH] libavcodec/libaomenc.c