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• 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/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

• Ffmpeg cpp libav randomly uses high cpu and less gpu or uses high gpu and less cpu with hw accel

  29 avril 2024, par cngkyt

  I am using ffmpeg as library with cpp
the integration of library is perfectly done i am using AVFilterGraph as audio resampler and video pixfmt converter.

  


  I cannot share code because it is a complete library and contains too many files but i can assure there is no problem about code but maybe approach.

  


  My whole class is based on the transcode example of ffmpeg
text

  


  The problem is when i run my program that encodes approx 90 streams

  


  it starts with 25% cpu usage 80% gpu encode usage %85 gpu decode usage with 100% sm utilization

  


  or

  


  it starts with 80% cpu usage 45% gpu encode usage 50% gpu decode usage with 60% sm utilization

  


  when it start like second type of utilization videos are perfect
but when it starts like the first type of utilization videos are freezing

  


  my program uses pure gpu for encoding for all streams but using gpu decoding for every 3 cpu deoding
that means i use hwaccel for 1/3 of streams
because my cards are 4070 ti super and they have 2 NVENC 1 NVDEC chips

  


  my program takes udp streams and encode it and outputs udp mpegts

  


  bitrate and quality settings are persistent across streams depending on resolution

  


  i always test on same streams

  


  the problem happens randomly
but if it starts with high cpu and low gpu utilization it goes on like this
when i restart program problem occurs randomly again

  


  what can couse this

  


  just as an info i have experience on c++ more than 25 years

  


  if there is someone who can teach me something i will be happy

  


  thanks for your further helps

  


  i have tried to reproduce it with compiled ffmpeg instead of my libav library usage
same thing happens but not often

  


  i have tried using hevc_cuvid instead of hwacceleration with avcodec_find_decoder_by_name function