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• ffmpeg/libav easy way to set options

  13 mars 2023, par Patrick

  I recently messed around with ffplay code to see how it works and I noticed it uses a very straight forward way to parse and set all the command line options using the library internal cmdutils.h. I personally find the av_opt_set used in other examples of av wrappers quite confusing (Some args are explicitly stored in the struct, some in priv_data ? Im allowed/supposed to modify void*priv_data ? Which objects can I use av_opt_set on ? Which args go in which object and are they declared or in priv_data ? Where is this documented ?).
In ffplay all args are simply stored in an array and distributed to the right codec/muxer/format instance using cmdutil.
Id like to have exactly this functionality for my program (so that i can simply read a json config and don't need to care about it any further). Apparently the necessary OptionDef arrays are already defined in different implementation files.

  


  However my actual question : I noticed the OptionDef array definition in ffplay does not contain all options (only some from cmdutil included via macro). But other options e.g. fflags are not included anywhere (only defined somewhere else) and yet they work. So how does cmdutil set/parse them ?

  


  I hope someone can answer this, since simply adapting cmdutil would be a quite simple solution for me. Id also really appreciate some general guidance regarding my previous questions.

  


  Many Thanks in advance !

  


  I tried looking into the ffmpeg source and expected all OptionDef array definitions to be connected/collected inside a single array such that cmdutil can parse them easily. However this isn't the case and still some cmd options work. Therefore Im confused on how cmtutil is able to parse them

  


• ffmpeg/libav easy way to set options for muxer, codec, format, etc [closed]

  14 mars 2023, par Patrick

  Edit (shorter question) :

  


  In the ff tools (e.g. ffplay) I can set all kinds of options by simply providing a list of arguments in cmd. Id like to do that programmatically as well and without having to look up where it belongs and insert it in the different AVDictionary by hand every time. Is there a way to do this easily ?

  


  Long question :

  


  I recently messed around with ffplay code to see how it works and I noticed it uses a very straight forward way to parse and set all the command line options using the library internal cmdutils.h. I personally find the av_opt_set used in other examples of av wrappers quite confusing (Some args are explicitly stored in the struct, some in priv_data ? Im allowed/supposed to modify void*priv_data ? Which objects can I use av_opt_set on ? Which args go in which object and are they declared or in priv_data ? Where is this documented ?).
In ffplay all args are simply stored in an array and distributed to the right codec/muxer/format instance using cmdutil.
Id like to have exactly this functionality for my program (so that i can simply read a json config and don't need to care about it any further). Apparently the necessary OptionDef arrays are already defined in different implementation files.

  


  However my actual question : I noticed the OptionDef array definition in ffplay does not contain all options (only some from cmdutil included via macro). But other options e.g. fflags are not included anywhere (only defined somewhere else) and yet they work. So how does cmdutil set/parse them ?

  


  I hope someone can answer this, since simply adapting cmdutil would be a quite simple solution for me. Id also really appreciate some general guidance regarding my previous questions.

  


  Many Thanks in advance !

  


  I tried looking into the ffmpeg source and expected all OptionDef array definitions to be connected/collected inside a single array such that cmdutil can parse them easily. However this isn't the case and still some cmd options work. Therefore Im confused on how cmtutil is able to parse them

  


• ffmpeg custom compile options with hardware/software support

  14 mars 2023, par Capitalmind

  My last compile enabled nvidia/cuda but even though I included —enable-nonfree in the configure, I had issues encoding videos, with outputs like :

  


  ffmpeg -hwaccel cuvid -c:v h264_cuvid -resize 1920x1080 -i Input.mkv -c:a copy -c:v h264_nvenc -preset slow -rc vbr_hq -cq 18 Output.mkv

  


  Giving errors like :

  


  ffmpeg -hwaccel cuvid -c:v h264_cuvid -resize 1920x1080 -i /media/zuultux/Video/Movies/Lawrence.of.Arabia.1962.UHD.BluRay.2160p.TrueHD.Atmos.7.1.HEVC.mkv -c:a copy -c:v h264_nvenc -preset slow -rc vbr_hq -cq 18 /media/zuultux/Video/Lawrence.of.Arabia.1962.UHD.BluRay.1080p.TrueHD.Atmos.7.1.HEVC.mkv


  


  [hevc_cuvid @ 0x5624718179c0] Codec hevc_cuvid is not supported.
Stream mapping:
  Stream #0:0 -> #0:0 (hevc (hevc_cuvid) -> h264 (h264_nvenc))
  Stream #0:1 -> #0:1 (copy)


  


  My actual configure reads :

  


  ./configure --enable-nonfree --enable-cuda-nvcc --enable-libnpp --extra-cflags=-I/usr/local/cuda/include --extra-ldflags=-L/usr/local/cuda/lib64


  


  There a heaps of options on Githhub. Can anyone suggest how to include parameters that specifically :

  


  

  • Toggle enable AMD64/Nvidia or non-hardware processing

  


  • All free and non-free codecs, but particularly VC9, H264/265

  


  • Or basically enable as many features as possible !

  


  


  Note I already have ubuntu-restricted-extras installed.

  


  Configuration used compiled correctly but gave errors when using. Several media files selected to test. nvidia-smi command responds NVIDIA-SMI 470.161.03 Driver Version : 470.161.03 CUDA Version : 11.4

  


  ---

  


  Edit

  


  After fixing the problem I thought to share my results on Github. https://github.com/Capitalmind/makeffmpeg