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• Multiple resolutions for HLS transcoding using FFMPEG in Node Js

  11 janvier 2023, par Ammar Abdul Aziz

  I working on a node js project to convert uploaded mp4 files to HLS format (.m3u8) using FFMPEG.

  


  I've developed a function like this,

  


  


  


  ffmpeg('test.mp4', { timeout: 432000 })
  .addOptions([
      "-profile:v baseline",
      "-level 3.0",
      "-start_number 0",
      "-hls_time 10",
      "-hls_list_size 0",
      "-master_pl_name master.m3u8",
      "-f hls"
  ])
  .output("videos/output.m3u8")

  


  


  



  Question : This function is working as expected. But now I want the video to be transcoded in multiple formats in 360, 480, 720 and 1080 and expect an output of .m3u8 master file somewhat like

  


  


  


  #EXTM3U
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=72000,CODECS="mp4a.40.5"
output_64k_audio.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=620000,RESOLUTION=640x360,CODECS="avc1.4d001e,mp4a.40.2"
output_360.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=812000,RESOLUTION=854x480,CODECS="avc1.4d001e,mp4a.40.2"
output_480.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1272000,RESOLUTION=1280x720,CODECS="avc1.4d001f,mp4a.40.2"
output_720.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1627000,RESOLUTION=1920x1080,CODECS="avc1.4d0028,mp4a.40.2"
output_1080.m3u8

  


  


  



  Please help me with a solution to this.

  


• Issues with ffmpeg image options

  5 janvier 2023, par Aenye_Cerbin

  I've some issues with combining multiple image options in ffmpeg.
My sample command with all options I want to change :

  


  ffmpeg -y -i sample.jpg -qscale:v 2 -pix_fmt rgb24 -vf scale=640:480 eq=brightness=0.5:contrast=0.5:saturation=0.5 -f png output.png


  


  I've several issues with this command and have been trying to rewrite it for a while, here is what I found :

  


  

  1. after -vf I cannot specify both scale and eq, if I use only one it will work.

  


  2. I cannot for some reason use -f png option.

  


  


  For 1. I got such results (for both removed -f png option) :

  


  

  • If I have both scale and eq :
    [NULL @ 0000024581fd1a80] Unable to find a suitable output format for 'eq=brightness=0.5:contrast=0.5:saturation=0.5' eq=brightness=0.5:contrast=0.5:saturation=0.5: Invalid argument

  


  • If I remove scale or eq it works

  


  


  Is there any way to combine scale with options such as brightness and contrast. If I want to add another effects such as : colorchannelmixer how to add it ?

  


  Why am I getting this error with -f png option, how can I specify the format ?

  


• 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