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• A ffmpeg h.265 hardware issue

  27 août 2015, par R.P. da Costa

  Hi i have a ffmpeg hardware related problem.
  Simply put : The conversion works on mac, but on some TV screens the converted h.265 video will give a few seconds of delay when it starts playing !

  A response will be much appreciated !

  Input :

  UHD(3840x2160) Prores 422(HQ) master file

  What we used to recompile to a 16bit renderer :

  brew uninstall ffmpeg
  
  brew uninstall x265
  
  brew uninstall --force x265
  
  brew install x265 --16-bit
  
  brew install ffmpeg --with-fdk-aac --with-ffplay --with-freetype --with-libass --with-libquvi --with-libvorbis --with-libvpx --with-opus --with-x265

  Code we used in FFMpeg :

  -b:v 36000k -maxrate 38000k -c:v libx265 -pix_fmt yuv420p10le -x265-params "profile=main10:level=5.1:b=36000k" -c:a aac -strict experimental -b:a 256k

  Preferred Output

  3840x2160 resolution
  
  10bit 4:2:0  colordepth
  
  Main 10@L5.1@High format profile
  
  MP4 container
  
  HEVC codec
  
  24p framerate
  
  38Mb Variable bitrate
  
  256Kb Variable bitrate/AAC audio

  Output device is Tarakan UHD Stream Generator T7

  Our problem :

  The encode file that FFmpeg gives is correct, on spec level.
  I would like the file to have a Main 10 High level 5.1 format profile.
  Based on the specs I’ve put into FFmpeg, it automatically makes a file with a level 5.0 profile, as it doesn’t need a higher level based on the specs.

  The file plays correctly on a Mac.
  The file must also play correctly on a Tarakan UHD Stream Generator(media player with multiple HDMI outputs). The file takes a while to load, chops off 5-6 seconds of the beginning of the film, then plays correctly.

• ffmpeg transcode ONLY if downsampling

  22 avril 2020, par Shurov

  I'm using Airsonic as a home music server. It has ffmpeg transcoding capabilities. I'd like to transcode audio ONLY IF input stream has higher parameters (any of kb/s, bit, kHz). And leave native quality if file has lower params (so not to UPscale). Is it possible using some of the ffmpeg options ?

  



  P.S. Airsonic has some Downsample field, but it doesn't seem to work at all.

  


• FFMPEG Encoding MP4 for iOS

  3 août 2015, par Ryan K

  I am using the gem streamio-ffmpeg to convert an .mp4 file to another .mp4 file that conforms to iOS standards. I want to put that file in an HTML5 video tag. The video plays well on desktop and Android devices. However, no matter what I do, the iPad Mini 2 that I’m using will not play the video.

  My options hash looks like this :

  options = {video_codec: "libx264", resolution: "480x320", frame_rate: 30, video_bitrate: 500,
  
               x264_vprofile: "baseline", x264_preset: "slow", audio_codec: "aac", audio_bitrate: 56, aspect: 1.333333,
  
               audio_sample_rate: 44100, audio_channels: 1, custom: "-strict -2"}

  When I load the new .mp4 file back into streamio-ffmpeg, this is the object (and metadata) returned :

  #

  I’ve tried just about everything I could find, with different bit rates, codecs, resolutions, etc. What are the correct options to play an .mp4 on an iOS device ?

  BTW, streamio-ffmpeg allows pure ffmpeg options, so I’m ok with that.