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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.

• How to use ffmpeg to encode mp4 to mov

  19 avril 2017, par user1526912

  I trying to use ffmpeg to encode a video for the first time. Can anyone tell me the exact command to encode a video in the following format :

  Music Video HD Source Profile

  ● Apple ProRes 422 (HQ)
  ● VBR expected at 220 Mbps
  ● HD encoded dimensions accepted to support square pixel aspect ratios (PASP) :
  Encoded PASP Converted to ProRes From
  1920 x 1080 1:1 HDCAM SR, D5, ATSC
  1280 x 720 1:1 ATSC progressive

  ● HD encoded dimensions accepted to support non-square pixel aspect ratios (this allows you to send HD video in the native dimensions of your best original source, for example in HD broadcast dimensions*) :

  Encoded PASP Converted to ProRes From
  1440 x 1080 1:1.33333 XDCAM-HD, HDCAM
  1280 x 1080 1:1.5 DVCProHD interlaced
  960 x 720 1:1.33333 DVCProHD progressive

  Native frame rate of original source :

  ● 29.97 interlaced frames per second for video sourced
  ● 24 or 25 progressive frames per second for film sourced
  ● 23.976 progressive frames for inverse telecine sourced from film
  ● Telecine materials will not be accepted

  ● HD source may be delivered matted : letterbox, pillarbox, or windowbox.

  Music Video Audio Source Profile

  Stereo
  ● MPEG-1 layer II stereo
  ● 384 kpbs
  ● 48Khz
  ● Included in the same file as the delivered video

• Extracting media duration in R

  27 septembre 2015, par Jason French

  I’m investigating the fastest way to extract film duration in R using ffprobe and the data.table package.

  Setup Example Source Media

  wget https://ia801403.us.archive.org/13/items/AboutBan1935/AboutBan1935_512kb.mp4
  
  mv AboutBan1935_512kb.mp4 one.mp4
  
  for file in two.mp4 three.mp4 four.mp4 five.mp4 ; do cp one.mp4 "$file" ; done

  Various Approaches

  library(data.table)
  
  library(parallel)
  
  
  
  # Get locations
  
  executables <- Sys.which(c('ffprobe', 'ffmpeg'))
  
  
  
  # Duration Function
  
  get_duration_parallel <- function(files){
  
    mclapply(X = files, FUN = function(file){
  
      ffprobe_duration <- paste(executables['ffprobe'],
  
                                " -v quiet -print_format compact=print_section=0:nokey=1:escape=csv -show_entries format=duration ",
  
                                '"', file, '"', sep = "")
  
  
  
      file_duration <- as.numeric(system(command = ffprobe_duration, intern = TRUE))
  
      return(file_duration)
  
    }, mc.cores = detectCores())
  
  }
  
  
  
  get_duration <- function(files){
  
    sapply(X = files, FUN = function(file){
  
      ffprobe_duration <- paste(executables['ffprobe'],
  
                                " -v quiet -print_format compact=print_section=0:nokey=1:escape=csv -show_entries format=duration ",
  
                                '"', file, '"', sep = "")
  
  
  
      file_duration <- as.numeric(system(command = ffprobe_duration, intern = TRUE))
  
      return(file_duration)
  
    })
  
  }
  
  
  
  # Example table
  
  dt <- data.table(Path = list.files(path = ".", pattern = "*.mp4$"))
  
  
  
  
  
  system.time(
  
    dt[, Seconds := get_duration_parallel(Path)]
  
  )
  
  # 9.667 seconds    
  
  
  
  system.time(
  
    dt[, Seconds := get_duration(Path)]
  
  )
  
  # 0.078 seconds

  Am I missing any obvious speed-ups ? Scanning a 500-file archive for ffprobe stats takes 5 minutes in testing.