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• FFMPEG - stream download + resize + HVEC convert in one statement ?

  6 mars 2021, par Armitage2k

  I have a collection of 30 to 60 minutes PORTRAIT videos which I download via the below ffmpeg statement. That part works fine, but given that the resolution of the videos is quite high, it results in approx. 1,3 GB mp4 files.

  


  Once downloaded, I usually convert the video to 720p resolution which brings it down to approx. 500 MB per video, and then run another HVEC x265 compression which alas results in 250MB - 350MB sizes.

  


  Since its quite tedious to do all this manually, I was wondering if there is a FFMPEG statement / command I can use that achieves all of this in one go while downloading ?

  


  Below the commands I currently use.

  


  Thank you

  


  Download : ffmpeg -i http://somewebsite.com/path/to/playlist.m3u8 -c copy -bsf:a aac_adtstoasc L2_60min_vinyasa_vicky.mp4

  


  Convert : ffmpeg -i INPUT.mp4 -c:v libx265 -c:a copy -x265-params crf=25 OUTPUT.mkv

  


• calling ffmpeg from python in a loop

  22 juin 2018, par Steffen Lesch

  I am currently writing my first python script to split large audio files into smaller ones. (Splitting Albums into individual tracks) :

  import subprocess
  
  
  
  def genList():
  
      with open("commands.txt") as file:
  
          ffmpeg_template_str = 'ffmpeg -i audio.FLAC -acodec copy -ss START_TIME -to END_TIME LITTLE_FILE'
  
          lines = file.readlines()
  
          results = []
  
  
  
          for line in lines:
  
              argument_list = line.split(' ')
  
              result = ffmpeg_template_str
  
              results.append(result.replace('START_TIME', argument_list[0]).replace('END_TIME', argument_list[1]).replace('LITTLE_FILE', argument_list[2]))
  
      return results;
  
  
  
  def split():
  
      commands = genList()
  
      for command in commands:
  
          subprocess.call(command.split(' '))
  
  
  
  split()

  When i execute the script, many command line windows will pop up, but only the last delivers the desired result.

  So if i want to split an audio file into smaller files only the last split operation seems to executed correctly.

  Additionally if i dont use a for loop and just paste subprocess.call multiple times into the code it works just fine.

  subprocess.call(command1)
  
  subprocess.call(command2)
  
  subprocess.call(command3)

  Any help will be greatly appreciated.

• Revision b29c48b03c : Shorten GF/arf interval in hard scenes. This patch accounts in the first pass s

  6 mars 2015, par paulwilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_firstpass.c

  
  
  Shorten GF/arf interval in hard scenes.

  This patch accounts in the first pass stats for blocks that
  while not coded as intra, are complex and have an intra error /
  best error ratio below a threshold.

  The modification shortens the GF arf interval for a particular
  class of content that contains a lot of blocks matching the
  above criteria. (In one short problem test sequence the average
  interval dropped from about 14-15 to 10-11)

  The change results in small net gains in metrics results for the
  Yt( 0.2%) and yt-hd ( 0.5%) sets and is approximately neutral
  for the other test sets.

  The change is currently shielded by a flag and off by default
  pending verification that it does not cause other regressions
  in tests on a wider YT test set.

  Change-Id : I6b803daa6a4ac09a6f428fb3a18be1ecedd974b7