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• avfilter/af_afftdn : stop producing small impulsive noise at start of output

  14 mars 2022, par Paul B Mahol

  avfilter/af_afftdn : stop producing small impulsive noise at start of output
  

  • [DH] libavfilter/af_afftdn.c

• random_seed : Improve behaviour with small timer increments with high precision timers

  29 janvier, par Martin Storsjö

  random_seed : Improve behaviour with small timer increments with high precision timers
  On a Zen 5, on Ubuntu 24.04 (with CLOCKS_PER_SEC 1000000), the
  
  value of clock() in this loop increments by 0 most of the time,
  
  and when it does increment, it usually increments by 1 compared
  
  to the previous round.
  Due to the "last_t + 2*last_td + (CLOCKS_PER_SEC > 1000) >= t"
  
  expression, we only manage to take one step forward in this loop
  
  (incrementing i) if clock() increments by 2, while it incremented
  
  by 0 in the previous iteration (last_td).
  This is similar to the change done in
  
  c4152fc42e480c41efb7f761b1bbe5f0bc43d5bc, to speed it up on
  
  systems with very small CLOCKS_PER_SEC. However in this case,
  
  CLOCKS_PER_SEC is still very large, but the machine is fast enough
  
  to hit every clock increment repeatedly.
  For this case, use the number of repetitions of each timer value
  
  as entropy source ; require a change in the number of repetitions
  
  in order to proceed to the next buffer index.
  This helps the fate-random-seed test to actually terminate within
  
  a reasonable time on such a system (where it previously could hang,
  
  running for many minutes).
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavutil/random_seed.c

• Ffmpeg & PHP - Small Clip with Good Quality

  14 novembre 2013, par FakeHeal

  what are the best options to keep video in nearly good quality while converting it to flv and shrinking its size ?

  I use the followin code now :

  exec("ffmpeg -i $faila -sameq -s 600x450  -ar 44100 $file_final");