[FFmpeg-devel] [PATCH] Dolby Digital dynamic range compression (drc_scale) is now 0 by default

Nicolas George george at nsup.org
Mon Mar 30 13:35:42 CEST 2015

Le decadi 10 germinal, an CCXXIII, madshi a écrit :
> What do you think would happen if we started a vote like the following:
> 1) Should ffmpeg output reduced (range compressed) audio quality by
> default, because the spec says so?
> 2) Should ffmpeg output full (range) quality by default, unless the
> software asks ffmpeg to do otherwise?
> How many users or devs would vote for 1) or 2)?

Kieran will answer you "the spec is right even if it tells you that 2+2=5".

My answer is: profile, don't speculate.

Q: "the user has quality audio equipment that can play full range"
K: "the user knows that there is an option"
D: quantified damage to the sound (subjective impression translated to an
   approximate value)
d1: quantified damage of playing compressed range on quality equipment
d2: quantified damage of playing full range on poor equipment
d3: quantified damage of having to set an option

E(D) = P(K)×d3 + P(¬K∧Q)×d1 if compression is the default
E(D) = P(K)×d3 + P(¬K∧¬Q)×d2 is compression is disabled by default.

So basically, you need to provide convincing estimates for the ratio between
P(¬K∧Q) and P(¬K∧¬Q) and the one between d1 and d2.


  Nicolas George
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