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

madshi madshi at gmail.com
Sun Mar 29 20:20:21 CEST 2015

2015-03-29 20:06 GMT+02:00 Kieran Kunhya <kierank at obe.tv>:
> > On 29 March 2015 at 18:01, Wiebe Cazemier <wiebe at halfgaar.net> wrote:
> > Signed-off-by: Wiebe Cazemier <wiebe at halfgaar.net>
> Why can't you just set this in your application?
> Not everyone is listening on a full setup where they can hear the dynamic

There are 2 possible situations:

1) Either the software using ffmpeg is aware of the "drc_scale" option. If
that is the case, the software is likely to set the option to the desired
value. So in this case it doesn't matter which value we set the default to.

2) Or the software using ffmpeg is not aware of the "drc_scale" option. In
this case currently ffmpeg defaults to applying range compression, which
severely damages audio quality. Which is a very bad idea.

So basically this patch tells ffmpeg to produce full decoding quality,
unless it's asked to do otherwise. Which is the only sane setup, IMHO.

If you think that range compression should be turned on by default, then we
should patch all other decoders to also do that by default. Why only AC3?
Makes no sense.

Best regards, Mathias.

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