[FFmpeg-devel] [PATCH] AC3 volume options

Michael Niedermayer michaelni
Sun Dec 16 14:59:03 CET 2007


On Sat, Dec 15, 2007 at 08:52:41PM -0500, Justin Ruggles wrote:
> Hi,
>
> AC3, E-AC3, DTS, TrueHD all have dynamic range compression and dialog 
> normalization capability.  Right now the AC3 decoder is the only one which 
> uses them, and it applies them by default.
>
> This patch disables them by default, but adds the options to allow the user 
> to activate them if wanted.
>
> The dialog normalization option is used for both encoding and decoding.  
> For the decoder, it just turns it on or off.  For the encoder, the value is 
> used in the output stream.

1. decoders should export the dynamic range & dialog norm
2. encoders should use the values form 1. and of course end with the same
   loudness
   -> this also means externally vissible values must be format independant

3. the AC3 spec specifies clearly what are the mandatory defaults, why
   do you disregard that?
4. the spec says:
"It is also permissible (again under listener control) for the decoder to use some
 fraction of the dynrng control value, and to use a different fraction of positive or negative values."
why dont you do this and instead suggest a vastly inferrior switch on/off?!

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you really think that XML is the answer, then you definitly missunderstood
the question -- Attila Kinali
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