[matroska-general] Re: =[SPAM?]= Re: Dynamic Range Management
pfk at fuchs.offl.uni-jena.de
Sun May 25 20:39:56 CEST 2003
On Sun, May 25, 2003 at 04:31:48PM +0200, Steve Lhomme wrote:
> > Question
> > ~~~~~~~~
> > What do you think about this idea ?
> > Should this be part of Matroska or part of SV8 ?
> It depends if it's a codec specific thing, or it can be applied to any
> codec. In the latter case, I suggest to put it in Matroska. We already
> have ReplayGain informations (album and track). And we can add this to
> any audio block "properties" (saved in the BlockGroup, even better in
> the TimeSlice).
The Dynamic Changes are not specific to an audio block.
A new setting can be choosen after 64, 256, 1024 or 4096 samples and this
new value is applied smoothly between the two props.
> The problem is that it would be more convenient for the
> decoder to have the value for each "frame" and not just when it changes.
> Otherwise when you cut or seek in the file, you will lose that information.
> BTW, I'm thinking about when to apply it on decoding. It should be after
> decoding to PCM,
Dolby Digital applies it to the MDCT coefficients. Side effect is that so
the DRC is applied smoothly.
> so either in the Codec (ie this is codec specific, not
> supported by all possible codec in matroska) or hacking the output of
> the codec (dirty hack in DirectShow, it may be easier in MPlayer). So a
> codec specific system would be easier on the matroska side ;)
> But that's a feature that could be worth adding. To make all codec equal on this
> side :)
Known. Guess why I'm asking ...
> And let the codec really deal with coding data. But I'm not sure
> it will be the case on encoding, as only the codec can know how to
> manipulate data to make compression better.
The task is not to compress(1) the signal to make it easier to compress(2),
but to allow a playback in a noisy enviroment or in the late evening.
Or to apply a fade in and fade out after encoding of the signal.
> > Generic forms:
> > - up to 32 profiles
> > - volume can be changed static and dynamic
> > - can be used like DRC and Compression
> > - can be used for album replaygain
> > - can be used for title replaygain (with additional transition
> > between titles, to avoid clicks)
> Good idea. Even though it will need support in the authoring app (not
> muxing app).
- decoder do it automatically
- you have a function
- to get number of channels
- to select the channel
- editing/manupulation tools are SV8 related
- range management is done by the matroska framework
- usable for all audio file formats
- editing/manupulation tools are MATROSKA related
- dynamic range stream can have names ...
- more fexible I think
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