[vdr] Channel specific volume (was: Re: remember volume)

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Marcus Kuba wrote:
> 
> Am 19.09.2001 19:46:00, schrieb Clemens Kirchgatterer <clemens@root.at>:
> 
> >> volume-stuff is of course an optical feedback... say a graph/number
> >> when changing the volume (and maybe in the channel-info-
> >> display) and some text/sign while mute is on.
> >
> >as we speak about volume wishes - what i miss since the first day i use
> >vdr is a default volume for each channel, cause they are broadcasted in
> >different loudness. especially mtv stands out. :-(
> 
> Well... I think I know Klaus' answer :-)
> 
> As long as there was no volume-control at all, such a setting made not much sense, now that volume-control is implemented, it would make. But then there is only one
> logical place to store that.. and we all should know what Klaus thinks about more fields in channels.conf...
> And even if there was such a parameter.. there is still some point to put on top: on channels with multiple audio-pids (e.g. Cinedom) there are also differences between
> the german/original version of the sound, so this value would have to be audio-pid-specific :-)
> Well Klaus.. what sign will you choose to reflect that... ";" and "," are already in use.. maybe "-"? :-)
> 
> Greetings,  Marcus

Do I hear (well, read) a slight sarcarsm in there?!
You almost sound as if you would have preferred separate fields for each audio PID
in channels.conf. I find nothing wrong with having _one_ field for the audio settings,
separated into "normal" and Dolby Digital by ';' and further separating different
languages by ','.

So, now that there seems to be such a big need for setting the volume of each channel
(or, better, each PID) separately, the logical conclusion is to add such a volume
setting to each audio PID (well, the "normal" audio PIDs, that is - I don't think
it makes sense with the Dolby Digital PIDs). Using '-' wouldn't be wrong, since none
of these values can get negative.

But let's sit back and think for a moment, before quickly hacking something together
without considering the implications.

A PID specific volume setting in channels.conf can, of course, only be a value
that is pretty much "constant", like, for instance, the PID itself. Once a channel
is known to broadcast louder than others, it gets assigned a volume value (less than 255)
to adjust it to the others.

The first thing we would need to find out here is: which channel (or PID) has the
lowest volume? That channel (and any other channel transmitting the same low volume)
would implicitly be assigned the maximum volume limit 255 (which I suggest need not be
explicitly given, so that those who don't mind the different volume levels are not
bothered), because that is the highest possible volume setting in the driver, and we
don't want to make the lowest volume even lower.

Any other channel that is louder can be assigned a maximum volume limit smaller
than 255, thus levelling all channels (PIDs) to roughly the same volume.

Now, how does the manual volume control fit in here? Logically if the user switches
to some channel and turns down the volume because he wants to answer the phone or
whatever, he will not want that change to go into the channels.conf. Plus, if he
adjusts the general ("master") volume, he will expect all channels to follow this
lead equally.

So, the bottom line is:

We will have the maximum channel (PID) volume value C and the master volume
value M (both can range from 0...255). The final actual volume setting will then
result to (M / 255) * C.

And: yes, of course VDR will store the master volume in setup.conf. I just didn't
have time to finish this last sunday...

Klaus
-- 
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Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
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