Re: [Bug-gnupod] mktunes --volume

[H. Langos]

Hi eric,

lets cover some basic things first. 

- have you checked how the files sound in a player on your machine? could it
  be that they are indeed too loud? 

- which version of gnupod are you using?

- which ipod model are you using?

- do you use any kind of software to organize your music files? (winamp,
  armarok, banshee ... )? does it have a plugin/option that could screw 
  up the volume?

- did you see that behaviour right from the start or did it only 
  occurre after some component was updated?

- do you use the ipod headphones (dont laugh, i recenty switched to the Koss
  "spark plugs" and they sound way louder than the original ipod headphones. )

- do you see the behaviour with every type of file (audio, video, different
  formats?
  

there are tools that "normalize" the volume across several files without 
re-encoding, simply by screwing with the scaling factors that are the basis 
of frequency based encoding schemas. 

could you send me one of the files?

the order in which you do things looks perfectly ok to me. 

did you try to set volume out of its range ( e.g. -105 )just to see if mktunes
complains?

I took a look at the code that translates the volume when creating the
iTunesdb file:

        #We have to fix 'volume'
        my $vol = sprintf("%.0f",( int($file_hash{volume})*2.55 ));
        if($vol >= 0 && $vol <= 255) { } #Nothing to do
        elsif($vol < 0 && $vol >= -255) {            #Convert value
                $vol = ((0xFFFFFFFF) + $vol);
        }
        else {  
                warn "** Warning: ID $file_hash{id} has volume set to 
$file_hash{volume} percent. Volume set to +-0%\n";
                $vol = 0; #We won't nuke the iPod with an ultra high volume 
setting..
        }

as i read it, this code assumes that $vol is a 32 bit integer. i am not sure
if that is the case on 64 bit machines. 

@adrian? any experience there?

i havn't tried a negative soundcheck value yet. I don't think it would work.
i've never encountered an iTunNORM comment that contained negative scaling
factors. 

cheers
-henrik


On Fri, Jan 23, 2009 at 10:06:21PM -0500, eric himmelreich wrote:
> Henrik,
> 
> Thanks for your suggestion, but I'm still not getting any results.
> 
> I checked in GNUtunesDB.xml, soundcheck="" for all the songs.. so that looks
> like its not the culprit, and volume="" for all settings.  I tried setting
> volume="50", volume="0", volume="-50" for all songs (regex replace in vim).
> Then I did mktunes.pl -m /mnt/ipod/, and ejected the drive.  The volume
> isn't any different.  Any ideas?  Am I doing this in the right order (edit
> GNUtunesDB.xml, then mktunes and eject)  also how does soundcheck work?  Can
> I use a negative scaling factor? ie make all songs a little quieter?
> 
> -Eric
> 
> On Fri, Jan 23, 2009 at 9:38 PM, H. Langos <address@hidden> wrote:
> 
> > hi eric,
> >
> > On Fri, Jan 23, 2009 at 11:36:13AM -0500, eric himmelreich wrote:
> > > Here is the situation..  I load up my ipod using gnupod_addsong, do
> > mktunes
> > > and eject it.  Its ready for listening.
> > > The problem, the volume is too loud (even when I turn the volume down on
> > the
> > > ipod all the way).
> > >
> > > Isn't there some kind of internal volume setting that I can adjust?
> > >
> > > I've tried using mktunes --volume -50, but it doesn't seem to work.  I
> > want
> > > to check what the volume is set at now, and to lower it a lot.
> >
> > as i see it there are two attributes in your GNUtunesDB.xml that coud
> > influence
> > the volume of a song on the ipod. one would be "volume" and "soundcheck"
> > the other.
> >
> > i don't know how the volume attribute influences the ipod's volume so
> > here's
> > how you could test if soundcheck is the trouble maker.
> >
> > soundckeck is influenced by the data that gnupod reads from meta data that
> > iTunes and other software leave in the mp3 tags. (iTunesNORM is the name of
> > that comment)
> >
> > if gnupod doesn't find any comment that looks like the iTunesNORM data, it
> > will leave put soundcheck="0" in your GNUtunesDB.xml otherwise it will put
> > a
> > scaling factor in there that is used to normalize the volume across
> > different songs.
> >
> > please let me know if you need help to find the GNUtunesDB.xml or a fast
> > way
> > to look for non-zero soundcheck attributes there.
> >
> > cheers
> > -henrik
> >
> >