Re: [Fwd: Re: [Bug-gnupod] SoundCheck/ReplayGain]

[Heinrich Langos]

Hi chris,

There have been some hardware issues at gnu.org. But as far as I heard the
mailing list hosts were not involved ... 
Let's see if this mails gets archived.

Could you send me a tar.gz of the ipod after adding those files with gnupod
and after having synched with itunes? 

Having the complete picture will help me to verify what exactly itunes does
to which file.

cheers
-henrik

On Thu, Jun 04, 2009 at 10:17:34PM +0200, chris.com wrote:
> Hello Henrik,
> It seems I can't get through to bug-gnupod. I've sent three messages  
> already, do you confirm there is a problem?
> Anyway here is the (non -archived) message:
>
> I managed to get some good results by replacing in  
> iTunesDB.pm::mk_itunes_sd_file:237, the line
>       $ret .= tnp(0x64-($ref->{volume}));
> with
>       $ret .= tnp($ref->{soundcheck));
> But I have to convert the SoundCheck value back to ReplayGain.
> I'm not in the mood for mathematics now but I'll look into it tomorrow  
> because this seems to work OK ;o)
>
> Bye for now
>       chriss
>
>
> -------- Original Message --------
> Subject: Re: [Bug-gnupod] SoundCheck/ReplayGain
> Date: Wed, 03 Jun 2009 20:41:08 +0200
> From: chris.com <address@hidden>
> To: address@hidden
> References: <address@hidden>  
> <address@hidden> <address@hidden>  
> <address@hidden> <address@hidden>  
> <address@hidden>  
> <address@hidden>
>
> Hello Henrik,
> I haven't forgotten you, nor have I forgotten the gnupod
> I've just been out on a long week-end ;)
> So getting back to our ReplayGain/SoundCheck problem
> I've made 7 files fanfarem9.mp3 fanfarem6.mp3 fanfarem3.mp3
> fanfarep0.mp3 fanfarep3.mp3 fanfarep6.mp3 fanfarep9.mp3.
> Each has an ID3 iTunNORM-comment SoundCheck tag corresponding to
> ReplayGains of -9, -6, -3 0, 3, 6, 9
> The previous fanfare00.mp3 didn't have any RG/SC information as you
> guessed correctly, this time I explicitly put a RG of 0.
> The iTunes and fanfare files are attached and I passed the hexdump/diff:
>
...
>
> It seems obvious that where iTunesSD7.gnupod says 0x000064,
> iTunesSD7.itunes says 0xfffff7, 0xfffffa, 0xfffffd, 0, 0x3, 0x6, 0x9
> I'll check the code when I have some time


Thats is strange indeed. I would never have thought that they would
implement something that crude. Measuring dB in an integer .... 

What strikes me as odd is that in the previous sample the "0" file was taged
as ff ff fb. Following the logic your findings that would rpresent -5dB.
Thats why I asked if that file had any manual volume adjustment in iTunes.
I mean the -100% ... +100% slider that can be used to manualy adjust the
volume independent of the soundcheck values.

>
> H. Langos wrote:
>> Hi chris,
>>
>> On Fri, May 29, 2009 at 12:36:30AM +0200, H. Langos wrote:
>> ...
>>> As you see the gnupod file allways contains 00 00 64 in the volume  
>>> field while the iTunes generated field contains:
>>> ff ff f7 for the -9dB file,
>>> ff ff fb for the 0 file (are you sure it is realy 0? soundcheck 3E8 or none 
>>> at all?),
>>> 00 00 09 for the +9dB
>>>
>>> Unfortunately this is not the format documented in  
>>> http://banshee-project.org/~gburt/itunesdb.html so we'll have to
>>> investigate a little further.
>>>
>>> Are you sure that the manual volume adjustment in iTunes was +/-0% for all
>>> files?
>>>
>>> It would be great if you could send me some more examples with +6dB and -6dB
>>> and maybe +3dB and -3dB.
>>
>> Did you get around to run those additional tests? If you did, please post
>> those to bug-gnupod. 
>>
>> cheers
>> -henrik
>>
>>
>>
>
>