Re: [Bug-gnupod] SoundCheck/ReplayGain

[chris.com]

H. Langos wrote:
> Hi chris,
>
> I borrowed an ipod shuffle 3gen (what apple calls "iPod shuffle 2nd 
> generation Early 2008") from a collegue but that one seems to be
> up to date too. All the volume adjustment fields are "00 00 00"
>
> Does the "revision" as shown by udev represent the firmware
> version?
> > ID_VENDOR=Apple
> > ID_MODEL=iPod
> > ID_REVISION=2.70
>
> If iTunes shows the firmware version somewhere in device information
> you could compare it to the output of
>   udevinfo --path /sys/block/sda --query env
> or
>   /sbin/udevadm info --path /sys/block/sda --query env
Actually I have a Firmware-131.1.0.3 loaded and I get:
ID_VENDOR=Apple
ID_MODEL=iPod
ID_REVISION=2.70
> > I'm still playing around with ReplayGain and SoundCheck
> > In particular I'm trying to see if there is a 1:1 ratio between RG and
> > SC or not.
> > I found they iTunes-SC values clearly unsatisfying so I'm trying SC
> > calculated from RG now but I'm not done yet :)
>
> Well, you know that Richard and I implemented replaygain to sc conversion
> in april/early may, don't you?
>
> The current CVS version of gnupod will take in this order
>
>   RVA2/XRVA tags,
> or
>   "replay_album/track_gain" from APE tags or id3 TXXX tags
> or
>   iTunes soundcheck values (as found in iTuneNORM comment tags) plus RVAD
>   tags (iTunes way of encoding the -100%..+100% volume slider)
>
> Check out the the mailing list's archive
> http://www.mail-archive.com/address@hidden/index.html#00222
Yes I will upgrade to the CVS version soon
> Implementing the conversion from soundcheck or any other volume adjustment
> value to something the ipod understands is very easy. I'd do it a 5 minutes
> if we find out how to distinguish between old ipod shuffles that interpreted
> the volume field as "100 minus volume adjustment in percent" and those who
> interpret it as "signed integer for volume adjustmend in dB".
>
> Currently gnupod writes a value of 100 into that field. Now according to the
> new semantics of that field this would mean a gain of +100dB.
> Obviously the "new" iPod shuffle ignores those values or your ear drums would
> simply go "pop".
>
> Now what we don't know is how and "old" iPod who expects that 0..200 value
> will react to the values outside that range. Something like "00 00 03" would
> probably be interpreted as "-97%" instead of "+3dB" but how will it
> interpret a value of "FF FF FB"? Your guess is as good as mine.
>
> > Finding itunes 7.4 was really easy
> > but where might I well find an old firmware for a 2nd generation shuffle?
> > Anyone have an idea?
>
> Google? Just look for "ipod" and "firmware" and the first hit was this:
> http://www.felixbruns.de/iPod/firmware/
Well, I tried that.
I downloaded the iPod_130.1.0.3.ipsw and iPod_131.1.0.3.ipsw firmware 
from appldnld.apple.com.edgesuite.net.
The Firmware part is identical and when connected to iTunes the firmware 
version shown is "1.0.4" for both of 'm.
felixburns has a 133 version, I guess it is more recent. I haven't tried it.

Do you want me to load a 130 firmware and send you the iTunesSD?

> Or just google for "ipod firmware downgrade" and I am pretty sure you'll
> find what you need.
>
> cheers
> -henrik