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Subject: Re: the ALDI rockbox?

Re: the ALDI rockbox?

From: BlueChip <cs_bluechip_at_webtribe.net>
Date: 2005-02-22

>>>>iirc they also had a pitch-shift algorithm in their MAS code ...I
>
>>When you examine their code, you will find the details on how this is
>>implemented. It's not that difficult to port it over to Rockbox.
>
>Well, now you got me curious. So, how is it done?

Possibly the biggest clue is this snippet from the m3po version history
[numbered by me for clarity]:

2.10 >> V2.11
[Bugfixes]
1. party lock - eject cds while lock complete
2. pitch and speed of playback was wrong
3. minor shuffle bug fixed
4. more files on one CD supported

When I read that I get:
3. this list includes all changes to firmware
4. a buffer/malloc/bss got bigger somewhere
2. the pitch/speed code was tweaked
1. & 3. two other bits of code also changed

There are no binary attachments allowed here, so if you want these two
files, please contact me offline.

Ever play "spot the difference" on a pub quiz machine? ...One of the
differences directly effects the pitch/speed change ;)

My next hit is a mind-numbingly simple moment of genuis called FTEXT, an
ancient DOS util which isolates ascii strings in unencrypted binary files -
you would not be surprised at how far you can get by simply tracing things
from the point they print "speed" on the screen.

Of course the change must also be pesent in the comms to the MAS, so you
can home in on what you are looking for with an "A*" approach (bidirection
search methodology) by now.

Grab yourself a good hex editor [and please tell me what it is - LOL - I
have NEVER found a _good_ hex editor (or calculator) for windows] and "hit
the bits" as they say.

BC

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Received on Tue Feb 22 18:09:13 2005


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