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Subject: Re: Gapless Playback Engine
From: BlueChip (cs_bluechip_at_webtribe.net)
Date: 2004-10-24


>>>[Vladimir] IIRC then the playback of mp3 goes over the serial connection,
>>>the recording of mp3 goes over the 8bit parallel interface.
>>
>>[BC] My educated guess is that the link from the chip to the hdd is
>>serial ...We must be able to stream WAV data INTO the chip, else it would
>>not be able to encode it to MP3 ...however, if the link from the chip to
>>the hdd/memory is serial then it would not be able to pump the data back
>>out as fast as it was reading it in?
>
>[Linus] BlueChip,
>
>You really need to start reading up on how the Jukebox is designed.

You wouldn't believe the number of things I need to do with my time ...and
that's BEFORE I inlude the list of things other people want of me ...So
much of life to live, so little time - lol.

>How else can you tell what is possible or not?

I think that's probably rhetoric, as your next paragraph serves as a
perfect answer ...however, two immediate answers spring to mind, Ask and
Guess-and-be-corrected :)

>Recording: The ADC and the encoder is in the same chip. The encoded data
>is transferred to the SH1 via the 8-bit parallel interface (see mpeg.c for
>the transfer routines). The SH1 then saves it to the HDD.
>
>Playback: The data is read by the SH1 from HDD to RAM, and then from RAM
>with DMA to a serial port of the SH1, connected to the serial interface of
>the MAS. It is the decoded and fed to the internal DAC.

Cool ...so in theory, WAV _could_ be recorded?
Not of much interest to myself, but I'm sure some would enjoy that as a
feature ...If nothing else it would stir up the CODEC writing brigade :)

>And yes, we have quite a lot of documentation on how to write code for the
>MAS, but so far nobody has done anything useful with it.

Yes, it would seem that way ...unless there are things going on that are
not being publicised - which is always an optimistic possibility - and
quite common with Rockbox :)

Your choice of words ("so far") suggests that 'Rockbox' is now prepared to
accept CODECs which may be submitted ...that alone is the greatest move
forward from my point of view.

>(btw, Vladimir knows what he's talking about)

Handy - is he up for working on CODECs, do you know?
...If so, someone should furnish him with all available information; such
as the plugin to upload CODECs, example CODECs, Programmers manual,
Translated lecture slides, etc. etc.

Let me know if I can help in any way.

Enjoy,

BlueChip

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