[vorbis] embedded vorbis players

[Matt Hodge]

> What would interest me is how much knowledge of electronics does one
> have to have to build such a player?

It shouldn't take a huge amount, to get something working, starting from
scratch.  Production can be more difficult than design. There are only a
few major components that do the bulk of the work, such as a processor,
D/A, A/D (if you want to record as well), memory, interface to download
code into it, user interface, and power supply. Often you only need very
simple or no "glue" components between the major components. By reading
the datasheets for the major components, which are on the manufacturers'
web pages, you can usually figure out most of the rest of the stuff you
need and how to connect it together.

You can buy development boards for devices like processors. These may
contain most of the other major components already. For example, some DSP
development boards will contain audio codecs. You can then just more or
less copy the portion(s) of the development board that you need.

Once you have a logical circuit design you need to physically lay them
out, usually by designing a printed circuit board (PCB). Some general
knowledge of good circuit layout techniques helps here. Design the PCB on
your computer, send it to a company to print out a few copies (kind of
expensive) or try and fabricate them yourself (probably not as good
quality). Then solder the components on and test. As they make parts
smaller and smaller and pack those pins in tighter and tighter, hand
soldering becomes tougher and tougher. You can always pay to have
someone's machine put the parts on the board for you.

That's the hardware. Then you have to write software.

> I've also heard of these MP3 chips like the MAS series that are designed
> to play MP3 music, are there similiar chips designed for OGG?

The mp3 chips can greatly reduce the processor requirements, to the point
where a dinky 8-bit microcontroller or FPGA may suffice. But I really
doubt there are any OGG chips yet. I imagine there would have to be a fair
number of OGG players selling before they would start making such
specialized chips.

What I'm currently thinking of is:

- compact flash / microdrive for bulk storage (they both use the same
  interface).
- Analog Devices SHARC DSP (32-bit, floating point). Maybe an ADSP-21065L
  would work. I have a development board for an ADSP-21061 (with audio
  codec), so I can start on the software anytime.
- High quality A/D and D/A. Maybe Cirrus CS5396 and CS4396. It will record and
  playback uncompressed audio as well. Not sure if there is enough DSP
  power to compress (encode) while recording.

Matt

On Fri, 21 Dec 2001, Erik Fuller wrote:

<p>>
> --
> GMX - Die Kommunikationsplattform im Internet.
> http://www.gmx.net
>
>
> --- >8 ----
> List archives:  http://www.xiph.org/archives/
> Ogg project homepage: http://www.xiph.org/ogg/
> To unsubscribe from this list, send a message to 'vorbis-request at xiph.org'
> containing only the word 'unsubscribe' in the body.  No subject is needed.
> Unsubscribe messages sent to the list will be ignored/filtered.
>

<p><p>--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.