"Gene Pool" wrote in message
...
On Fri, 7 Nov 2003 06:38:40 -0500, "Arny Krueger"
wrote:


All MP3s are effectively converted back to .wav before we hear them.
There's
no way to avoid doing that.


wav is a file type architecture that comes in various format options.

Right, and some of them imbed a lossy-compressed file. I was speaking
generically - .wav file as an uncompressed binary PCM format.


If you are referring to the process of burning mp3's to standard cd
format then they are converted to wav format.

Agreed. CDA is a binary PCM format so some kind of conversion must take
place.

There is no conversion
to .wav format if the playback device (either software or hardware)
can handle the mp3 format (or for that matter .sit, .mod, ,voc, etc ad
nauseum) directly.

If you take the software of a MP3 player apart, you end up with a binary PCM
digital-to-analog conversion device (DAC) that requires a binary PCM input.
That means that the MP3 file is converted to binary PCM and stored in some
working buffer, prior to being shipped off to the sound card.

There is no upward conversion to wav format needed

Sure there is. The DAC chips in sound cards are pretty uncompromising as to
the format of data they require. Look on a sound card or a motherboard and
read the manufacturer names and part numbers. Look those parts up on the
manufacturer's web site. With few if any exceptions, the input data stream
they require is binary PCM plus a clock. That binary PCM is the same binary
PCM as you find in a straight-up .wav file with minor reformatting.

and would degrade the ability of the player to decode various complex
formats on the fly such as VBR at 384k.

Not at all. VBR at 384k still has a lot less binary data than 44/16 stereo.
44/16 stereo is a bitrate of something like 1,300 kb.

Your little mp3 walkman would
choke if it had to convert all sounds to wav before outputting them.

I don't have a MP3 walkman, but I do have a MP3 Nomad 2. Inside its guts,
there's a microprocessor that handles the conversion of MP3 to binary PCM,
and there's the function if not an explicitly chip that does the
digital-to-analog conversion from binary PCM to analog.

Here's a technical overview of such a chip:

http://www.cirrus.com/en/products/pro/detail/P912.html

Relevant and critical text from that page:

"Typical applications for the CS7410 include portable CD-based MP3/WMA
players and boomboxes."

If you look at the right-hand end of the functional block diagram you see a
box labeled "PCM DACs".


For a more detailed explanation, please see:

http://www.itworld.com/Comp/2449/PCW41106/

Again, the block diagram shows a separate DAC chip.

http://www.cirrus.com/en/images/prod...lkdiag_mag.jpg
The final result is merely sound not wav sound. (There may even be
licensing fees associated with wav files knowing Microsoft has a hand
in it.)