OT. PLaying recorded audio

In article ,
Paul Ratcliffe wrote:
CDs do use plain wav files. It's everything else that doesn't. ;-)

Audio CDs don't use files at all.

Indeed - but is being rather pedantic for this thread.

They use uncompressed audio sample data.

A WAV file is a container for that data, with a header to describe
its format.

Which is also the type for uncompressed data - the sort used when making a
CD on a computer. As per the thread. ;-)

This is not present on an audio CD.

I don't think it would matter if it were.

--
*I finally got my head together, now my body is falling apart.

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Paul Ratcliffe
wrote:
On Tue, 16 Dec 2008 01:10:02 +0000 (GMT), Dave Plowman (News)
wrote:

In article , Brian Gaff
wrote:
The basic thing is, as far as my memory reminds me, its got to burn
in the old red book format and thus convert the wav or whatever, to a
stream of data for writing to that format.

CDs do use plain wav files. It's everything else that doesn't. ;-)

Audio CDs don't use files at all. They use uncompressed audio sample
data. A WAV file is a container for that data, with a header to describe
its format. This is not present on an audio CD.

Interesting coincidence where I have just read some comments in an audio
magazine where the author asserts that:

"...there is no music on an Audio CD. The disc contains a directory of
files. A CD Player is a straightforward playback computer designed to
navigate the file directory..."

Firstly, you can just as easily assert that there is no 'music' on an LP,
analogue tape, etc, etc, either. All these systems record/replay patterns
which can be used for the storage and replay of sound patterns. (Indeed, as
I've witnessed recently, you can use an 'Audio CD' to record waveforms for
a slow-scan video waveforms for suppling images to something like a demo of
how 'Baird Televisors' work. Just as Baird himself used analogue discs for
making 'video' recordings for use with his system.

Secondly, as you point out above, Red Book Audio CD doesn't have any
'files' or 'directories' in the sense normally used for computer filing
systems. Nor is a normal CD player a 'computer' since that implies general
programmability. Turing, Neumann, etc...

So, hardly surprising people think such things if it appears in magazines,
etc, where the authors may be presumed to know what they are talking about.
:-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article , J G Miller wrote:
On Tue, 16 Dec 2008 09:02:21 +0000, Paul Ratcliffe wrote:

Audio CDs don't use files at all.

However the data on audio compact discs *appears* to be stored in files
designated .cda, with each one being a pointer to each of the CD audio
tracks.

You failed to specify which OS and pseudo-filer combination(s) give that
*appearance*.

No such filetype extension is visible with the pseudo-filers/OS I use for
such discs when accessing them using my own computer - or at least the one
I use for most audio work. :-)

And as your careful wording makes clear, what you describe is simply a form
of presentation interface employed by some specific forms of computer or
other system that isn't simply a Red Book standard player.

If you wish to refer to Red Book discs and players, what Paul wrote is
essentially correct.

if you wish to give no device or format dependence, then all CDs are simply
discs with patterns of pits whose 'meaning' can only be defined by then
applying a given coding standard.

It is clearly possible to use a computer to create or replays Red Book
Audio CDs. This is a consequence of the ability of a general computer to
carry out an arbitrary range of information functions as defined by the
programs it carries out. This does not mean a Player is a Computer. Nor
that the disc holds files or directories. Data is not Information. A Tin
is not a Tomato. :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

A WAV file is a container for that data, with a header to describe
its format.

Which is also the type for uncompressed data - the sort used when making a
CD on a computer. As per the thread. ;-)

A WAV file doesn't necessarily contain uncompressed audio though. You can
just as easily have a WAV file that contains MPEG audio.

In article ,
dB wrote:
Which is also the type for uncompressed data - the sort used when
making a CD on a computer. As per the thread. ;-)

A WAV file doesn't necessarily contain uncompressed audio though. You
can just as easily have a WAV file that contains MPEG audio.

Ah. In which case ignore everything I'd said. That can't be difficult. ;-)
In my machine Wave files are always uncompressed.

--
*I used to have an open mind but my brains kept falling out *

Dave Plowman London SW
To e-mail, change noise into sound.

On Tue, 16 Dec 2008 15:07:08 +0100, J G Miller wrote:

Audio CDs don't use files at all.

However the data on audio compact discs *appears* to be stored in
files designated .cda, with each one being a pointer to each of
the CD audio tracks.

That's only some program's pretty front end designed to pacify dumb
windoze users I expect.
This doesn't change the reality of what is on the disk.

On Tue, 16 Dec 2008 14:35:03 +0000 (GMT), Dave Plowman (News)
wrote:

CDs do use plain wav files. It's everything else that doesn't. ;-)

Audio CDs don't use files at all.

Indeed - but is being rather pedantic for this thread.

I disagree. Why can't you just accept you are wrong rather than trying to
wriggle out of it by claiming pedantry?

A WAV file is a container for that data, with a header to describe
its format.
This is not present on an audio CD.

I don't think it would matter if it were.

Of course it would. If you try to play the header as RAW PCM audio data
then you get a nasty splat.

On Tue, 16 Dec 2008 15:22:20 +0000 (GMT), Jim Lesurf
wrote:

Audio CDs don't use files at all. They use uncompressed audio sample
data. A WAV file is a container for that data, with a header to describe
its format. This is not present on an audio CD.

Interesting coincidence where I have just read some comments in an audio
magazine where the author asserts that:

"...there is no music on an Audio CD. The disc contains a directory of
files. A CD Player is a straightforward playback computer designed to
navigate the file directory..."

Long ago I came to realise that book authors and magazine column writers
didn't always know what they were talking about. It's a bit like the
internet really. You can get complete and utter ******** from any source.

So, hardly surprising people think such things if it appears in magazines,
etc, where the authors may be presumed to know what they are talking about.
:-)

This is why it is important to correct these misapprehensions and why people
like Plowman are so annoying when they try to squirm out of admitting it.

On Tue, 16 Dec 2008 15:36:20 +0000 (GMT), Jim Lesurf
wrote:

Audio CDs don't use files at all.

However the data on audio compact discs *appears* to be stored in files
designated .cda, with each one being a pointer to each of the CD audio
tracks.

You failed to specify which OS and pseudo-filer combination(s) give that
*appearance*.

No such filetype extension is visible with the pseudo-filers/OS I use for
such discs when accessing them using my own computer - or at least the one
I use for most audio work. :-)

Likewise. I have used a program that makes an audio CD look like a data CD -
it works in much the same way as mounting a network drive does.
It gives you a directory listing containing .WAV and .RAW files and various
bits of metadata.

In article , Paul Ratcliffe
wrote:


Long ago I came to realise that book authors and magazine column writers
didn't always know what they were talking about. It's a bit like the
internet really. You can get complete and utter ******** from any source.

That can, alas, also extend to areas like educational and professional
textbooks. Since I used to lecture and work in related areas I have read a
number of uni textbooks on topics like Electromagnetics and Information
Theory. Having done so I have encountered a number of incorrect or muddled
'explanations' that seem to propagate from one generation of texts to the
next. Presumably because each author in turn faithfully 'learned' them from
a textbook, taught them, and duitfully re-worded them when they wrote a
book of their own. Analog with the way many undergrads develop a direct
link from their ears to their hand so as to be able to take lecture notes
without actually having to understand what they'd just written down. Mind
bypass engaged. :-)

In some topics actually understanding the basics can be made quite
difficult by such behaviour. It is understandable that students find the
topics 'hard'. But they then tend to be lead to assume this is because the
topic is inherently difficult. So may then fail to twig when an explanation
is difficult to follow simply because it is actually garbled/incorrect.

I've always found it useful to try and work out things for myself, checking
against textbooks as I proceeded. This can make progress much slower, but
makes it easier to spot when a standard explanation might be dubious. I
also found it helped to develop a 'critical' approach which seemed improve
my ability to detect when a new idea was probably flawed. This can be quite
useful in areas like 'audio' engineering where there seems to be quite a
lot of BS littering the ground in some places, but also some intriguing
areas where things are not well understood.

Shame that 'forensic science' as a phrase now has a specific meaning. I'd
prefer it to be almost a tautology for how people should behave in science
and engineering.

FWIW I did try to teach this cautious/critical approach to others, but with
mixed success. Alas, many just want to be told 'what do I need to pass the
exam?' or its equivalents in various areas of employment. :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html