Talking books file compression

Hi
I'm copying .mp3 audio files to cd-r for a visually impared person
These are talking books and depending on the size of the files I can
usually get about an hour of the book on an 80 min cd-r

This person gets talking books on cd from the talking books for the
blind library and he recently got one which was 70 hours listening
time long

How do they manage that - what format is used -
would I be able to do it ???

Martin
©¿©¬

On Thu, 28 Jul 2005 14:55:14 +0100, Martin ©¿©¬ @REMOVETHIS.plus.com
wrote:

Hi
I'm copying .mp3 audio files to cd-r for a visually impared person
These are talking books and depending on the size of the files I can
usually get about an hour of the book on an 80 min cd-r

This person gets talking books on cd from the talking books for the
blind library and he recently got one which was 70 hours listening
time long

How do they manage that - what format is used -
would I be able to do it ???

Martin
©¿©¬

Are you sure it wasnt on a DVD? You can set audio compression to
various levels - less quality more compression for smaller files and
of course DVDs are larger. If its a commercial DVD they can hold twice
as much as a writable DVD. Ive seen descriptions of 70 hours
narration and text supposedly crammed on TWO DVDs. So I guess they
could do it on one.

Who knows I dont listen to books on CDRs so I really dont know what
sizes /quality files of voice recordings fit on CDRs - so maybe they
can fit far more than I think though 70 hours sounds like a huge
amount of time.

Maybe they could use a code to trigger a talking machine you know like
Steven Hawkings talking machine. I bet that could be pretty compact.
Theres got to be a fairly limited amount of words used over and over
and over again in many books. I can picture the Alexandria Quartet
delivered in monotone machine like fashion.

On Thu, 28 Jul 2005 14:55:14 +0100, Martin ©¿©¬ @REMOVETHIS.plus.com
wrote:

Hi
I'm copying .mp3 audio files to cd-r for a visually impared person
These are talking books and depending on the size of the files I can
usually get about an hour of the book on an 80 min cd-r

This person gets talking books on cd from the talking books for the
blind library and he recently got one which was 70 hours listening
time long

How do they manage that - what format is used -
would I be able to do it ???

Martin
©¿©¬

You know out of curiousity I looked it up and it seems possible

Heres a audible book site.


----------------------------------------------------------------
How Many Megabytes is an Audible Book

Audible sound files are available in four different levels of sound
compression and quality :


Audible Rating

MB per Hour
Download time per hour of material (56k/broadband)
Quality

1 - Fair
Telephone Like
2 MB
7/1 minutes
Bad

2 - Good
AM radio
4
12/1
Fair

3 - Good
FM radio
7
22/2
Good

4 - Excellent
MP3
14
44/5
V Good


Obviously, the more compressed a book, the less space it requires, and
the faster the download.

Space is not really a problem on the huge hard-drives available today,
but it is a massive constraint on some of the smaller portable playing
devices (such as the Creative Nomad offered by Audible). While the
Apple iPod has a 20GB hard drive, the Nomad has only 128 MB, and other
similar devices generally have between 64MB and 256MB. So if you want
to take your books with you, there is strong reason to get the most
compressed file size possible.

Unfortunately, you don't get something for nothing, and the compromise
you must accept is that the smaller the file size, the poorer the
sound quality. The smallest file size, with the greatest compression,
gives a low sound quality that probably would become tiring to listen
to for an extended period.

Note also that Audible's level 1 compression is incompatible with
portable MP3 players, it only works on computers and Pocket PC
devices.

Indeed, not all portable devices support all three other compression
levels, either. Most will support levels 2 and 3, and a few will also
support level 4.

You should normally choose level 2 or 3 for your downloads. You can
play samples of all four formats from this page on the Audible site to
choose which sound level you're comfortable with.

The 32 kb/sec rate of Audible's best audio quality is still very much
lower than the 192kb/sec I recommend for making music MP3s. But voice
recording needs very much less bandwidth than music recording, so the
32 kb/sec is more than adequate for most people.

How Many Books Can You Fit on an MP3 Player

If we say an average book is 10 hours, then you are looking at either
40MB or 70MB (for level 2 or 3 compression) per book.

The Creative Muvo player offered for free with new one year signups
holds 128MB of audio. This means you could fit three regular books in
lower quality audio, or one regular and one short book in higher
quality audio onto the player.

Expressed another way, 128MB can hold between 17 and 34 hours of
audio.

If you choose to load books onto a higher capacity 20GB iPod, then you
could get a massive 2,650 - 5,300 hours of audio on the unit - more
than enough for your next long flight somewhere! Even if you set
aside 'only' 1 GB for audio books and keep the rest for music, that
still gives you 125 - 250 hours for books and magazines.

If you look at the bandwidth of standard telephone it used to be quite
restricted. Speech doesn't require anywhere near the bandwidth of music. I
can't quote actual numbers offhand, but am not surprised by the figure
given. I get about 10 hours on music cd's that sound good to my aged ears.
Dave Cohen

" wrote in message
news
On Thu, 28 Jul 2005 14:55:14 +0100, Martin ©¿©¬ @REMOVETHIS.plus.com
wrote:

Hi
I'm copying .mp3 audio files to cd-r for a visually impared person
These are talking books and depending on the size of the files I can
usually get about an hour of the book on an 80 min cd-r

This person gets talking books on cd from the talking books for the
blind library and he recently got one which was 70 hours listening
time long

How do they manage that - what format is used -
would I be able to do it ???

Martin
©¿©¬

You know out of curiousity I looked it up and it seems possible

Heres a audible book site.


----------------------------------------------------------------
How Many Megabytes is an Audible Book

Audible sound files are available in four different levels of sound
compression and quality :


Audible Rating

MB per Hour
Download time per hour of material (56k/broadband)
Quality

1 - Fair
Telephone Like
2 MB
7/1 minutes
Bad

2 - Good
AM radio
4
12/1
Fair

3 - Good
FM radio
7
22/2
Good

4 - Excellent
MP3
14
44/5
V Good


Obviously, the more compressed a book, the less space it requires, and
the faster the download.

Space is not really a problem on the huge hard-drives available today,
but it is a massive constraint on some of the smaller portable playing
devices (such as the Creative Nomad offered by Audible). While the
Apple iPod has a 20GB hard drive, the Nomad has only 128 MB, and other
similar devices generally have between 64MB and 256MB. So if you want
to take your books with you, there is strong reason to get the most
compressed file size possible.

Unfortunately, you don't get something for nothing, and the compromise
you must accept is that the smaller the file size, the poorer the
sound quality. The smallest file size, with the greatest compression,
gives a low sound quality that probably would become tiring to listen
to for an extended period.

Note also that Audible's level 1 compression is incompatible with
portable MP3 players, it only works on computers and Pocket PC
devices.

Indeed, not all portable devices support all three other compression
levels, either. Most will support levels 2 and 3, and a few will also
support level 4.

You should normally choose level 2 or 3 for your downloads. You can
play samples of all four formats from this page on the Audible site to
choose which sound level you're comfortable with.

The 32 kb/sec rate of Audible's best audio quality is still very much
lower than the 192kb/sec I recommend for making music MP3s. But voice
recording needs very much less bandwidth than music recording, so the
32 kb/sec is more than adequate for most people.

How Many Books Can You Fit on an MP3 Player

If we say an average book is 10 hours, then you are looking at either
40MB or 70MB (for level 2 or 3 compression) per book.

The Creative Muvo player offered for free with new one year signups
holds 128MB of audio. This means you could fit three regular books in
lower quality audio, or one regular and one short book in higher
quality audio onto the player.

Expressed another way, 128MB can hold between 17 and 34 hours of
audio.

If you choose to load books onto a higher capacity 20GB iPod, then you
could get a massive 2,650 - 5,300 hours of audio on the unit - more
than enough for your next long flight somewhere! Even if you set
aside 'only' 1 GB for audio books and keep the rest for music, that
still gives you 125 - 250 hours for books and magazines.

Dave Cohen wrote:
If you look at the bandwidth of standard telephone it used to be quite
restricted. Speech doesn't require anywhere near the bandwidth of music. I
can't quote actual numbers offhand, but am not surprised by the figure
given. I get about 10 hours on music cd's that sound good to my aged ears.
Dave Cohen

" wrote in message
news
On Thu, 28 Jul 2005 14:55:14 +0100, Martin ©¿©¬ @REMOVETHIS.plus.com
wrote:


Hi
I'm copying .mp3 audio files to cd-r for a visually impared person
These are talking books and depending on the size of the files I can
usually get about an hour of the book on an 80 min cd-r

This person gets talking books on cd from the talking books for the
blind library and he recently got one which was 70 hours listening
time long

How do they manage that - what format is used -
would I be able to do it ???

Martin
©¿©¬

You know out of curiousity I looked it up and it seems possible

Heres a audible book site.


----------------------------------------------------------------
How Many Megabytes is an Audible Book

Audible sound files are available in four different levels of sound
compression and quality :


Audible Rating

MB per Hour
Download time per hour of material (56k/broadband)
Quality

1 - Fair
Telephone Like
2 MB
7/1 minutes
Bad

2 - Good
AM radio
4
12/1
Fair

3 - Good
FM radio
7
22/2
Good

4 - Excellent
MP3
14
44/5
V Good


Obviously, the more compressed a book, the less space it requires, and
the faster the download.

Space is not really a problem on the huge hard-drives available today,
but it is a massive constraint on some of the smaller portable playing
devices (such as the Creative Nomad offered by Audible). While the
Apple iPod has a 20GB hard drive, the Nomad has only 128 MB, and other
similar devices generally have between 64MB and 256MB. So if you want
to take your books with you, there is strong reason to get the most
compressed file size possible.

Unfortunately, you don't get something for nothing, and the compromise
you must accept is that the smaller the file size, the poorer the
sound quality. The smallest file size, with the greatest compression,
gives a low sound quality that probably would become tiring to listen
to for an extended period.

Note also that Audible's level 1 compression is incompatible with
portable MP3 players, it only works on computers and Pocket PC
devices.

Indeed, not all portable devices support all three other compression
levels, either. Most will support levels 2 and 3, and a few will also
support level 4.

You should normally choose level 2 or 3 for your downloads. You can
play samples of all four formats from this page on the Audible site to
choose which sound level you're comfortable with.

The 32 kb/sec rate of Audible's best audio quality is still very much
lower than the 192kb/sec I recommend for making music MP3s. But voice
recording needs very much less bandwidth than music recording, so the
32 kb/sec is more than adequate for most people.

How Many Books Can You Fit on an MP3 Player

If we say an average book is 10 hours, then you are looking at either
40MB or 70MB (for level 2 or 3 compression) per book.

The Creative Muvo player offered for free with new one year signups
holds 128MB of audio. This means you could fit three regular books in
lower quality audio, or one regular and one short book in higher
quality audio onto the player.

Expressed another way, 128MB can hold between 17 and 34 hours of
audio.

If you choose to load books onto a higher capacity 20GB iPod, then you
could get a massive 2,650 - 5,300 hours of audio on the unit - more
than enough for your next long flight somewhere! Even if you set
aside 'only' 1 GB for audio books and keep the rest for music, that
still gives you 125 - 250 hours for books and magazines.



Typically you could reproduce speech with 300-6KC bandwidth. That's a
lot narrower than 300-10KC for typical computer speakers, and just a
blip for the 20-100KC most people want for home work. The higher
frequency for home use is to avoid distortion of the higher notes, etc.

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If the recipient has a player that supports mp3 files (computer, most DVD
decks, MP3 CD Walkman type player) burn you cd-r as a data file, which would
hold at a minimum several hours. The "hour" you are getting means you are
making an audio CD.
Martin ©¿©¬ @REMOVETHIS.plus.com wrote in message
...
Hi
I'm copying .mp3 audio files to cd-r for a visually impared person
These are talking books and depending on the size of the files I can
usually get about an hour of the book on an 80 min cd-r

This person gets talking books on cd from the talking books for the
blind library and he recently got one which was 70 hours listening
time long

How do they manage that - what format is used -
would I be able to do it ???

Martin
©¿©¬

Martin ©¿©¬ @REMOVETHIS.plus.com wrote:
Hi
I'm copying .mp3 audio files to cd-r for a visually impared person
These are talking books and depending on the size of the files I can
usually get about an hour of the book on an 80 min cd-r

This person gets talking books on cd from the talking books for the
blind library and he recently got one which was 70 hours listening
time long

How do they manage that - what format is used -
would I be able to do it ???

They are data discs in one of the lossy formats: MP2, MP3, WMA, ...

From 70 hours per disc, compression is to about 16 Kbps, giving
high-end response ending at about 3.75 KHz (and monaural, of course).
For my own use - old recordings of music as well as spoken material - I
usually use 32 Kbps. For example, I transferred the first four Harry
Potter books to a single CD-ROM. Sound quality is fine for listening
while walking, etc.

Just create the appropriate format file compressed to the same format as
your friend is using now. Check one of the discs he borrows to see the
format, rate, file naming system, etc. - then match it.

Mike
--

http://www.mrichter.com/