Hi Greg,
Yes, playing back one of the 1/4 speed tapes back at normal speed
should work OK (I'll leave it to you to figure out the amount of
pitch correction to be applied). Tone detection is another matter.
I've spent about 8 years doing that kind of weird specialized work.
It can be a hard nut - if you're trying to make it automated -
depending on the quality of the source audio and index tones. On the
big automated system I referred to earlier tone detection was done in
realtime. This last year I wrote an application called Tone Detective
(as a work for hire). That software is designed to work with pretty
good quality audio and index tones which stick pretty closely to a
published specification. It's being used by one of the libraries as a
post-production tool to automatically detect index tones in audio
that has already been digitized. Here's link to more information on
Tone Detective at the KD web site:
http://www.kafkasdaytime.com/tonedetective/
There's some more or less good news on the katieplayer development
front which I will post in the katieblog before long. As you know,
katieplayer is self-funded by me and proceeds from my other
development work. I believe I now have enough put aside to push
through the last development steps to complete katieplayer Cocoa.
That is, I have enough to commit the time and pay contributing
programmers who have been involved in the project from the beginning.
I'm going to host a few "programming retreats" which will put us
(few) in a room together for a few days at a time and really bang out
the last work. I think that more aggressive approach will bring us to
beta testing and release dates much more quickly and probably more
inexpensively over the long run. I don't have dates yet but things
are looking much better now than they were, say, 2 months ago.
Obviously, I'm also comfortable discussing this stuff publicly since
I'm posting to the list so please feel free to share this information.
Joe
On Dec 28, 2006, at 10:52 AM, Greg Kearney wrote:
Joe;
Let's say I use one of the NLS players playing back at normal tape
speed a NLS book which was recoded at 1/4 speed. Would that work?
Also would it be possible to detect the tone indexes on the NLS
tapes such that the recording could be broken down into seperate
recoding? I'm trying to devise a method of converting NLS books
into Daisy recordings.
By the way I have been pushing Daisy playback hard at Apple. I've
had a few meeting with the documentation people there about it. Any
word on when I can try out your latest work? I'm beta testing 10.5
as well as the new NLS Daisy books now.
Greg
On Dec 28, 2006, at 08:43 , Kafka's Daytime wrote:
Hi Greg,
I built a system for one of the libraries that did/does automated
conversion of taped audiobooks to digital. To speed the process
significantly, we custom-modified tape machines to play at higher
speeds and then pitch-shifted the digitally recorded audio to
return to normal speed. I don't recall what the threshold was, but
you have to find a happy balance between speed going in (and
resulting bandwidth loss) and artifacts resulting from pitch-
shifting (i.e. if you go in too fast your audio will get mangled
in a too-dramatic pitch shift and bandwidth loss will be too great).
For a home version, you might be able to use one of the Marantz
tape players (or Narrator model or similar) to play taped audio in
at higher speed - into Audalyze, for instance - and then apply
pitch shift to slow audio down.
Ripping at Fast Forward speed will not work as all of the audio's
frequency information gets mangled when played at Fast Forward and
the Fast Forward speeds will generally be too fast i.e. the factor
of pitch shift required and bandwidth lost will be too great.
There is more information in the patent abstract if you care to
search USPTO.gov for patent number 6,710,955.
Hope that helps,
Joe
On Dec 28, 2006, at 9:42 AM, Greg Kearney wrote:
While we're on this topic I would like to know if there is a way
to rip tapes at fast forward speed and then slow them dow to
normal speed in the computer. This would speed up the process of
ripping taped books as you would not have to play them into the
sound recoding software at the normal speed.
Greg Kearney
On Dec 27, 2006, at 22:19 , louie wrote:
Also you can rip NLS tapes using sound studio.
On Dec 27, 2006, at 9:03 PM, Cheryl Homiak wrote:
Our local libraries here in Madison have a lot more on cassette
than on cd as far as books and quite a few of them are
abridged, which I hate. but for books which are available this
certainly works and in fact, with a line-in setup and audio
hijack pro it isn't really difficult to make files of cassettes
either.
--
Cheryl
"Where your treasure is, there will your heart be also."
