Digitizing audio cassettes and extracting the contents of digital cartridges.

[Linux for blind general discussion]

If we need to continue this conversation, I should just get your e-mail address so we don't clutter this listserv. 
Daisy books typically encode their audio in MP3 at bitrates of 32 kbps or higher. FLAC probably averages around 300 kbps (I haven't checked this lately) for monophonic audio. 
NLS uses the adaptive multirate wideband extended (AMR-WB+) encoding format of the Third Generation Partnership Project, and we encode our books at 24 kbps constant bitrate. This algorithm can be set to bitrates as low as 5.5 kbps, but quality suffers.
I have been advocating the adoption of the Opus internet wideband audio codec for audio EPUB files, but so far this hasn't gained much traction. It works about as well as AMR-WB+ at a given bitrate and is royaltee-free. I don't expect to see opus used for talking books any time soon, and probably not on the current generation of hardware players. 

Lloyd Rasmussen, Senior Staff Engineer
National Library Service for the Blind and Physically Handicapped, Library of Congress
Washington, DC 20542   202-707-0535
http://www.loc.gov/nls/
The preceding opinions are my own and do not necessarily reflect those of the Library of Congress, NLS.


-----Original Message-----
From: blinux-list-bounces at redhat.com [mailto:blinux-list-bounces at redhat.com] On Behalf Of Linux for blind general discussion
Sent: Monday, September 11, 2017 8:41 PM
To: blinux-list at redhat.com
Subject: Re: Digitizing audio cassettes and extracting the contents of digital cartridges.

I find the claim that most could fit their entire library on a 16GB
cartridge funny considering my own fairly modest library of audiobooks
and eBooks takes up 66GB in my home directory not counting the stuff
in my Unread folder. Granted, most of the audiobooks saved on my
computer are flac rips from Audiobooks I bought in CD format off of
Amazon and are thus much bigger than mp3 versions would be, and while
I know next to nothing about the Daisy format, I'm guessing its closer
in size to mp3 than flac.

-- 
Sincerely,

Jeffery Wright
President Emeritus, Nu Nu Chapter, Phi Theta Kappa.
Former Secretary, Student Government Association, College of the Albemarle.

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