With the low price of flash-mem and maturity of mp3, I'm surprised that 'talking books' are not commonly available - cheaply; where you would just change flash-cards.
Syncronising the 'writing with the sound' would also be good for language learning ?
Perhaps even minimal cartoon-like graphics for stories for kiddies ?
Who knows about the Blackfin CPU from Analog devices ?
Thanks for any info,
== Chris Glur.
They are sold. Barnes & Noble sells them. They are NOT cheap and they do NOT use removable media. They also don't use MP3 encoding, they use a proprietary CELP system. The only application where this has sold significant volumes is talking religious texts, but there is some mainstream content also.
The difficulty of course is licensing the content. Not a lot of interest.
This is usually done by having a low-frequency control signal embedded in the audio stream. Same principle is used to synchronize mouth movement on speaking toys.
You likely wouldn't use it for this sort of application, you'd use an ASIC.
You just go back and do things the old way.
MP3 players are stereo. So you have one track for the audio, and then the other track to control the slide projector. At the right moment, there's a beep in the control track, which then tells the slide projector to advance. If you're willing to add fancy circuitry, then there's more you can do, simply by using more complicated control scheme than just a beep. Multiple beeps or different tones, or modulate the tone, and then you have a audio decoder to handle it all.
This is nothing new. It was done back in the days of slide projectors, with stereo tape decks.
Michael
In practice, it isn't done this way. The last product I'm aware of that used an entire channel of a stereo recording for this purpose was Teddy Ruxpin.
The control information is encoded as very low frequency audio, and the playback has a high-pass filter to remove control tones.
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