Menneisyys: "Advanced Sound Recorders on the Pocket PC"

[Darius Wey]

<div class='os_post_top_link'><a href='http://menneisyys.freeweb.hu/mp3/' target='_blank'>http://menneisyys.freeweb.hu/mp3/</a><br /><br /></div><i>"Up until late 2002, there were no real MP3 encoders for the Pocket PC. This meant anyone that wanted to record on his or her PDA needed to resort to the built-in, either very wasteful, non-compressing WAV coders or (on the PPC2k2 platform; in PPC2k and earlier, there was another ultra-low-speed codec, the Mobile Voice, with even worse voice quality and smaller bandwidth usage) the GSM codec, which, being a heavy-compression vocoder, produced just intelligible results and was completely useless for recording for example meetings."</i><br /><br />Pocket PC Thoughts reader, <i>Menneisyys</i>, has just put together an interesting article on many of today's sound recorders for the Pocket PC. If you're interested in finding out more about the ups and downs of each application, then this article is worth a read.

[Menneisyys]

Ohhh... thanks :)

BTW, I've just added a section on Scheduling and Screen off capabilities.

[Nat]

"Furthermore, it's impossible to come up with a CF/SD card that would have direct sound feeding via the card bus to the inner hardware – the current card buses just don't support this kind of functionality. "

I have to disagree with this statement.

http://www.core-sound.com/pdaudio-cf.html

Core sound makes a SPDIF CF card that can record up to 24 bit 96khz. It's used by a lot of pros in the industry.

[Menneisyys]

"Furthermore, it's impossible to come up with a CF/SD card that would have direct sound feeding via the card bus to the inner hardware – the current card buses just don't support this kind of functionality. "

I have to disagree with this statement.

http://www.core-sound.com/pdaudio-cf.html

Core sound makes a SPDIF CF card that can record up to 24 bit 96khz. It's used by a lot of pros in the industry.

Thanks for the feedback!

Note the word 'direct'. The Core card digitizes the audio, and only after that sends it over the CF bus. This is certainly possible because it's simple data communication. However, (it seems) it's impossible to send over any non-pre-digitized (that is, analog) signal over the CF bus - it's just not have a direct, analog PIN (or PIN's) to communicate analogue data with the outside world. If it had, someone would already have come up with a CF-based GSM card/radio/TV receiver/etc card that is also able to route its sound through the PDA.

See http://www.pocketpcthoughts.com/forums/viewtopic.php?t=36151 for more info on this subject.

[Nat]

I see,

I think the approach to make the A/D conversion in the CF or SD card is the best one since the converters will probably be better than the one inside pdas.

I'd really like to see more devices like that.

Nat

[Len M.]

Note the word 'direct'. The Core card digitizes the audio, and only after that sends it over the CF bus.


This is not quite correct. PDAudio-CF accepts a digital audio signal -- it does not digitize.

PDAudio-CF accepts digital audio data streams up to 24-bit/192 KS/s, making it the smallest high-resolution digital audio recorder in the world. It records linear PCM with no data compression.

PDAudio is supported by Resco's Audio Recorder, Gidluck Mastering's Live2496 and Technica Del Arte's Luci.

[ipaqczar]

Nice article.

Screenshots would be helpful too I think.

I recently downloaded NoteM - and have had some problems with it. (ipaq 3950, 2002 OS).

It keeps going into playlist mode - and I can't change the settings for recording quality.

I am going to upgrade to WM2003 and try it with that.

[Menneisyys]

It keeps going into playlist mode

Even then when there're MP3's on your storage cards/in the main memory, and NoteM is also able to list them?

NoteM automatically switches to this mode if (and only if) it can't see any MP3 files.

BTW, I really recommend the WM2003 upgrade for the 39xx series - it'll fly after the upgrade. The PXA250 + PPC2k2 combo is dog-slow.

[Menneisyys]

This is not quite correct. PDAudio-CF accepts a digital audio signal -- it does not digitize.

Yes, indeed it's not the card itself (but the additional A/D converter) that digitizes the audio input. Thanks for pointing that I haven't been totally clear.

My point is still valid, however: only digital data can be sent through the CF bus, and not analogue.

[Menneisyys]

I've just added a section on NoteM / Resco stability ( http://www2.freeweb.hu/menneisyys/mp3/index.htm#_Toc97962191 ). I've also elaborated a bit on the bug in the SPX player module of Resco at the end of the http://www2.freeweb.hu/menneisyys/mp3/index.htm#_Toc97962198 section.