Rockbox Technical Forums

Support and General Use => Recording => Topic started by: Jim March on December 22, 2007, 02:49:17 AM

Title: Questions regarding E260 record behavior...
Post by: Jim March on December 22, 2007, 02:49:17 AM
My BIG question is, if one of these is recording and the battery runs dry, will it do a file save prior to shutdown?

This is a key issue for me.

Here's why: I'm a political activist who gets involved in some fairly hairy stuff.  I have my Sansa set up in a belt holster where it can't be seen as an active recorder and basically looks like a cellphone.

If very bad words are exchanged, and then I end up in a cell somewhere and get stripped of access to the Sansa, will it save whatever nastiness it took in, or will it just puke out and lose everything when the battery dies?

As a secondary thing, the record functionality needs some user interface tweaks.  A better-defined way of stopping and starting the recording is needed, without use of the shutdown button.  Hold it down too long and you lose what you were recording.

Personal audio recorders can revolutionize the whole concept of monitoring police and other official misconduct.  The improved recording control on the Rockbox helps :).
Title: Re: Questions regarding E260 record behavior...
Post by: Llorean on December 22, 2007, 10:28:23 AM
I've removed your link as it's really not related to Rockbox in any way.

Recording will be written every time the buffer is full, at a minimum. How often this is depends on what format you're recording in, but basically, at the very least if you're recording and the battery dies you should get everything except possibly the last 30 minutes or so of recording before battery death. It's possible the Sansa will get a bit more than that even. You are likely to have a corrupt file, but it should be fairly easy to recover.

As to the recording screen and use of the power button: Turning it off requires holding it for a couple seconds, stopping should require a mere tap. It was chosen for consistency between the Recording screen and the way the rest of the OS works.
Title: Re: Questions regarding E260 record behavior...
Post by: petur on December 22, 2007, 02:51:45 PM

Recording will be written every time the buffer is full, at a minimum. How often this is depends on what format you're recording in, but basically, at the very least if you're recording and the battery dies you should get everything except possibly the last 30 minutes or so of recording before battery death. It's possible the Sansa will get a bit more than that even. You are likely to have a corrupt file, but it should be fairly easy to recover.

When writing a WAV file (which I recommend) you'll have about two and a half minutes of buffered recording.
When power runs out, you will miss at maximum this buffer. But also the header will not be written, so you will need to import it in an audio editor (like audacity which is freeware) as RAW data. No big deal.
Title: Re: Questions regarding E260 record behavior...
Post by: rockxdude on January 10, 2008, 08:15:34 PM
Could someone please answer this question.

I have a Sansa e250 how long couuld I get a voice recording on it if I were using rockbox? If I added 2gb of microsd would that increase the time.


thanks for any help you can provide.

VF
Title: Re: Questions regarding E260 record behavior...
Post by: bascule on January 11, 2008, 03:39:21 AM
If using WAV format as recommended above, it takes up ~10MB per minute. AFAIK, the recording functionality won't use the MicroSD automatically, only if you choose it as the 'recording' directory.
Title: Re: Questions regarding E260 record behavior...
Post by: Roshambo on May 28, 2009, 10:45:38 PM
If using WAV format as recommended above, it takes up ~10MB per minute. AFAIK, the recording functionality won't use the MicroSD automatically, only if you choose it as the 'recording' directory.

How do you choose the MicroSD as the 'recording' directory?
Title: Re: Questions regarding E260 record behavior...
Post by: Chronon on May 28, 2009, 10:56:55 PM
You'll want to check the file browser's context menu (http://download.rockbox.org/manual/rockbox-sansae200/rockbox-buildch4.html#x7-420004.1.2)
Title: Re: Questions regarding E260 record behavior...
Post by: Roshambo on May 29, 2009, 12:44:21 AM
You'll want to check the file browser's context menu (http://download.rockbox.org/manual/rockbox-sansae200/rockbox-buildch4.html#x7-420004.1.2)

Thank you very much.  ;D
Title: Re: Questions regarding E260 record behavior...
Post by: LADave on May 17, 2013, 12:23:38 PM
I realize I'm late to the party. 

If you're just recording voices and ambient stuff, I'm curious why you are recording uncompressed PCM?  If capacity/hours is a concern, why not use a compressed format?  You probably don't need maximum HiFi, just a good enough sound track of what transpired.

Also there are thumb drive - size recorders on eBay for $10-15 that will record for 10-15 hours before the internal rechargeable runs.  Then software closes the file and powers down.  Much more concealable than anything that runs RockBox, and less heartache if it gets lost or confiscated.  Mine records in ADPCM IMA at 192,000 bits/second which is 4:1 compression.  But for battery run time, 8GB would be 96 hours!   I convert to PCM (.WAV) in the SOX utility program on a PC and it sounds pretty good.  Once in PCM it's completely editable.  This recorder clips at about 100 dB and there is a noise floor at about 40dB.

Here is a useful link about thumb drive recorders: http://www.chucklohr.com/usbaudiorecorder/   At http://www.chucklohr.com/808/index.shtml you will find coverage of videocams the size of key fobs that you might find useful as well.