Posted by: Snowshoe
Aux in recording XM source - 06/03/2006 23:04
Been searching for this, Rio.org FAQ's say while this is theoretically possible it is unlikely to ever be implemented. I understand this but since then has anybody done it?
I'd like to record jokes I hear on the comedy channels on my XM satellite so I may remember them later & not sound like I'm remembering them as I tell it, which I am, but what a pain it is to listen to & tell.
I realize the player is a player and not a recorder & the drives would be required to be read-write. My guess is that monitoring the amount of HDD usage, disk space remaining, would be a factor as well. I wouldn't need a quality recording just clear enough to hear again later & undertand it. It wouldn't necessarily have to work when the XM is still playing which I understand would make it easier. Anything like that been done?
Posted by: tfabris
Re: Aux in recording XM source - 07/03/2006 05:39
Nope. As far as I know, nothing has been done on this front since that FAQ entry was written. You're welcome to be the first.
Posted by: Snowshoe
Re: Aux in recording XM source - 13/03/2006 12:02
That would be scary & damn near impossible for me.
Posted by: dcosta
Re: Aux in recording XM source - 05/06/2007 12:19
This would be amazing...
You are listening to a "live" source through the aux in
like the radio and you want to pause what you are hearing
like you normally do when listening to mp3 playback...
Just hit the "up" button...
Audio is muted and the empeg starts recording.....
Un pause and pick back up where you were...
if you come accross a commercial that was recorded while paused...
just fast forward a la tivo dvr.
I don't beleive that that the audio stream could be recorded in mp3 format,
compression of mp3 could be slower than real time.
but even a medium quailty wav audio format would be great.
I am in no way qulified to even know where to start on this software
but it sounds like a simple enough application.
you'd need some read write disk space...
oops, is there sufficient hardware on board an empeg to actually record an audio stream...?
<brain explodes>
any one else?
Posted by: mlord
Re: Aux in recording XM source - 05/06/2007 13:40
Buffering more than a minute or two of stuff would require the hard drive for buffer space,
which means it would then remain spun up for the duration, or at least until one's
listening catches up to "real time" again.
The drives will thus overheat (the cooling within the empeg is insufficient to handle
drives that spin continuously), so you'll want to combine your software with a fan
to keep things from melting down.
The cs4231a chip can sample from aux-in --> that's how the aux-in visuals are done.
Whether or not it can sample at sufficient quality for playback is another matter.
EDIT: An equally big question is, can it sample Aux-in while we play sound
from software, or is sampling of aux-in only possible when aux-in is being played out?
Cheers
Posted by: mlord
Re: Aux in recording XM source - 05/06/2007 16:28
We also have this note from Hugo, in the kernel source code:
Quote:
* The Crystal CS4231A is used for input from the microphone on the empeg
* board (rev6+). This is a soundblaster-like type thing, with 16-bit audio
* I/O and an ISA-style interface.
*
* It's hooked up to the outputs of the DSP (so we can sample anything the DSP
* is outputting - eg for doing visuals on the radio or aux inputs), to the
* mono microphone input, and to the aux inputs (allowing us to sample the aux
* in even when playing other things through the DSP).
Posted by: mlord
Re: Aux in recording XM source - 05/06/2007 16:32
Also from the source code, the kernel device driver for the cs4231a is currently
set up for a choice of three sample rates:
Quote:
static struct { short samplerate; char setup; } samplerates[]={
{ 11025, 0x0d },
{ 22050, 0x0c },
{ 29400, 0x0a },
{ 0, 0 } };
The usual rate used for visuals is 29.4KHz, Stereo, 16-bits/channel.
Not quite CD-Audio, but sufficiently good for high-quality radio in an automobile.
I don't know if there's a hardware crystal/clock limit that prevents even
better rates or not, but that should be simple enough to determine from
anyone with schematics, or from tracing signals on the PCB.
Cheers
Posted by: tfabris
Re: Aux in recording XM source - 05/06/2007 16:39
Well, if anyone is going to be able to successfully implement something like this, it would be you...
Posted by: FireFox31
Re: Aux in recording XM source - 05/06/2007 23:38
But if you hear the joke and decide that it's funny and you want to record it, the joke is past. Can you rewind XM radio to go back and grab it?
Still, sounds like an interesting project. There are tons of times that I hear a song I don't know on college radio and I'd like to record a clip or record the announcer saying the title/artist/label. Sure beats trying to type it into my Treo as I drive. (should have bought voice memo recording software for it by now...)