26 Aug
2005
26 Aug
'05
11:47 p.m.
Hi all,
I'm pretty new to the world of audio on linux, so please excuse the
"newbeeness" of my question. :-)
I'm a in the process of making a police/EMS/fire radio recorder. At
first, I tought of doing a program similar to ScanRec(1) from the
windows world -- that is not record when the sound is below a certain
threshold. This could easily be done with ecasound's -ge parameter.
However, I started thinking and found that it would be better to have a
different file for each segment. For example, if there is
- 45 seconds of speech, followed by
- 3 minutes of silence, followed by
- 2 minutes of speech
I would get two files, one 45 seconds long and one 2 minutes long.
Does such a program allready exists, and if not, what would be the
best/easiest way of doing it?
1: http://www.davee.com/scanrec/
Thanks a lot,
GFK's
--
Guillaume Filion, ing. jr
Logidac Tech., Beaumont, Québec, Canada - http://logidac.com/
PGP Key and more: http://guillaume.filion.org/
27 Aug
27 Aug
3:36 a.m.
not that i know of. i'd love something like this too (as long as it was
a jack client!). i almost wrote a jack client to do this a while ago. if
this was done as a jack client, it would be pretty easy to modify the
existing jackrec (i think that's the one) example client. jackrec works
roughly like this:
- opens a file to record to
- process gets n samples, which it copies to a record ringbuffer
- a worker thread sleeps until it has got some samples from process. it
wakes up and writes them to the file
- repeat the last 2 steps until done, then close the file and exit
here's how i think the client you describe would have to be designed.
instead recording all the time, your write thread would not write until
the signal level crossed a certain level threshold. to track this you
would need an envelope follower with a fast attack and a long release on
the signal. when the signal level exceeds the threshold, you start
writing to the already opened file. when it falls back down below the
threshold you stop writing and close the file. if your program was
really smart, it would already have a second file open ready to write to
so that if the signal rose above the threshold before it was able to
close the old file and open a new one, it would be able to write to the
new file without interruption. if it were less smart it would
immediately open the new file after closing the old one, and with a big
enough ringbuffer that may be ok.
good luck!
ian
On Fri, 2005-08-26 at 21:47 -0400, Guillaume Filion wrote:
Hi all,
I'm pretty new to the world of audio on linux, so please excuse the
"newbeeness" of my question. :-)
I'm a in the process of making a police/EMS/fire radio recorder. At
first, I tought of doing a program similar to ScanRec(1) from the
windows world -- that is not record when the sound is below a certain
threshold. This could easily be done with ecasound's -ge parameter.
However, I started thinking and found that it would be better to have a
different file for each segment. For example, if there is
- 45 seconds of speech, followed by
- 3 minutes of silence, followed by
- 2 minutes of speech
I would get two files, one 45 seconds long and one 2 minutes long.
Does such a program allready exists, and if not, what would be the
best/easiest way of doing it?
1: http://www.davee.com/scanrec/
Thanks a lot,
GFK's
--
ian esten <deviant(a)custard.org>
28 Aug
28 Aug
10:54 p.m.
New subject: [linux-audio-dev] ALSA MIDI logger? (Was: Radio Scanner Recorder)
On Saturday 27 August 2005 03.47, Guillaume Filion wrote:
[...]
(...)that is not record when the sound is below a
certain threshold.
This could easily be done with ecasound's -ge parameter.
However, I started thinking and found that it would be better to
have a different file for each segment. For example, if there is
- 45 seconds of speech, followed by
- 3 minutes of silence, followed by
- 2 minutes of speech
I would get two files, one 45 seconds long and one 2 minutes long.
Is there anything like this, but for MIDI, out there?
I'd like something that runs in the background (I'd probably start it
up automatically with the system), subscribing to any ALSA MIDI
inputs that might be of interest, automatically recording all events,
and saving each "burst of activity" as a separate .mid file.
One would probably want to make sure that each .mid gets a header that
restores the CC state at the time the recording started, and some
comments about the ALSA sequencer routing and connected clients might
come in handy sometimes. None of that is really required, though.
This strikes me as something that should be relatively easy to do,
though I'd rather not hack it from scratch if there's any reasonably
nice code lying around somewhere.
//David Olofson - Programmer, Composer, Open Source Advocate
.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,... |
`-----------------------------------> http://audiality.org -'
--- http://olofson.net --- http://www.reologica.se ---
29 Aug
29 Aug
7:58 a.m.
New subject: [linux-audio-dev] ALSA MIDI logger? (Was: Radio Scanner Recorder)
On Mon, 2005-08-29 at 02:55 +0200, David Olofson wrote:
On Saturday 27 August 2005 03.47, Guillaume Filion
wrote:
[...]
For the SMF part, you probably already have arecordmidi installed on
your system. Ctrl-C (SIGQUIT) at end of file to terminate.
Perhaps modifying it slightly to treat start/stop commands as begin/end
of file would be useful. Your appliction would then be a midithru,
inserting midi-stop after a certain amount of inactivity and midi-start
when you start playing again.
(...)that is not record when the sound is below a
certain threshold.
This could easily be done with ecasound's -ge parameter.
However, I started thinking and found that it would be better to
have a different file for each segment. For example, if there is
- 45 seconds of speech, followed by
- 3 minutes of silence, followed by
- 2 minutes of speech
I would get two files, one 45 seconds long and one 2 minutes long.
Is there anything like this, but for MIDI, out there?
I'd like something that runs in the background (I'd probably start it
up automatically with the system), subscribing to any ALSA MIDI
inputs that might be of interest, automatically recording all events,
and saving each "burst of activity" as a separate .mid file.
One would probably want to make sure that each .mid gets a header that
restores the CC state at the time the recording started, and some
comments about the ALSA sequencer routing and connected clients might
come in handy sometimes. None of that is really required, though.
This strikes me as something that should be relatively easy to do,
though I'd rather not hack it from scratch if there's any reasonably
nice code lying around somewhere.
//David Olofson - Programmer, Composer, Open Source Advocate
.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,... |
`-----------------------------------> http://audiality.org -'
--- http://olofson.net --- http://www.reologica.se ---
--
9:20 a.m.
New subject: [linux-audio-dev] ALSA MIDI logger? (Was: Radio Scanner Recorder)
Is there anything like this, but for MIDI, out there?
I'd like something that runs in the background (I'd probably start it
up automatically with the system), subscribing to any ALSA MIDI
inputs that might be of interest, automatically recording all events,
and saving each "burst of activity" as a separate .mid file.
One would probably want to make sure that each .mid gets a header
that restores the CC state at the time the recording started, and
some comments about the ALSA sequencer routing and connected clients
might come in handy sometimes. None of that is really required,
though.
This strikes me as something that should be relatively easy to do,
though I'd rather not hack it from scratch if there's any reasonably
nice code lying around somewhere.
maybe RtMidi is a piece of code which can help you easily doing such a
tool:
http://www.music.mcgill.ca/~gary/rtmidi/
Best regards
ce
31 Aug
31 Aug
5:57 p.m.
New subject: [linux-audio-dev] ALSA MIDI logger? (Was: Radio Scanner Recorder)
On Monday 29 August 2005 11.58, Jens M Andreasen wrote:
[...]
For the SMF part, you probably already have
arecordmidi installed on
your system. Ctrl-C (SIGQUIT) at end of file to terminate.
Doh! I did have a feeling that 90% of the code I need was right under
my nose... :-D
Thanks! :-)
Perhaps modifying it slightly to treat start/stop
commands as
begin/end of file would be useful. Your appliction would then be a
midithru, inserting midi-stop after a certain amount of inactivity
and midi-start when you start playing again.
Or maybe just add the complete "auto split" feature to arecordmidi...?
If I'm going to hack it anyway, it might be easier to just do the
whole job there, as the basic ALSA "framework", build scripts and
stuff is already there.
//David Olofson - Programmer, Composer, Open Source Advocate
.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,... |
`-----------------------------------> http://audiality.org -'
--- http://olofson.net --- http://www.reologica.se ---
1 Sep
1 Sep
3:05 a.m.
New subject: [linux-audio-dev] ALSA MIDI logger? (Was: Radio Scanner Recorder)
On Wed, 2005-08-31 at 21:58 +0200, David Olofson wrote:
On Monday 29 August 2005 11.58, Jens M Andreasen
wrote:
[...]
I noticed that stdin is unused ...
A thread that reads commands and new filenames from stdin would be
convenient in conjunction with popen()
For the SMF part, you probably already have
arecordmidi installed on
your system. Ctrl-C (SIGQUIT) at end of file to terminate.
Doh! I did have a feeling that 90% of the code I need was right under
my nose... :-D
Thanks! :-)
Perhaps modifying it slightly to treat start/stop
commands as
begin/end of file would be useful. Your appliction would then be a
midithru, inserting midi-stop after a certain amount of inactivity
and midi-start when you start playing again.
Or maybe just add the complete "auto split" feature to arecordmidi...?
If I'm going to hack it anyway, it might be easier to just do the
whole job there, as the basic ALSA "framework", build scripts and
stuff is already there.
//David Olofson - Programmer, Composer, Open Source Advocate
.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,... |
`-----------------------------------> http://audiality.org -'
--- http://olofson.net --- http://www.reologica.se ---
--
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days inactive
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days old
linux-audio-dev@lists.linuxaudio.org
6 comments
5 participants
participants (5)
-
Christoph Eckert -
David Olofson -
Guillaume Filion -
ian esten -
Jens M Andreasen