Subject: Re: [linux-audio-dev] Linux friendly, portable digital recording devices?
From: Jan Depner (eviltwin69_AT_cableone.net)
Date: Tue Dec 28 2004 - 00:38:40 EET
Neuros is very nice but a bit more expensive depending on how much
storage you need. It will record in mp3 or wav (up to 15/48KHz).
Jan
On Sun, 2004-12-26 at 16:19, Ian Howard wrote:
> Hey all,
>
> We are looking for some portable digital recording devices with the
> following criteria:
>
> - very small
> - durable
> - near $100 ($100-150)
> - usb compatible
> - linux + windows friendly
> - mic-in with a reasonable signal-to-noise ratio
> - descent quality recordings
> - battery powered
>
> We intend to distribute about 10 - 20 of these units to radio
> journalists in Mali, whom will use these devices to collect material for
> their programs which they can then edit in Audacity and broadcast on the
> air.
>
> We are looking at devices such as the iRiver 190T
>
> Any one have any experience with such devices, in particular using them
> with linux?
>
> Ian
>
>
>
>
>
> On Sun, 2004-12-26 at 12:06 -0500,
> linux-audio-dev-request_AT_music.columbia.edu wrote:
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> > Today's Topics:
> >
> > 1. Re: Tascam US428 Continued hangups (Spencer Russell)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Sun, 26 Dec 2004 02:09:21 -0800
> > From: Spencer Russell <Spencer.Russell_AT_oberlin.edu>
> > Subject: Re: [linux-audio-dev] Tascam US428 Continued hangups
> > To: linux-audio-dev_AT_music.columbia.edu
> > Message-ID: <20041226100921.GA12396_AT_slingshot>
> > Content-Type: text/plain; charset=us-ascii
> >
> > On Fri, Dec 24, 2004 at 12:05:07PM -0500, Rui Nuno Capela wrote:
> > >
> > > ...
> > > device. It was probably this very one that was aunting you before. After
> > > some attention and furious alsa-bugtracker exchange, Karten Wiese has been
> > > able to solve this, even tought he's got no OHCI hardware near him.
> > >
> >
> > I was watching that thread a little, because my symptoms were
> > very similar. Strangely, though, I have a UHCI based card, so I'm
> > not sure why I was seeing similar symtoms.
> >
> > > Then Karsten did it again. He crafted a special jackd alsa/usx2y backend
> > > which enabled the so-called raw-usb mode of operation. And it was just
> > > yesterday I have proposed the merge into the official alsa backend driver
> > > on the jackit-devel list. With this new experimental stuff, one can run
> > > jackd in realtime with pretty lowest-latency parameters, without aural
> > > artifacts (i.e. crackling). AFAICT this is a greatest breakthrough on the
> > > USB audio arena, so I would think twice about getting rid of your US428 ;)
> > >
> >
> > I'm having a bit of trouble with the usx2y backend to jackd. I
> > bastardized the jackd-us2xy rpm to make a nice deb file, but
> > jackd still says "unknown driver 'usx2y'". Even downloading and
> > compiling the source, and running it directly from the directory
> > it ws compiled into. And does it automatically use the rawusb
> > interface? What's the advantage of using the usx2y driver as
> > opposed to the alsa driver?
> >
> > > So my recipe goes like this:
> > >
> > > 1. Have REALTIME_PREEMPT on the kernel config.
> > >
> > > 2. Make sure you have loaded the latest snd-usb-usx2y>=0.8.7.1 (as of
> > > latest alsa-kernel cvs).
> > >
> > > 3. Tune the RT priorities (SCHED_FIFO) of the time-audio critical IRQ
> > > threads:
> > > 90 - timer (IRQ 0)
> > > 80 - rtc (IRQ 8)
> > > 70 - snd (or whatever your PCI soundcard will hook, usually IRQ 5)
> > > 60 - usb (ohci_hcd or uhici_hcd, usually IRQ 10)
> > > You should have schedutils installed (chrt) for this exercise.
> > >
> > > 4. Load the snd-usb-usx2y with the nrpacks parameter set for:
> > > a. high-stability: nrpacks=4
> > > b. low-latency: nrpacks=1
> > > Anyway, be advised that you can only run the forementioned "rawusb"
> > > mode if you set on this later one (modprobe snd-usb-usx2y nrpacks=1).
> > >
> > > Run your jackd command line (or qjackctl;) as usual, but given the above
> > > priority tunning, you should try e.g. jackd -R -P60 ...
> > >
> > Thanks a lot for this detailed info! I recompiled the newest
> > snd-usb-usx2y driver, but how do I tune RT priorities? I got the
> > schedutils package, but I'm having trouble finding details on how
> > to use chrt.
> >
> > Thanks again for the info.
> > -spencer
> >
> >
> > ------------------------------
> >
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> > linux-audio-dev_AT_music.columbia.edu
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> >
> >
> > End of linux-audio-dev Digest, Vol 15, Issue 46
> > ***********************************************
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