-------- directBOX Reply ---------------
From: Vincent.Torri(a)math.u-bordeaux.fr
To : linux-audio-dev(a)music.columbia.edu
Date: 12.10.2003 12:30:38
Hello,
I am a newbie in the linux audio world and I have some stupid questions:
I want to wrote an ogg player with great quality playback. I've already
look at some other linux players and I've search this mailing list to
find some answers. It seems that two APIs are interesting: ALSA and Jack.
But i have not find some comparisons between these (and others) APIs
concerning the output quality (regardless the sound card).
Can someone give me some advice(s) about what API I should use
(comments, links, etc...) so that I could start working on it?
I would like to mention that I am not concerning about portability (only
linux platform) or easy programming, and I just want the best quality
output for this player.
I hope this is not the most stupid question of this mailing list :)
thank you
best regards
V.T.
------------
Well, ( like I understood it ) the quality of both are equal. If yes, you just have to know:
1.) jack ( http://jackit.sourceforge.net/ ) is easier to code, and the USER decide
which "options" are used, not your programme.
2.) alsa ( http://www.alsa-project.org/ ) is goes "deeper" into the hardware space,
your programme can decide which "options" are used and its sometimes harder
to code.
But this wasn't your question ;) .
jack does NOTHING with quality itsself, because jack is a user-space daemon other
apps connect to and send data to, which is then outputted via the currently used audio-driver.
And this is alsa ;)
( Or I think so - MY jack version ( Debian unstable ) does NOT have other possibilities,
my jack can only use alsa. Maybe this changed in newer versions! )
Hoped I helped
Sascha Retzki
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I'm searching for an audio API to parse a .wav file and show its waveform.
Someone knows something similar?
If not, someone could tell me how to do it by myself?
I mean if I open the file .wav and get one buffer at time, what I should do
to know its waveform?
Thank you,
J_Zar
Romanin Gianluca
Hello,
I am a newbie in the linux audio world and I have some stupid questions:
I want to wrote an ogg player with great quality playback. I've already
look at some other linux players and I've search this mailing list to
find some answers. It seems that two APIs are interesting: ALSA and Jack.
But i have not find some comparisons between these (and others) APIs
concerning the output quality (regardless the sound card).
Can someone give me some advice(s) about what API I should use
(comments, links, etc...) so that I could start working on it?
I would like to mention that I am not concerning about portability (only
linux platform) or easy programming, and I just want the best quality
output for this player.
I hope this is not the most stupid question of this mailing list :)
thank you
best regards
V.T.
Hi!
I bought a MIDI-keyboard a couple of days ago. It did not work correctly, and
I described my prob at lau. They told me that my ESS-Solo1 card is not able
to use MIDI ( under Linux or generally ?). Well, ok, I exchanged my card with my
fathers ( ES-1379 or simular ). Alsa supports it, I configured it and can listen to sounds.
If I start timidity in alsa mode ( "$ timidity -iA") and then attach my MIDI device with
timidiy via "$ acconnect 64 128", my system completely hangs!!! I must reboot via
the reset-button!! That's exactly the problem I had while I tried it ( the same way) with
my ESS-Solo1. Well, I am using Debian unstable, alsa version 0.9.0.beta12, have a
2.4.21-xfs kernel installed. Secondly, RG4-sequencer is NOT able to start MIDI and
I have no sound at all. Is it alsa's fault ? Is it mine ?
greez Sascha Retzki
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-------- directBOX Reply ---------------
From: magusofthedark(a)yahoo.com
To : linux-audio-dev(a)music.columbia.edu
Date: 11.10.2003 00:45:38
> >The prob. w/ portaudio is it abstracts to OSS, not
> >ALSA and I'd rather not take the least-common
> >denominator road.
>
> No. PortAudio abstracts to a callback model. Its
> closer to JACK than
> either OSS or ALSA. It isn't any closer to ALSA than
> it is to OSS.
I phrased that poorly. Say someone has ALSA and
doesn't have OSS compatibility. Would an app written
in portaudio work on their sys? If it doesn't, then
that's what I meant by that it doesn't abstract to
ALSA. If it does, then What I said was wrong, my bad.
--------
Like I understood portAudio's hp, portaudio is able to work with OSS.
Secondly, alsa is able to deal with OSS-apps because of an, well, OSS-emulation.
With other words OSS-applications are able to work with alsa, and they don't know
that they are working under alsa ;).
Ergo portAudio ( with it compatibility to OSS ) runs under OSS & ALSA and so
under Linux generally.
Sascha Retzki
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-------- directBOX Reply ---------------
From: paul(a)linuxaudiosystems.com
To : linux-audio-dev(a)music.columbia.edu
Date: 10.10.2003 17:37:43
>Hello !
>
>I've read somewhere that it is not possible that threads write different data to /
>dev/dsp.
>But how does Cheesetracker, for example, make it then?
i don't how cheesetracker does it, but it requires user-space
synchronization (e.g. pthread_mutex_(un)lock). with ALSA, you don't
need to to do this - any thread can write to the device at any
time. that's the theory, at least. in general, its probably a bad
design to be doing that, much like it is for GUI programming, where
its better to have a single thread mediate between the "device" and
the rest of the program.
------------------
But well, If I synthize ( ? spelling) two signals and want to send them at the same time
to the device, my first idea'd be:
1.) Open /dev/dsp, maybe O_NONBLOCK | O_WRONLY
2.) thread
3.) two threads calculate the both signals
4.) sync them
5.) two threads write their signals to /dev/dsp
6.) threads close
certainly some of this. I mean mp3blaster, for example, have several pids while playing audio streams, and it is basicly OSS-programming and not alsa.
Am I so wrong ? ;)
Sascha Retzki
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>OSS is dead. You should not be writing apps with OSS. If you want
>portability use PortAudio.
Yes, if heared many good stuff about PortAudio .... where is the homepage ?
Is it portable to NetBSD ( NetBSD is my "2nd OS" ;) )
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Hello !
I am interested how 2.6.X Linux kernel will handle OSS. I mean that alsa is the driver-layer for these kernels, are OSS-drivers/applications still supported ??
greez, Sascha Retzki
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Hi all,
I've had an interesting discussion with a professor and a distinguished
member of the electroacoustic music community regarding audio latencies
which made me realize that I did not understand the issue in its
entirety. Hence, I looked around the net in order to educate myself.
I soon stumbled across the following site:
http://old.lwn.net/1999/0916/a/latency.html
Admittedly, it's quite old but that, if anything speaks only in Linux's
favor in terms of its pro-audio readiness. At any rate, I was checking
out the benchmark data and was wondering as to how did this
person/software app get to the 0.73ms buffer fragment that is equal to
128bytes? In other words, what sampling rate was used?
128 bytes in 44100Hz sampling rate = 3ms
128 bytes in 88200Hz sampling rate = 1.45ms
128 bytes in 176400Hz sampling rate = 0.725ms (this one being obviously
closest, but at the same time, what kind of hardware supports this
sampling rate, especially in 1999 when this test was done?)
128 bytes in 192000Hz sampling rate = 0.3ms
So what gives? It seems like it is some kind of a 176k-ish sampling rate
that, AFAIK does not exist.
Furthermore, my question is what app was used to produce those
graphs/results and whether these latency tests take into account
hardware latencies (i.e. DSP converters, PCI->CPU->PCI->output etc.), in
other words, is this latency that is achievable with the following
setup:
Input->soundcard->cpu(with some kind of DSP)->soundcard->Output
Your help on this matter is greatly appreciated!
Ivica Ico Bukvic, composer & multimedia sculptor
http://meowing.ccm.uc.edu/~ico
Hi,
yesterday was the opening of the "Southtyrol game",
one of the worlds largest hand carved pinball style game machines.
(length: 11 metres, weight: 2.6 tons, 16 audio speakers)
It is an interesting combination of art, electronics and audio powered
by Linux. The game is located in Southtyrol - Italy in a museum
dedicated to tourism.
The audio part was implemented by me.
I created a webpage with a description and some movie clips
that demonstrate how the game works.
http://www.linuxdesktop.it/benno/southtyrolgame/
Thanks to all Linux developers in particular the LADers that made
audio under Linux a viable solution !
comments ?
PS: would such a story qualify for slashdot ?
Just try to submit it if you want ;-)
cheers,
Benno
http://linuxsampler.sourceforge.net
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