Understanding The Signal Path For Sound In Os X

Hello,

GetLength, which returns the number of samples in the sound. GetSamplingRate, which returns the number of samples per second for the sound. Play, which plays the sound provided as input. BlockingPlay, which plays the sound provided as input and makes sure that. For a new path to be added to PATH environment variable in MacOS just create a new file under /etc/paths.d directory and add write path to be set in the file. Restart the terminal. Restart the terminal.


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I have a seemingly basic question, I hope.


  • First off, I am running the latest OSX (prior to Mavericks) on the latest Mac. Plenty of Hard Drive Space.
  • I am using a Focusrite Scarlett 212 audio interface.


When I plug my guitar or bass into the Audio interface and play I can see that Logic Pro X is receiving the signal however I am not able to get any sound. I have tried both the Line and Instrument setting on the Audio Interface, although I know it should be set to Instrument. Neither works.I have tried the Direct Moniter on/off switch on the Audio Interface and again, no luck.

I have toggled the input monitoring button in Logic Pro X within the track I am getting the signal on but that hasn't worked either. Both the track levels and Master levels register the sound coming in yet I have no sound.


Any ideas what I am missing/ doing wrong/ f*cking up?

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I appreciate any assistance that anyone can offer.


Best regards,


-Alex

iMac, iOS 6.1.4

Signal

Posted on


10.5: Use a built-in command line audio player | 28 comments | Create New Account
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Cool, I have been Hijacking the alert sound with a script in 10.4, to run headless sound, but could not do this in 10.5 due to the alert sound time limit. Thanks for the heads up on this.
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mh

Is there a way to play the audio without having to keep the terminal window open?
On a related note, could I run it off an applescript and have the applescript quit without the audio stopping?
Thanks,
MacTipper

Just add an & after the command and it will run in the background, thus allowing you to close the terminal window (or even quit terminal entirely) without affecting playback.
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Aluminum iMac 20' 2.4 GHz/3GB/300GB HD

That only somewhat works. I can continue working in that same terminal window, however, if I close it, I get a warning saying that I'm going to terminate running processes (login, bash, afplay)
My command:
afplay /Users/Shared/iTunes/iTunes Music/Aaron Shust/Whispered and Shouted/01 Long Live the King.mp3 &

Don't worry that you're doing something wrong. You're correct. Using & puts it in the background of the shell, but if you kill the shell, you kill that application as well.
(Applications don't run without a controller of some manner.)
You have two options, and both may be a bit more involved than you want to be.
One is that you can use the 'nohup' command to continue command execution even if the shell goes away. Or you can learn how to use the 'screen' command.
nohup will continue command execution until completion (or failure, either way a program exit), and then it'll go away.
screen is a 'terminal multiplexer', it allows you to turn one terminal into many all self contained. It serves an excellent second purpose that if you're doing something (say, ssh'ed into a remote server) and your connection goes away, everything you were doing inside screen continues to run, or everything you have done remains there in context until you reconnect to the server and resume screen.
This of course works locally. Be forewarned this is a VERY extreme example. If you're running screen, and terminal crashes, nothing happens to screen. It's all still there to reconnect to when you re-open Terminal and reconnect to it.
The only thing screen doesn't do is survive a reboot (go figure).
It'll take a little bit of learning to get used to it (the man page is VERY big), but I absolutely swear by screen.

There's an easier way to close a terminal window (which is not the preferred way to end the shell inside it---similar to using 'force quit' to end safari instead of the quit menu command) without OS X whining or killing the programs you've started:
Instead of ending a command with '&', end it with '& disown' (no quotes, of course).
Note: This will work for essentially *any* program, but if there are semi-colons (;) in the line you typed, you are running more than one program and simply adding ' & disown' to the end of the line may not be sufficient to get the behavior you want.
I am sure the OP gave up on this page long ago, but in case future readers who stumble on this page are daunted by your suggestions (valid though they are), I though this very simple fix would be useful.

This is a little complicated - the full details are far too involved to go into right here.
However, the bottom line is that you can control whether a shell's subprocesses (bash = your shell) are terminated, when the shell is terminated.
By default, I don't think bash itself terminates its backgrounded children, when you exit bash (by typing control-D or exit).
That is, it does not terminate its children on my system, but I've long forgotten if that was something I configured myself, or the default behavior. I think it's default behaviour though - pretty sure.
However, from just testing now, it appears that if you click the red 'close' button, Terminal itself terminates bash AND its children for you.
So the simple solution might be to close your shell by typing 'exit' or control-D instead of clicking the close button.
What actually happens when you click the red 'close' button is that the system sends a TERM (exit) signal to the shell - and when bash receives a TERM signal, it sends a TERM to all of its children before it exits itself.
However when you terminate bash by typing 'exit' or control-D, it doesn't send a TERM to its children.
nohup and screen are not needed.
ksh also does not terminate its children by default when exiting, and nohup is needed.
Whether bash does or not is definitely configurable.
There's a lot I'm not explaining here but as you can see it would run into pages and pages and pages if I tried to explain it all here now!
If you read a few man pages (particularly of bash) and do a bit of testing you should be able to get it to do what you want.

There is a simpler way to run a program in the background and detach it from the controlling terminal without using nohup. Just do this.

The parentheses request the creation of a subshell which becomes the parent process for the program you run. You can verify this works as follows.

You'll see something like this.

(Ignore the grep sleep which is the command you just ran.) A minute later, the same ps/grep will reveal that the program has terminated (and so has the parent subshell).

That does not work
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mh

Does for me, exactly as I described. If it doesn't for you, then you are doing something different. I started the music with the command as I described, and the proceeded to completely quit terminal. The music happily continued playing. It works.
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Aluminum iMac 20' 2.4 GHz/3GB/300GB HD

No I am not doing anything different? .

But what does work is,

I can then close the window or quit terminal.

Thanks

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mh

it does work. when i run it, i get the following on my screen:
bash-3.2$ 2008-10-03 12:57:02.956 afplay[524:10b] Error loading /Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder: dlopen(/Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder, 262): no suitable image found. Did find:
/Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder: mach-o, but wrong architecture
2008-10-03 12:57:02.958 afplay[524:10b] Error loading /Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder: dlopen(/Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder, 262): no suitable image found. Did find:
/Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder: mach-o, but wrong architecture
2008-10-03 12:57:02.960 afplay[524:10b] Error loading /Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder: dlopen(/Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder, 262): no suitable image found. Did find:
/Library/QuickTime/DivX 6 Decoder.component/Contents/MacOS/DivX 6 Decoder: mach-o, but wrong architecture
hit enter to return to your prompt.
type 'exit'
the music should continue.

This means that your library is for the wrong architecture. You can find the file on another mac that has the right one and copy it over (I had to do that for one of my iMacs, which had the OS pre-installed by Apple. The Mac Pro, where I installed the OS form the DVDs had the right version).
Alternatively, you could find the file on the OS X installer DVD, but you will need a package manager/explorer for that.

Here's an applescript way...
set soundPath to choose file
do shell script 'afplay ' & quoted form of POSIX path of soundPath & ' > /dev/null 2>&1 &'

Awesome! Thanks regulus!

i'll try edit file hosts by type: sudo /Applications/TextEdit.app/Contents/MacOS/TextEdit /etc/hosts
have a error: [IMG]http://banchothue.com/open-file-host-error.png [/IMG]
please help me!
thank off all!

If only this would work with a stream URL... Anyone know of a command line alternative for that?

Mplayer svn checkout http://www.mplayerhq.hu/
svn://svn.mplayerhq.hu/mplayer/trunk mplayer
That baby does it all from the command line

Does not work with protected audio files from iTunes, but QuickTime Player is able to play them.

You might want to try another (third-party) command-line utility called play, which can play every audio file supported by QuickTime, incl. protected AAC files (as long as you machine is authorised).
'Is there a way to play the audio without having to keep the terminal window open?'
You can by putting an '&' at the end of the file. FOR EXAMPLE:
afplay /Users/Moo/Music/4 Tom Sawyer.mp3 &
You will then see this: [1] (random number) 63955
The song will then play in the background. You can stop by typing the word kill and the number it returns FOR EXAMPLE:
kill 63955
or you can more simply type in
killall afplay
to stop everything without having to worry about the number!
Hope that helps!
~Moo
For

You can also chain several songs together by repeating the afplay command after a semicolon:
afplay music.mp3 &; afplay sound.mp3 &
etc..
I'm not a terminal geek so i had to fart around with this a bit to get it, but if I simply copy a file in the Finder then paste it after the afplay command (or simply drag it into the terminal) the path formatting will stay intact. So, that's probably the easiest thing to do for most people if they are getting file not found errors.

Sorry, putting an ampersand & after each track means that all tracks will play in parallel. You should put one ampersand at the end.
afplay a.mp3 b.mp3 c.mp3 &

Even more interesting to me is 'afconvert', a front end to the various codecs supported by QuickTime.

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That is awesome. Got some converting to do.

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This is awesome! I am deployed to Iraq and when I want to mess with my wife & son I ssh home and make the computer 'say' stuff. Now I can play them music in the AM!! YES!!! Thank you Mac OS X Hints, once again you are the *censored* of the walk! OK, I cannot say rooster's other names, so its censored, there by ruining my SNL reference.

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There is also the 'afinfo' command - gives you all the details on a sound file.
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T. Farrell

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Can I pause and resume an audio file using afplay ?