From 4d84d14ac1aa13958eaa2971b03f7f929a519105 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?IOhannes=20m=20zm=C3=B6lnig?= Date: Fri, 8 Feb 2008 13:00:32 +0000 Subject: reorganized svn path=/trunk/; revision=9400 --- desiredata/doc/1.manual/x3.htm | 790 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 790 insertions(+) create mode 100644 desiredata/doc/1.manual/x3.htm (limited to 'desiredata/doc/1.manual/x3.htm') diff --git a/desiredata/doc/1.manual/x3.htm b/desiredata/doc/1.manual/x3.htm new file mode 100644 index 00000000..9bc0f537 --- /dev/null +++ b/desiredata/doc/1.manual/x3.htm @@ -0,0 +1,790 @@ + + + + + Pd Documentation 3 + + + + + + + +

Pd Documentation chapter 3: Getting Pd to run

+ +

+ back to table of contents +

+

+ +

Pd runs under Irix, Microsoft Windows, Linux, and MacOS 10.2 (Jaguar). +How to get Pd up and running depends on your operating system, +but the overall strategy is the same. +You must first get and install it, and +then untangle whatever problems arise in handling audio and MIDI input +and output, and finally get Pd to meet its real-time obligations reliably. + +

Installation instructions are platform-specfic; the following four +sections +will describe what to do for various operating systems you might have. +In case of trouble also consult the Pd mailing list archive on + + http://iem.kug.ac.at/mailinglists/pd-list/ +, which often has late-breaking news about configuration problems and solutions. +The rest of this section describes how to get audio and MIDI to work. + +

3.1. Audio and MIDI

+ +

+To test audio and MIDI, start Pd and select "test Audio and MIDI" from the +"Media" menu. You should see a window like this: + +

+ test tone patch +

+ +

First, try to get Pd to play a sine wave over your speakers. The "TEST +TONE" control at top left turns this on and off. Normally, all the output +channels are turned on so that when you turn the tone on (to a soft -40 dB or a +louder -20 dB) you should get output on the first six of your output channels. +(If you have fewer than six output channnels open, the extra +channels aren't played; and if you have more, this particular patch won't +use them.) + +

If there's anything wrong, the most likely outcome is that you will hear +nothing at all. This could be for any of at least three reasons: Pd might +have failed to open the audio device; the audio card's output volume might +be set to zero; or your audio system might not be set to amplify the computer +output. + +

The number boxes labeled "AUDIO INPUT" show the levels of incoming +audio, in dB, with 100 being maximum. (Incoming signals may clip at +RMS levels below 100; for instance, a sinusoid clips at about 97 dB.) +Any DC present in the input (such as you get with cheap audio hardware) +will show up as level unless you turn on the "input hipass" toggle +at right; then the DC component is filtered out before metering. + +

To test the quality of audio input and output, turn on "monitor" +(also at right) which causes the inputs to be played to the outputs at +unit gain. You should hear a faithful, non-distored copy of whatever is +sent through the patch. + +

It is easy to get two copies of Pd running by accident; on most machines +only one at a time may be inputting and outputting sound. (Some copy of Pd +might have audio or MIDI devices open and prevent the copy you're trying to use +from getting access to them.) Having extra +copies of Pd around will also eat CPU cycles uselessly. + +

+You may be interested in getting only audio output or audio input, or +you may need both to run simultaneously. By default, Pd will try to run +both, but if you don't need either input or output, you may find that Pd +runs more reliably, or at least more efficiently, with the unused direction +turned off. This may be specified in Pd's command line flags or using the +"audio settings" dialog panel. + +

+Depending on your application you will have a more or less stringent latency +requirement. Ideally, when any input (audio, MIDI, keyboard, network) is +available, the outputs (in particular the audio output) should react instantly. +In real life, it is necessary to buffer the audio inputs and outputs, trying +always to keep some number of milliseconds ahead of real time to prepare for the +inevitable occasions where the CPU runs off to service some different task +from Pd. How small this latency can be chosen depends on your OS and your +audio driver. + +

TIP: If Pd starts up but you get distortion or glitches in the audio +output, this could be either because the "audio I/O buffer" isn't big enough, +or else because the CPU load of the patch you're running is too great for the +machine you have, or else because the ADC and DAC are out of sync or even at +different sample rates. To test for the first possibility, try increasing the +audio latency in the command line or the "audio settings" dialog (but see also +under your OS below.) For the second, start up your favorite performance +monitor program; and for the third, try starting Pd up with ADCs disabled. + +

In addition to the "test audio and MIDI" patch, the "Media" menu +contains items for controlling audio and MIDI settings. The first two +items, "Audio on" and "Audio off", open or close the audio devices and +start or stop Pd's audio computation. + +

If there is a choice of +audio API to make, the Media menu will display them. (On Linux, they are +OSS, ALSA, and Portaudio; on Windows, you get MMIO and ASIO). More information +about the APIs appears in the sections below. + +

Next is the "Audio settings..." menu item, which opens a dialog like this: + +

+ audio settings dialog +

+ +The exact choices you get depend on the operating system and API. The sample +rate controls both audio output and input. The audio throughput delay is +the nominal amount of time, in milliseconds, that a sound coming into the +audio input will be delayed if it is copied through Pd straight to the +output. Naturally you would like this to be as small as possible, but, +depending on OS, API, and even the specific choice of audio hardware, there +will be a limit to how small you can make this. You can typically get +10 msec on linux (and lower still if you use special tricks), 30 msec on Mac +OSX, and 60 msec on Windows (but note that there might be ways that a +patient Windows user can reduce this). + +

Next you get a choice of input and output device. If you want to open +more than one, hit "use multiple devices" and you'll be allowed up to 4 +in and 4 out. Each audio device is 2 channels by default, but you may +specify more if your hardware supports it. + +Other parameters may be tweaked using the command line; see under + preferences and startup options . + +

MIDI
+ + The "channel message" midi objects in Pd +such as notein or pgmout will take channels 1-16 to mean the first open MIDI +port, 17-32 the second one, and so on. The midiin, sysexin, midiout objects +give you a separate inlet to specify which of the open MIDI port numbers +you want. + +

System exclusive MIDI message input and output is theoretically supported +in version 0.37 but does not work correctly on windows, even in 0.38. + + +

3.2. Installing Pd in Microsoft Windows

+ +

Pd should work under any version of Windows since 95. You can download as +a self-extracting archive (a ".exe" file). Run this and select a destination +directory when prompted, such as "\pd" or "Program Files\pd". + +

If for example you put Pd in "C:Program Files\pd", the executable program +will be "C:Program Files\pd\bin\pd". You can simply adjust your path to +include C:\pd\bin and then invoke "pd" in a command prompt window. You can also +make a shortcut to the executable program (left-click on it and drag to the +desktop, for example.) + +

Pd requires "TCP/IP networking" to be turned on. This doesn't mean you +have to be on a real network, but simply that Pd actually consists of two +programs that make a "network link" (locally) to intercommunicate. + +

Audio in Microsoft Windows

+ +

+You can ask for a list of audio and MIDI devices by typing +"pd -listdev"; you can then specify which audio and MIDI device to use. +Type "pd -help" (or make any mistake) to get the syntax for specifying +which device to use. You can modify the Pd shortcut (or batch file) to +set these, or else use the "startup" dialog (file menu) to specify +startup arguments. + +

+Alternatively, (and especially when just starting out) you can experiment +with different audio configurations using the "audio settings" +item in the Media menu. + +

+You can list and +choose MIDI devices in the same way as audio; note that, by default, MIDI +input is disabled in Windows (because it's possible to hang up some MIDI +devices if Pd exits unexpectedly). + +

+MIDI timing is very poor if you are using simultaneous audio input and output; +if you suppress either audio input or output things will improve somewhat under +NT; you can apparently get the jitter down to ~40 msec. On W95 performance is +simply terrible. W98, with either audio input or output suppressed, offers +fairly good MIDI timing (~5 msec jitter). The "first edition" used to crash +occasionally; this might be fixed in the "second edition". + +

ASIO

+ +

As of version 0.35 Pd supports ASIO. Invoke Pd as "pd -asio" and, if +needed, specify "-sounddev" (etc.) flags to specify which device (see +"the Pd command line" below.) You can also specify a "-blocksize" different +from the default (256 samples) and "-audiobuf" in milliseconds. Pd will +round this down to a power of two buffers, each of "-blocksize" in sample +frames. + +

3.3. Installing Pd in Linux

+ +

What to do depends on which flavor of Linux you are running (e.g., Debian +or Red Hat). The instructions here should work for Pd 0.33 and up regardless of +your situation. (If not, you can read the Pd mailing list archives for +recent problems; if you have found a new problem you're welcome to post it +to the list.) + +

If you're running RedHat or Mandrake you might want to use RPM to install +Pd. For other linux distributions, download the "tar.gz" version and compile +Pd. + +

Getting Pd as an RPM

+ +

Download Pd, perhaps from + + http://www.crca.ucsd.edu/~msp/software.html , +to a file such as "pd-0.33-0.i386.rpm". +Open a "shell" window, cd to +the directory containing the file, and type the command, +

+    rpm -i pd-0.33-0.i386.rpm
+
+ +

(substituting the real file name.) Then you should be able to type "pd" +to a shell and watch the Pd main window appear. + +

Getting Pd as a .tar.gz

+ +

Before you start, you might want to check that you have the resources Pd +needs. The main things you need are the C compiler, X windows (including +the X development package for Pd to link against) and TK. If you're running +Redhat or Mandrake 7.x or up, I think these are all present by default. +The RedHat X client developer "RPM" package is called XFree86-devel. + +

+Download Pd, perhaps from + + http://www.crca.ucsd.edu/~msp/software.html , +to file such as "pd-linux-033.tar.gz". Open a "shell" +window, cd to +the directory containing the file, and type the command, +

+    tar xzf pd-linux-033.tar.gz
+
+

which creates a directory named "pd". I do this from my home directory. +Next, compile it. "CD" to pd and read the INSTALL.txt, or else just cd +to "pd/src" and type + +

+
./configure +
make depend +
make +

+ +

You can pass flags to "configure" to customize your compilation: + +

+    To enable debugging (and losing code optimization) add "--enable-debug".
+    To use Portaudio version 19 (experimental), add "--enable-portaudio".
+    To put Pd in /usr/bin instead of /usr/local/bin, add "--prefix=/bin".
+
+ +Alsa and Jack support should auto-configure, but "--enable-alsa" od +"--enable-jack" will force their inclusion. + +

After "make", just type "~/pd/bin/pd" to run pd. + +

Alternatively, as superuser, you can run "make install" after "make depend" +and then anyone on your system can just type "pd" to run it. + +

Testing audio and MIDI.

+ +

+Next try audio. We want to know whether audio output works, whether audio +input works, and whether they work simultaneously. First run "aumix" (or +any newer audio mixer app) to +check audio input and output gains and learn which input (mic; line; +etc.) is "recording". +Then test audio output by running +

+    pd -noadc
+
+

and selecting "test audio and MIDI" from the "Media" menu. You should see +a patch. Turn on the test tone and listen. Do the usual where's-the-signal +business. + +

+Then quit Pd and test audio input via +

+    pd -nodac
+
+

Re-open the test patch and hit "meter"; look at the levels. 100 dB is a +hard clip; arrange gains so that the input signal tops out around 80 or 90, +but no higher. + +

Now see if your audio driver can do full duplex by typing "pd" with no +flags. If you see error messages involving /dev/dsp or /dev/dsp2, you're +probably not able to run audio in and out at the same time. If on the other +hand there's no complaint, and if the audio test patch does what you want, you +might wish to experiment with the "-audiobuffer" flag to see what values of +audio latency your audio system can handle. + +

Audio hardware in Linux

+ +

+Be forewarned: installing and testing audio and MIDI drivers in Linux can take +days or weeks. There apears to be no single place where you can get detailed +information on Linux audio. One good source of information lives at: + +http://www.djcj.org/LAU/guide/index.php . + +

+There are two widely-used driver sets, called "OSS" and "ALSA". OSS is +included in the standard Linux kernels since version 2.2. However, for some +audio cards you can find newer versions than are included in the kernel +releases. You can get ALSA from + + + http://www.alsa-project.org/ . + +

ALSA is able to emulate OSS, so that you can usually run Pd using the +default "OSS" settings even if it's actually ALSA that's running. +ALSA is newer, hence less stable and harder to use, than OSS. +Installing ALSA can be tricky and/or confusing. + +

By default, Pd uses OSS. If you are running ALSA, Pd will use ALSA's OSS +emulation. To make Pd use ALSA "natively", i.e., the way ALSA is designed +to be used, include the "-alsa" flag in the command line or bang on the "media" +menu items. + +

You can add ALSA devices by name on the Pd command line: +

+    pd -alsaadd loupgarou
+
+instructs Pd to offer the 'loupgarou' audio device in the Audio Settings panel. + +

Experiences with particular soudcards

+ +

+Here are some of my own experiences with sound cards so far. See +also the Pd mailing list archives. + +

RME 9652 (Hammerfall)
+ +

This is the best sound card out there; it costs around $500 and has 3 ADAT +I/O ports and one SPDIF. There is a "baby hammerfall" also, which I think is +the "9632." DO NOT CONFUSE THE 9652/9632 WITH OTHER RME BOARDS WHICH MIGHT +NOT WORK WITH PD. + +

The easiest way to use +Hammerfall boards in Pd is via ALSA and jack; but you can use ALSA alone: +

+    pd -alsa -channels 26
+
+works for me. If you don't specify the number of channels correctly Pd crashes. + +
MIDIMAN
+ +

Midiman sells PCI devices (delta 44, 66, 1010, and 1010LT) +with between 4 and 10 channels in and out, for +which there are ALSA drivers. These are also very good, and they are a +bit cheaper than Hammerfalls. The driver name is "ice1712". + +

Alsa provides an "envy24control" program (in "utils". You should run +this and check that your ice1712's sync source is internal if you have no +SPDIF input, or "SPDIF" if you do. I think the default is now "internal" +but don't take it for granted... + +

warning about i810/i815 drivers...
+ +

As of RedHat 7.0, motherboards with native i810 audio systems didn't work in +full duplex (they crashed linux). Either run Pd -noadc or else (better) +install ALSA. This ought to be fixed by now... + +

3.4. Installing Pd in Macintosh OSX

+ +

Pd version 0.35 and up support Macintosh OSX. You need the OSX Jaguar +distribution (10.2) or later. + +

To install Pd you can always just download the sources and compile them +yourself, or (easier) just download the Mac binary from the download page: + + +http://crca.ucsd.edu/~msp/software.html. + +This is in the form of a compressed Tar archive; just click on it and the Max +will extract the Pd application. Open this and you should be running. + +

The package by Hans-Christoph Steiner, on + + +http://at.or.at/hans/pd/installers.html, + +has many updates and extensions +which are not included in the original Pd distribution. Download this and +follow the (simple) instructions found there. +

+ +

To install on OSX from source:

+ +

+Whether you've downloaded the source or the "package" you can +always compile Pd for yourself, whether to make your own improvements, or +possibly so that you can get the newest version before it shows up compiled for +Mac OS X. + +

To be able to compile Pd, you must have installed Tcl/Tk +specifically in +/Applications/Wish Shell.app +and /Library/Frameworks/Tk.framework and /Library/Frameworks/Tcl.framework. + +

First download and install TK for OSX. I get it from: + +http://tcltkaqua.sourceforge.net/. + + +

Then, just as for linux, just unload pd-whatever.tar.gz into a directory +such as ~/pd-0.36-0, cd to pd-0.36-0/src, type "./configure" +and "make". Then type ~/pd-0.36-0/bin/pd to a shell and enjoy! + +

If you wish you can put a line such as, + +

+    alias pd ~/pd/bin/pd
+
+ +

in the file, ~/.tcshrc, so that you can later just type "pd" to a shell. +(The +shell only reads the ~/.tcshrc file on startup, so this won't take effect in +any existing shells unless you specially type +

+    source ~/.tcshrc
+
+

to them.) + +

Follow the general directions above for testing audio and/or MIDI +as needed. + +

To get MIDI working, you have to do the Mac OSX magic to get a USB +MIDI interface installed. I've seen this done with Midisport devices and +I think you just download the OSX driver and follow directions. + +

3.5. Installing Pd in IRIX (SGI machines)

+ +

(NOTE: as of release 0.35 I haven't had an IRIX machine to compile +Pd on. Soeren Bovbjerg has kindly compiled 0.35 and 0.36 for IRIX; +you can find these at + http://www.cvmt.dk/~sb/ .) + +

Download Pd, which will be a "tar.Z" file. You can unpack this by +typing "zcat [name].tar.Z | tar xf -" to a shell. This creates a directory +named "pd". + +

+Starting with release 0.25, Pd should come in "n32" and "o32" versions. +"o32" is the default and will run on IRIX 5.x and up. "n32" runs faster, +but only on 6.x and up. Also, "externs" have to be updated for n32. The +"pd" executable (bin/pd in the distribution) is a symbolic link to either +"pd-o32" or "pd-n32." + +

NOTE: "externs" appear to be broken in the N32 version... I'm not sure +how long this has been true. If you want to use external objects, you have +to use the O32 version. + +

+If for example you put Pd in ~, the executable program +will be ~/pd/bin/pd. The program looks at its command line to +figure out where it is, so it's best to invoke Pd by its full pathname. +You should always invoke Pd from a Unix shell because many important +messages appear on the standard error. + +

+The simplest way to invoke Pd is to +make an alias in your ".cshrc" file (assuming you use the "c" shell) such as: +

+
+
+    alias pd ~/pd/bin/pd
+
+
+

(assuming your Pd distribution landed in ~, for example). + +

+Pd will open the "default" audio input and output devices, without regard +for whether they are in sync or not. This will be bad if they aren't; use +the "-noadc" or "-nodac" flag to disable either the input or output. Pd is +supposed to handle up to 8 channels of audio in and/or out. (But at least +one user had to recompile Pd on his Onyx to get 8 channels working.) + +

+As to MIDI, Pd simply attempts to open all available MIDI devices for input and +output, which is probably very bad on anything more recent than my Indy. If +any MIDI ports fail to open either for input or output, all MIDI is disabled. + +

Pd has not been fixed to request real-time priority from Irix; it will +compete with all other processes on your machine for CPU time. + +

Audio and MIDI in IRIX

+ +

+Pd takes command line arguments to set the number of input and output channels +and the sample rate. These don't affect the SGI's audio settings, which you +have to set separately using the "audio panel." Pd does detect the audio +sample rate if you don't specify one on the command line. + +

+On SGI machines, you have to work to get MIDI running. Before you start Pd, verify +that least one MIDI port is configured open. Pd opens the FIRST MIDI port +that's open. You might want to get rid of the "software" MIDI port if you're +running 6.x. On Indys, the usual practice is to open serial port number 2 +because some systems configure port 1 as "console" by default. You can use the +GUI if you want, or else just type +

+
+    startmidi -d /dev/ttyd2
+
+
+ +

to get port 2 speaking MIDI, and + +

+
+    stopmidi
+
+
+ +

to stop it. You can test whether MIDI is configured by typing, + +

+
+    ps -dafe | grep midi
+
+
+ +

and looking for "startmidi" processes. + +

+It's a good idea to connect your serial port to your MIDI interface before +typing the "startmidi" command, not afterward, at least in 5.x. We use the +Opcode Studio 3 interface but in principle any Mac-compatible one should work. + +

+The O2 apparently has RS232 ports, not RS422. I think SGI's web site says +something about how to deal with this. + +

3.6. Preferences and startup options

+ +

Pd's behavior may be customized to instruct it where to find files, which +audio devices to open, what font size to use, and so on. Most of +these may also be changed using the various dialogs you can open from Pd's +menus. Others take effect only when Pd starts up; some of these appear +on the ``startup" dialog and some of them, too cranky to put in a GUI, must +be typed as command line arguments . + +

In addition to the Audio and MIDI settings (see + Audio and MIDI ), you can customize font size (from the +``edit" menu), directories to search for files (see + How Pd searches for files ), and additional startup +parameters described below. + +

All of these settings may be saved automatically between Pd sessions. +It is also possible to specify settings directly via the command +line . (A third mechanism, using configuration files, is deprecated and +isn't described here.) The Pd command line is described in the next +section. Command line settings, if given, each override the corresponding +setting that was saved from Pd. + +

The startup settings (i.e., those that take effect only when Pd is started) +are controlled using the ``startup..." dialog from the File menu. The +dialog appears as follows: + +

+ startup dialog +

+ +The slots at top each specify a binary ``library" for Pd to load on startup. +These may be for Gem, pdp, zexy, iemlib, cyclone, and so on. Typically, a +single binary object (an ``extern") is left for Pd to load automatically; +startup library loading is appropriate for collections of many objects +specified by a single binary library. + +

The ``defeat real-time scheduling" contol, if enabled, makes Pd run without +its usual effort to become a real-time process (whatever this means in the +operating system you are using.) In Unix, Pd must usually be setuid to allow +real-time scheduling at all. + +

The ``startup flags" allow you to add to Pd's command line on startup. This +is specified as described below, except that the initial word, ``pd", is +understood. For example, putting ``-rt" in this field sets real-time +scheduling; ``-sleepgrain 1" sets the sleep grain to 1 (see under MIDI below), +and typing "-rt -sleepgrain 1" does both. + +

You may save the current settings for future Pd sessions with the +``save all settings" button; this saves not only the path but all other +settings as well. + +

Command line arguments
+ +

Pd may be run as a "command line" program from your "terminal emulator," +"shell," or "MSDOS prompt." In Windows, if Pd is started using a "shortcut" +it is also run from a command line which you can edit using the ``properties" +dialog for the shortcut. In any operating system, Pd can be called from a +script (called a batch file on Windows or a shell script +on OSX or unix). The command line is just a line of text, which should be +of the form: + +

+
+    pd [options] [patches to open]
+
+
+ +

although you may have to specify a path (such as "~/pd/bin/pd" or +"C:\program files\pd\bin\pd") so your command interpreter can find +Pd. Possible options include: + +

+
+audio configuration flags:
+-r <n>           -- specify sample rate
+-audioindev ...  -- sound in device list; e.g., "2,1" for second and first
+-audiooutdev ... -- sound out device list, same as above 
+-audiodev ...    -- specify both -audioindev and -audiooutdev together
+-inchannels ...  -- number of audio in channels (by device, like "2" or "16,8")
+-outchannels ... -- number of audio out channels (by device)
+-channels ...    -- specify both input and output channels
+-audiobuf <n>    -- specify size of audio I/O buffer in msec
+-blocksize <n>   -- specify audio I/O block size in sample frames
+-sleepgrain <n>  -- specify number of milliseconds to sleep when idle
+-nodac           -- suppress audio output
+-noadc           -- suppress audio input
+-noaudio         -- suppress audio input and output (-nosound is synonym) 
+-listdev         -- list audio and MIDI devices
+
+(linux specific audio:)
+-frags <n>       -- specify number of audio fragments (defeats audiobuf)
+-fragsize <n>    -- specify log of fragment size ('blocksize' is better...)
+-oss            -- use ALSA audio drivers
+-alsa           -- use ALSA audio drivers
+-pa             -- use portaudio (experimental version 19)
+-alsadev <n>     ----- obsolete: use -audiodev
+-32bit             ---- (probably obsolete) -- use 32 bit OSS extension
+
+(Windows specific audio:)
+-mmio           -- use MMIO drivers and API
+-asio           -- use ASIO drivers and API
+
+MIDI configuration flags:
+-midiindev ...   -- midi in device list; e.g., "1,3" for first and third
+-midioutdev ...  -- midi out device list, same format
+-mididev ...     -- specify -midioutdev and -midiindev together
+-nomidiin        -- suppress MIDI input
+-nomidiout       -- suppress MIDI output
+-nomidi          -- suppress MIDI input and output
+
+general flags:
+-path <path>     -- add to file search path
+-nostdpath       -- don't search standard ("extra") directory
+-stdpath         -- search standard directory (true by default)
+-helppath <path> -- add to help search path
+-open <file>     -- open file(s) on startup
+-lib <file>      -- load object library(s)
+-font <n>        -- specify default font size in points
+-verbose         -- extra printout on startup and when searching for files
+-version         -- don't run Pd; just print out which version it is
+-d <n>           -- specify debug level
+-noloadbang      -- suppress all loadbangs
+-stderr          -- send printout to standard error instead of GUI
+-nogui           -- suppress starting the GUI
+-guiport <n>     -- connect to pre-existing GUI over port 'n'
+-guicmd "cmd..." -- substitute another GUI program (e.g., rsh)
+-send "msg..."   -- send a message at startup (after patches are loaded)
+-rt or -realtime -- use real-time priority (needs root privilege)
+-nrt             -- don't use real-time priority
+
+
+ +

Here are some details on some of the audio, MIDI, and scheduler options (but +see also the next section on file management.) + +

multiple devices.

+ +

You can specify multiple MIDI input and output devices. For example, +"pd -midiindev 3 -midioutdev 4,2" asks for the third MIDI input device and the +fourth and second MIDI output device. + +

Audio device selection is similar, except that you can also specify +channels by device: "-audioindev 1,3 -inchannels 2,8" will try to open device 1 +(2 channels) and device 3 (8 channels.) + +

sample rate.

+ +

The sample rate controls Pd's logical sample rate which need not be that of +the audio input and output devices. If Pd's sample rate is wrong, time will +flow at the wrong rate and synthetic sounds will be transposed. If the output +and input devices are running at different rates, Pd will constantly drop frames +to re-sync them, which will sound bad. You can disable input or output if this +is a problem. + +

audio buffer size and block size

+ +

You can specify an audio buffer size in milliseconds, typically between 10 and +300, depending on how responsive your OS and drivers are. If this is set too +low there will be audio I/O errors ("data late"). The higher the value is, +on the other hand, the more throughput delay you will hear from the audio +and/or control inputs (MIDI, GUI) and the audio coming out. + +

You can also specify the audio block size in sample frames. This is 64 by +default (except for MMIO for which it's 256), and may be 64, 128, or 256. + +

MIDI and sleepgrain

+ +

In Linux, if you +ask for "pd -midioutdev 1" for instance, you get /dev/midi0 or /dev/midi00 +(or even /dev/midi). "-midioutdev 45" would be /dev/midi44. In NT, device +number 0 is the "MIDI mapper", which is the default MIDI device you selected +from the control panel; counting from one, the device numbers are card +numbers as listed by "pd -listdev." + +

The "sleepgrain" controls how long (in milliseconds) Pd sleeps between +periods of computation. This is normally the audio buffer divided by 4, but +no less than 0.1 and no more than 5. On most OSes, ingoing and outgoing MIDI +is quantized to this value, so if you care about MIDI timing, reduce this to 1 +or less. + +

3.7. How Pd searches for files

+ +

Pd has a search path feature; you specify the path on the command line +using the "-path" option. Paths may contain any number of files. If you +specify several files in a single "-path" option they're separated by colons +in unix or semicolons in NT. + +

You can see and edit the path while Pd is running using the "path..." +item in the "File" menu: + +

+ startup dialog +

+ +

The path must be correctly set before you load +a patch or it may fail to find abstractions, etc., that are needed to +construct the patch. When Pd searches for an abstraction or an +"extern" it uses the path to try to find the necessary file. The "read" +messages to qlists and arrays (aka tables) do this too. + +

If ``use standard extensions" is enabled, the usual ``extras" directory +is also searched. This contains standard external objects like ``expr" and +``fiddle", and perhaps much more depending on the distribution of Pd +you're using. + +

You may save the current settings for future Pd sessions with the +``save all settings" button; this saves not only the path but all other +settings as well. + +

Path entries may be relative to the patch directory; for instance, +if your path has an item, "../sound", and your patch is in "my stuff/all mine", +then Pd will look in "my stuff/sound". Spaces should be OK in the path to +the patch, but not in the path entry (../sound) itself. This is useful if +you have a patch and supporting files (even a supporting snapshot of pd) +that you want to distribute or carry around together. + +

Regardless of path, Pd should look first in the directory containing +the patch before searching down the path. Pd does not automatically look +in the current directory however; to enable that, include ``." in +the path. The ``extra" directory, if enabled, is searched last. + +

Filenames in Pd are always separated by (unix-style) forward slashes, even +if you're on Windows (which uses backslashes). This is so that patches can be +ported more easily between operating systems. On the other hand, if you +specify a filename on the command line (as in "pd -path c:\pdlib") the file +separator should agree with the operating system.
+ +

If a filename specified in a patch has any "/" characters in it, the "path" +is not used; thus, "../sounds/sample1.wav" causes Pd only to look relative to +the directory containing the patch. You may also invoke externs that way. + +

As of version 0.35, there may be spaces in the path to Pd itself; also, +the "openpanel" and "savepanel" objects can handle spaces. Spaces in the +path should work as of version 0.38. + + + + + -- cgit v1.2.1