Getting Started with the Mash Tools
The best way to learn about the Mash tools is to just jump in and use them. Here's how to get started:
- Start up nsdr. It will ask for your name and phone number the first time you use nsdr.
- The nsdr program displays announcements of ongoing multicast sessions. The window will slowly fill with announcements as nsdr receives them from around the world.
- If nsdr does not receive any announcements after a while, your Internet service provider probably does not support multicast. You should email your provider and ask them if they support IP multicast.
- You can click on any session announcement to see more information about it. Look for announcements for "Places all over the world" or "NASA TV" and try clicking on one of them.
- In the "Program Info" window, you will see a list of applications. For now, you should only try to run listings that begin with vic or vat. The vic program displays multicast video. The vat program plays multicast audio. Click the Run button to the left of any vic or vat listings to start vic or vat.
- Experiment and have fun!
That's it for now.
We're still working on this section.
In the meantime, please join the
openmash-users mailing list if you
have any questions.
Running Open Mash Scripts
You can run Open Mash scripts using mash or smash. To run
a script that uses other Otcl classes you must set the environment variable
TCLCL_IMPORT_DIRS to point to the directory where the Open Mash code is
located. For example, if you downloaded the source tree to the directory
"/mnt/users/larry" you would define the following environment variable:
% setenv TCLCL_IMPORT_DIRS /mnt/users/larry/mash-code/mash
This directory contains the file "importTable" that provides the mapping
from Otcl classes to the file within which they are defined.
Open Mash Notes
contains further information on writing and running scripts.
In particular, the note
A Simple Open Mash Video
Encoding Application has an example of a simple encoding application
that will transmit a video stream to a multicast session.
Most Open Mash applications are written in Tcl and involve too many lines
to be stored in one file. An example is the Mbone Tool vic which
is composed of approximately 9,000 lines of Tcl decomposed into over 15 files.
You can browse this code using the LXR code browser - follow the link
vic source code.
It is located in the mash-code/tcl/vic directory in the source tree.
The Open Mash build process combines all of this code into one source file,
named "vic". You can run this code from it's location in the
source tree by defining TCLCL_IMPORT_DIRS or you can load all the source
by traversing the imports when you load the first script. Chema Gonzalez
describes a script for importing apps
here.
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