Broadcast2000 - The Production Studio

Matthias Nagorni

• Introduction
• Setting up the Application
• Recording Audio Data
• Editing Audio Data
• Selecting Regions and Zooming
• "Copy & Paste" and Other Editing Commands
• Playback and Save
• Automating Fade and Pan
• Adding Effects with the Plug-in Console

Introduction

In Broadcast2000, you can record and edit audio and video data. We will limit this section to audio data, but video data is processed in a similar way. If you are interested in video editing, that should be an easy task after reading this section. Detailed documentation on Broadcast2000 is available in the directory /usr/share/doc/packages/broadcast2000, in HTML format. The following section should simplify your initial encounter with this program.

Four windows will appear the first time you start up this application with bcast2000. Since we only want to deal with audio data, you can close the Video out window. This will leave you with the main window, the Console and the Levels windows. The main window already contains two empty audio tracks. To the left of the tracks, you will find one checkbox each for Play and Record. You can switch playback on or off with the Play checkbox. With the Record checkbox, you can specify whether a track is writable or not. This also applies to recording audio data as well as for all editing commands.

Please note: that the track data is only shown if the checkbox D has been activated. Click on Fit, once you have checked this box. This will cause the tracks to be redisplayed.

Broadcast2000 differs from many other editing applications in that the audio data is neither loaded to memory nor edited directly on the hard disk. Edits, crossfades and effects are saved to a text file in HTAL format ("hypertext audio language"). The source files used for a project remain unchanged. In this way, even very large files can be processed efficiently. Once the processing is complete, the results can be saved as a WAV file via the Render function.

Setting up the Application

The dialog box for setting up Broadcast2000 can be opened with Settings --> Preferences. A large variety of parameters can be entered here. Luckily you can simply use the preset values. If you are interested in what each parameter means, you can find this out in the installation.html file in the /usr/share/doc/packages/broadcast2000 directory.

Recording Audio Data

By clicking with the mouse on the red Record button in the tool bar, the Record dialog will open up. Here, you need to give a name for the file where your music data is to be saved. This is necessary because Broadcast2000 will immediately write the newly recorded data to the given file. The (preset) "WAV" format should be used as the file format. If you want to record 16-bit audio data, you will not need to make any further changes under Options. You must deactivate the checkbox Record video tracks, since video data cannot be recorded in "WAV" format. Click on the Do it button to close the settings. This will open up a new window, Recording. Now start the mixer gamix (see Section "gamix") in order to specify the recording source under Input MUX. If you then start the playback of the audio source, for testing purposes, you can set the input volume (Input Gain) with gamix, using the control display in the Recording window. Make sure that you don't turn this control up too high.

Under Recording mode you can select the method of recording. In the Untimed mode, the recording must be stopped manually, whilst in the Timed mode this is done automatically, after the set time has elapsed. With the Start over button, you can delete an unsuccessful recording attempt. If you are satisfied with the recording, you can save it with Save. An index file will then be added in /.bcast (extension .idx). If the option Paste output into project was activated in the Record dialog (the default setting), the recorded audio data will then be copied to the two audio tracks located inside the main window. Click on Fit in the main window to have the entire recording displayed.

Editing Audio Data

If you have been through the previous section, your audio tracks should already contain recorded music data. However, you can also load any files at all in WAV or MP3 format into the tracks. Use the File --> Load menus if you want to start a new project. In this case, existing data will be deleted. You can load data into an already existing project via the menu items File --> Append. Additional tracks will then be generated for this data. Extra (empty) tracks can be added either with the t key or via the menu items Audio --> Add track. You can create an entirely new project, with the menu items File --> New.

You can use the mouse to select certain regions directly. If you just want to adjust the left or right margins, press the Shift key as well at the same time. You can also enter the beginning and the length, or the end, of the desired region, in the entry fields at the bottom of the main window. The field to the left specifies the beginning. You can then either define the desired length in the middle field or, in the field to the right, where the region should end. You must press Enter for the entries to take effect.

The time specification highlighted in red shows the current position of the mouse cursor on the time axis. To the right of this is the display for the current "zoom". The length of the screen extract and the scale of amplitude display are shown here. You can change the "zoom" using the gray arrow buttons located in the tool bar. Here, X refers to time, Y refers to the amplitude and T refers to the track interval. If you click on Fit, the zoom will be automatically placed so that the currently selected region (or, if no region has been selected, the entire project) is set to the width of the window.

The Label button enables you to set the markings at the current position or at the edges of the selected region. The region contained in this window can then be selected by double-clicking on the time scale between the two marked positions. Edits are automatically marked by arrows on the time axis of each track. The regions between the edit marks can likewise be selected by double-clicking.

Broadcast2000 provides the customary basic editing functions such as Cut, Copy and Paste. All editing commands can only be applied to tracks for which the Record checkbox is activated. This mechanism is essential, since you can only select a region for all the tracks at the same time. If you want to copy a region from track 1 to track 3, for example, you must activate the Record checkbox for track 1 first and deactive this for all the others. Click on Copy and then click on the position where you want the data to be copied. Now enable the Record checkbox for track 3 and disable the Record checkbox for track 1. Following that, you can insert the data with Paste.

You can delete a selected region with Del or via Edit --> Clear. This will move the data located to the right of it to the left. If you want to prevent this data from being moved when deleting, you can use the Mute region function instead of Clear (m key). If you select a region and then call up Paste silence, the audio data will be moved to the right by an amount corresponding to its length, starting with the beginning of the region. The region will subsequently be filled with zeroes. Just try moving the edit marks yourself and see what happens. You can, of course, undo your experiments via Edit --> Undo at any time.

Playback and Save

Broadcast2000 leaves the source files used in a project unchanged. You can specify whether filenames should be displayed in the tracks via the menu items View --> Show titles. Initially, only information is saved about what you have processed, such as edits, crossfades and effects. During playback, the source files are then read from the hard disk and played according to this information. If you want to review a region more carefully (e.g. a cut), you can play the selected region in a single loop via Settings --> Loop Playback or via Shift L. The project will be saved as a text file in HTAL format via File --> Save or Save as. This file does not contain the actual audio data. This remains with the source files related to the project. You can view a list of these files via File --> Assets.

In order to also be able to play back the results of processing in a program other than Broadcast2000, you can save them as a WAV file, with File --> Render. If a region is selected, the output as well as the Render function will refer to this region. If the option Overwrite project with output is activated under Render, the project will be overwritten with the output. If you want to continue using the edited tracks in the project, you can generate two new tracks and check the Recordable checkbox just for these tracks.

In each track, several automation lines can be activated. These automation lines consist of straight sections which can be formed using the mouse. The most important line is the Fade line which represents an amplitude envelope. Activate this line with View --> Fade autos or with the 3 key. Then activate the Record checkbox for the track where you want to chart a Fade line. Now move the mouse pointer to the tracks time axis. You can mark a point on the Fade line with the left mouse button and then drag this in parallel to the time axis. The amplitude will then be shown simultaneously in decibels. You can define and move more points along the Fade line with the mouse. Even an arbitrary envelope for the volume can be mapped.

In most cases, you will want to define the same automation line for both stereo channels. Luckily, copy automation lines are easy to copy. For example, to copy a line from the left to the right channel, proceed as follows: Enable (only) the Record checkbox in the left channel. Press a to select the entire project and then Shift C, or Edit --> Copy Auto. Then enable the Record checkbox in the right channel (only) and insert the line with Shift V or Edit --> Paste Auto. You can enable or disable the automation for each track with the checkbox A.

In the View menu, you can activate further automation lines. Especially of interest here are the Pan autos with which you can influence the position of the track in the stereo panorama. You can use the Plugin autos in conjunction with the effect plug-ins of the console.

The console provides a real-time signal processor for each track. If your console should ever "disappear", you can always reopen it via Window --> Show Console at any time. Up to four different effects plug-ins can be used per track. During playback or "rendering", the audio signal will run through these plug-ins one after another, in the order they were set.

To add a plug-in, proceed as follows. Click on a Plugin button in the channel you require. A menu will open up with the menu items Attach, Send, Receive and Detach. If Send is activated, the plug-in will receive audio data from the tracks which are associated with it. If Receive is active, the plug-in will send the modified audio data back to the tracks. If you click on Attach, the plug-in dialog box will open up. Here, the channel and number of the plug-in will be shown. You can select a plug-in in the list Plugins (either by double-clicking or by selecting Attach and Do it). Choose the plug-in EQ Graphic, for instance. In this plug-in you can simply use the mouse to draw the frequency pattern of a filter. Once the playback has started, you can even hear your changes in real-time. Now you can activate the Spectrogram plug-in as a second plug-in. Here, you can see a visual display of the changes as they appear in the sound spectrum.
A tip for experts: The Window Size parameter appears in many plug-ins. This defines the size of the sub-area where signal processing operations such as convolution and Fourier transformation are carried out.

In most cases you will want to use the same plug-in for both stereo channels. Plug-ins can be shared by several channels. If you have activated EQ Graphic, for example, in the left channel, this plug-in will appear in the Shared plugins list in all the plug-in dialog boxes for the right channel. To remove a plug-in, click on Plugin --> Detach. Plug-ins labeled Automated (e.g. Pitch and Gain) can be controlled by a plug-in automation line. Apart from the plug-ins, there are still other elements in the console. With the Inv button, you can invert the signal. With Mute, you can silence a channel. To the left of the volume controls, you will see a black field. Here, you can define the position of the channel in the stereo panorama using the mouse. A two-dimensional button was chosen for this since Broadcast2000, in principle, also supports more than two output channels. In the default setting, all "uneven" channels are played in the left output channel and all "even" channels, in the right output channel. With the 0 button, you can reset the control display after an overdrive.