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jAudio 1.0 Online Help

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Manipulating Audio For Processing

Adding Recordings

The most obvious method for adding recordings is to click the "Add Recordings" button. This button pops up a file daialog window. Files chosen will be added to the recordings table.

A second way of adding a recording is to select "synthesize" from the Recordings menu. This menu allows one to save the generated file to disk. Additionally, the file saved is automatically added to the Recordings table.

A third way of adding recordings is to select the "Record from mic" from the Recordings menu. This window allows onme to record audio and then save this recorded audio to file. This file is then added to the Recordings table.


Removing Recordings

To remove recordings from the Recordings panel, select the entries in the recording table that one wishes to remove and either press the "Remove Recordings" button in the main window or select "Remove Recordings" from the Recordings menu.


Validate Recordings

From the Recordings menu is a checkbox for validating Recordings. If this checkbox is selected then all recordings that are added are first completely loaded into memory in order to verify that the recording is a valid recording file. Deselecting this box will save time and memory when the recording is first loaded but may result in bad recordings being discovered in the middle of analysis.


Storing Samples

From the Recordings menu there is a checkbox for storing samples of recordings. This checkbox controls whether or not the samples referred to by the file are directly loaded into memory or are left to reference by file. Note that this feature has a similar effect to the validate checkbox except that the samples are retained after the file has been read.


Editing a Recording

To edit a recording, select a file in the recordings table and select "Edit Recordings..." from the Recordings menu. All changes are finalized if and only if the window is dismissed using the OK button. Several different methods of editing and viweing the file are presented.

Changing the file format

The "Choose possible format" button allows one to select a sampling rate along with several other features. These settings are not applied, however, until this window is dismissed using the "ok" button and the "Change to Possible Format" button is clicked. This can be undone with the "Restore" button

Applying Gain

The "Apply Gain" button takes a float value from the text dialog box immediately to its right and interprets it as a double. All samples in the file are multiplied by this value as soon as the "Gain" button is pressed. This can be undone with the "Restore" button.

Normalizing file

This immediately scales the file such that the maximum value is 1.0 by applying the appropriate gain. This can be undone with the "Restore" button.

Mix Down to One Channel

This mixes any stereo or higher recording into a mono recording. This can undone with the "Restore" button.

Play

This button plays the file to the default sound output device

Stop

Stops any playback that may be taking place.

Restore

Restores the file to its original state.

View Samples

This provides a mechanism for viewing all the samples of a recording. Note This takes a very long time to produce for all but the shortest files. The system is unresponsive in the meanwhile.

Plot Samples

This provides a mechanism for viewing the samples in a graph. Note This takes a significant amount of time. Large recordings will cause the system to appear to hang while preparing the display.

Plot Spectrum

This provides a mechanism for viewing the harmonic spectrum of the entire recording. Note This takes a significant amount of time to produce. Large files will cause the system to appear to hang while preparing the display.

Recording from a Microphone

jAudio has the ability to record new audio to be saved and added to the recordings table. This can accessed by choosing the "Record from Microphone" menu item from the "recording" menu. This displays a new window which has several components.

  • Setting the final encoding
  • Displaying the encoding of already recorded audio
  • Choosing what file type the audio should have
  • Recording of audio
  • play back previously recorded audio
  • saving or discarding recorded audio

Setting the final encoding

The "Change Encoding Format" allows one to alter the properties ofthe audio recorded audio. The new settings will be applied to the audio as it is save (after pressing the "Save" button).


Displaying the encoding of already recorded audio

If audio has already been recorded, the "Display Current Encoding" button will display a pop up window with showing the current format of the recorded audio.


Choosing what file type the audio should have

This combo box contains all available output formats that are available for file writing.


Recording of Audio

The "Record" button immediately starts recording. If no recording devices are available for recording, an error message is displayed. The recording continues until the "Stop Recording" button is pressed. Starting a new Recording without first saving the audio results in the discarding of the original recording.


Play Last Recording

The "Play Last Recording starts playback of the last recording. This playback can be stopped by pressing the "Stop Playback" at any time.


Saving or discarding recorded audio

The "Save" button saves the recorded audio, sapplying any changes specified in the "Change Encoding Format" window. If no recording has been made a dialog box permits the canceling of the save. If the "Cancel" button is pressed, all recordings are discarded immediately and the window closed.

View Recording Info

This displays all the meta information about a given recording, including such information as its sample rate and number of channels. To access this information, first select a recording in the recording table and then choose "View Info" from the "Recordings" menu.