Tobi Audio Insertion and Editing
1. Audio Representation
2. Generating Audio from Text
3.1. Altering the Playback Speed
3.2. Auto play
4. Audio Insertion
4.1. Importing Audio Files
4.2. Recording Audio
4.2.1. Audio Monitoring
4.2.2. Basic Recording
4.2.3. Recording with Warm-up Playback
4.2.4. Continuous Recording
4.2.5. Recording in Overwrite Mode
4.2.6. Tape-like Recording
4.2.7. Narrator View
4.2.8. Session Counter
5. Audio Editing
5.1. Marking Cursor Position
5.2. Audio Selection
5.3. Previewing Audio
5.4. Step Back and Forward
5.5. Commands for Navigating Within or Among Waveforms
5.6. Cut, Copy, and Paste
5.7. Splitting Audio
5.8. Deleting Audio
5.9. Editing Audio Externally
6. Audio Processing
7. Audio Settings
Audio is represented as waveforms in Tobi and is exhibited in the Audio Editor pane. At one point of time, only the waveforms corresponding to the items selected in Document Pane are displayed. If the selected item contains sub-items, their waveforms will be displayed too. The figure below illustrates how waveforms are displayed in Tobi.
Time is displayed along x-axis and amplitude along y-axis. A red line moving horizontally across the waveform is the audio cursor, which notifies the current playback position.
The waveforms exhibited in the Audio Editor pane can be scaled along x-axis using the audio zoom commands, or zoomed in/out using the global magnification commands.
Generating Audio from Text
You can generate synthetic voice equivalent for the text of the document in the following ways:
- To generate audio for the entire document, click Audio->TTS audio (Entire document) on the menu or press Shift+Ctrl+G.
- To generate audio for the selected item (section, paragraph, sentence, etc), click Audio->TTS audio (Selected text) on the menu, press Ctrl+G, or use the Generate TTS button of the Audio toolbar.
Tobi generates audio using the synthetic voices selected in the Audio Settings. If you have mapped different XML elements to different synthetic voices using the configuration file, the audio content for each XML element will be generated using the respective voice.
The playback command of Tobi enables you to hear audio corresponding to the selection as well as the entire audio content of your project. To listen to the audio content of the selected item, click Audio->Playback->Play on the menu or press Space. Alternatively, you can click on the Play button of the Audio toolbar.
By default, the audio cursor moves to the beginning of the waveform once the entire content contained in the selection is played. You can disable this behaviour and instruct Tobi to keep the audio cursor at the end by turning on the application preference Audio_DisableAutoJumpToBegin_AtEndOfPlayback.
To play audio of the project continually, click Audio->Playback->Play auto advance on the menu, press Shift+Ctrl+Alt+Space or use the Play auto advance button of the Audio toolbar. Once you execute this command, Tobi will keep on moving to the next item automatically while playing its audio. Because of this reason, the Play auto advance command is very useful for inspecting book contents.
You can pause the playback by pressing Space,.
Altering the Playback Speed
You can increase or decrease the speed of playback by using the following commands:
- To increase playback speed, click Audio->Playback->Increase playback rate on the menu or press Ctrl+Up Arrow.
- To decrease playback speed, click Audio->Playback->Decrease playback rate on the menu or press Ctrl+Down Arrow.
- To bring the playback speed to default, click Audio->Playback->Reset playback rate on the menu or press Ctrl+0.
The Auto play option instructs Tobi to play audio of the item to which user navigates. This option can be turned off or on using the Status bar, which also informs its current state. To toggle the state of the Auto play option, simply click on the Auto play segment of the Status bar. Keyboard users should do the following:
- Go to the Status bar using F4.
- Navigate to the Auto play segment using Tab repeatedly.
- Press Enter to activate or deactivate it.
Audio can be placed in Tobi by two methods:
- Import audio file and split it into smaller chunks that map to their text equivalent.
- Record audio directly in Tobi
The sections that follow elaborate on both the workflows.
Please note that you may find some text in the document, which is not intended to be synchronized directly with audio. If you want to associate some audio content with it, you must navigate to the parent element (by mouse-click or using the shortcut Shift+Ctrl+Comma) and place the relevant audio there. The commands like navigation, Split, and Stop recording and continue will automatically skip these elements and select the next element to which audio can be associated.
Importing Audio Files
You can import pre-recorded audio content in Tobi by following the steps listed below:
- Click Audio->Import audio file(s) on the menu bar, press Shift+Ctrl+I, or click the Import audio file button of the Audio toolbar.
- A dialog box opens that lets you browse for WAV/MP3/MP4/AAC files.
- Choose the required file(s) and click Open.
Tobi will import the file(s) in your project. Where the audio content from the files will be copied depends on the current position or selection as listed below:
- If an audio selection has been marked, it will be replaced with the audio content from the file.
- Otherwise, the imported content will be inserted at the position of the audio cursor.
Tobi provides an extensive functionality for recording audio content directly. The sections that follow explicate various methods and also throw light on related functions and supporting tools.
Before recording for the first time in a session, it is recommended to perform audio monitoring to check microphone sound levels, which should be neither too low making audio inaudible, nor too high that may result in clipping and distortion. To perform audio monitoring, click Audio->Recording->Start monitoring on the menu or press Ctrl+M. If the focus is on waveforms or Status bar, you can press a single key M to start monitoring.
The peak meter in the extreme right of the Audio Editor pane enables you to monitor audio graphically and check for overloads. As soon as you give the command to monitor or record audio, it will start displaying the sound levels. If the sound level reaches the red portion, it indicates that the volume should be reduced.
You can initiate recording by any of the following methods:
- Click Audio->Recording->Start recording on the menu.
- Press Ctrl+R.
- Use the Start Recording button of the Audio toolbar.
Tobi will start recording from the input device at a location determined by the following rules, listed in the order of their priority:
- If you have marked an audio selection, it will be replaced. Consequently, the audio waveform will first contain audio prior to the beginning of the selection, followed by newly recorded content, and finally, audio after the end of the audio selection.
- Otherwise, audio will be recorded at the current play head position, which can be the beginning of the waveform, at the end of the waveform, or anywhere in between. In the last case, the audio content prior and subsequent to the cursor position will still surround the newly recorded content. Please note that you can initiate the Record command during playback also, which will result in insertion of audio at the position where recording was invoked.
To stop recording, do any of the following:
- Press Ctrl+R again.
- Press Ctrl+Space, or Esc.
- If the focus is on waveforms or Status bar, press a single key shortcut Space.
Recording with Warm-up Playback
This alternate of basic recording can be used by narrators to tune their voice as per previous content so that there is no irregularity in the recorded audio. To make use of this feature, click on the Preview before recording segment of the Status bar. Clicking on this segment will result in activating or deactivating this feature.
If you turn it on, Tobi will play a small portion of audio immediately preceding the marked cursor position or beginning of audio selection each time you hit the Record command. A decrementing time counter will also be displayed over the waveform notifying the time remaining to start recording. As soon as the playback reaches the cursor position or the time counter starts showing 0, the Record command will be invoked.
In this way, Tobi supports punch recording; whereby you can select the audio to be replaced with new recording and hit the Record command to do the needful.
The fastest way to record the contents of a book in Tobi is to keep narrating the contents and moving to the next item by just a push of a button. The white round button in the Audio toolbar, called Stop recording and Continue, enables you to move to the next item after you have narrated the contents for the current item; thereafter, you can continue recording audio for next item and so on. You may also use the shortcut key combination, Shift+Ctrl+R, to achieve the same functionality. Or if the focus is on waveforms or Status bar, you can use a single key R. Other alternative is to use the menu item Audio->Recording->Stop recording and Continue, which may not be preferred once you get the hang of the keyboard shortcut. After the day’s job, you can place a document mark where you stopped and restart from there the next day, directly moving to the bookmarked item via the Marks tab of the Navigation pane.
There is only one case when Tobi will interrupt this workflow, and that is, when some audio content already exists in the next item . As it would be undesirable to remove or alter already recorded content, the choice of taking decision about the audio is left with the users.
The recording flow can be further improved by toggling the granularity of the document from fine to coarse. Since giving the Stop recording and continue command for every sentence or word may hinder the document narration, Tobi enables you to reorganize the document’s text to be synchronized with the coarse granularity that would bundle the entire paragraph into one item of the Document pane. Thereafter, you can record the contents of one paragraph at a time. But in this case, you should use the split command afterwards for mapping the recorded audio to its text equivalent.
Recording in Overwrite Mode
Tobi also enables you to overwrite the audio content with the audio being recorded. To enable this recording mode, click Record overwrite button on the Status Bar or check the checkbox Audio_Record_OverwriteFollowingAudio in the application preferences of Tobi.
Tobi will replace the content from the audio cursor to the end of the waveform by the audio being recorded. If some part of the waveform had been selected, Tobi will replace the selection only.
Tobi enables tape-like recording behaviour for narrators. It can be activated by turning on two application preferences, Audio_DisableAfterRecordSelection and Audio_Record_OverwriteFollowingAudio.
If the preference Audio_DisableAfterRecordSelection is turned on, Tobi places the audio cursor at the end of newly recorded audio instead of selecting it, and the latter preference enables recording in overwrite mode. When both preferences are active, Tobi replicates fluent tape-like recording. Both the preferences can be turned on or off using the Status Bar or application preferences.
Tobi facilitates the recording process further by providing a special view for users where they will be able to concentrate on the text that is being narrated. This view is called Narrator View and can be launched by clicking View->Narrator window or by pressing Ctrl+N. It displays the contents of document on entire screen with a list of relevant controls on the bottom of the window, hiding other components of Tobi like the Audio Editor pane and Toolbars. Additionally, it can be switched to Single phrase mode and can be zoomed according to user’s requirements that makes it most practicable for people with low vision.
The controls presented by Narrator View are listed below:
- Start recording: Begin recording from the input device.
- Stop recording and continue: Wind up audio recorded till now to the current item and start recording for the next item.
- Play/Pause: A toggle button to start or pause the playback.
- Expand selection: Show the sub-items of the higher selection in the Document Structure Trail.
- Narrow selection: Hide the sub-items of the higher selection in the Document Structure Trail.
- Select previous phrase: Select previous item of the document.
- Select next phrase: Select next item of the document.
- Single phrase mode: Show only the highlighted item in the Narrator View.
- Select font: A combo box enabling users to change the font of the text. This change will reflect in the Document pane also.
- Zoom: A slider to magnify or shrink the contents of the document.
The main purpose of session counter is to keep record of total audio inserted in the current session. This tool becomes handy when payments have to be made based on the amount of audio narration or insertion. The last item of the Status bar informs the duration of audio content added in the current session. Any deletions made from the project will be subtracted from this amount automatically.
To reset the session counter, click Audio->Reset session counter on the menu bar or press Ctrl+H. Tobi will reset the session counter to 0. From hereon, any insertion or deletion of audio content will be counted and augmented to it. At the end of the session, you will get the clear picture of the amount of work done.
Audio editing features are a vital part of DAISY book authoring software and Tobi takes utmost care to provide a rich functionality for the same. The sections that follow throw light on the features that assist and enable audio editing.
Marking Cursor Position
You can mark the cursor position on waveform by any of the methods described below:
- Mouse users can simply click on a location on the waveform.
- Keyboard users should play the audio of the item by pressing Space and press Space again at the desired location.
Thereafter, you can use the Preview command to check the accuracy of the position or use Step back and Step forward commands to move back or ahead respectively a very small amount of time.
There are various methods of selecting audio in Tobi. You can select the entire audio corresponding to the item or some portion of it. Use any of the commands listed below to make the desired selection.
- To select entire audio of the item selected in the Document pane, click Audio->Selection->Select all on the menu, press Ctrl+A or use the Select all button of the Audio toolbar. Mouse users can double-click on the waveform to select the contained audio.
- To select the audio content on the left of the marked cursor position, click Audio->Selection->Select left on the menu or press Shift+Home. You may also use the Select left button of the Audio toolbar to achieve the same.
- To select the audio content on the right of the marked cursor position, click Audio->Selection->Select right on the menu or press Shift+End. You may also use the Select right button of the Audio toolbar for the same.
- To select audio corresponding to the previous item, click Audio->Selection->Select previous chunk on the menu bar or press Shift+Ctrl+Alt+Left arrow. Alternatively, you may use the Select previous chunk button of the Audio toolbar.
- To select the audio content of next item, click Audio->Selection->Select next chunk on the menu or press Shift+Ctrl+Alt+Right arrow. Another method to execute this command is by using the Select next chunk button of the Audio toolbar.
- If you wish to select any portion of audio within the waveform, use Begin selection and End selection commands from the submenu of Audio->Selection. Other faster methods to accomplish the same are:
- Keyboard users: Start playback by pressing Space. Press Ctrl+[ to mark the beginning of selection at the desired location. Press Ctrl+] to mark the end of the selection.
- Mouse users: Click at a desired location on the waveform to begin the selection and use Shift+Click to end the selection. Alternatively, you can make the selection by pressing the left mouse button and holding while dragging it to a position where the selection should end.
Tobi will display the selected audio of the waveform in different color in the Audio Editor pane. The following figure illustrates how audio selection will look in Tobi.
To hear the contents of the audio selection, press Space. Please note here that if an audio selection is marked, the Play command will play the audio contents of the selection only. To hear the entire audio corresponding to an item, you should clear the selection first. Audio selection can be deselected by clicking Audio->Selection->Clear selection on the menu, by pressing Ctrl+D, or by using the Clear selection button of the Audio toolbar. Please note that if you execute a command to navigate to another item, audio selection will be cleared automatically.
You can also use the Preview commands to preview audio just before or just after the left boundary of the selection as described in the following section.
You can preview the audio content before and after the marked cursor position or beginning of audio selection by using the following commands:
- To preview audio just before the cursor position, click Audio->Playback->Preview before on the menu or press Shift+Ctrl+P. You may also use the Preview before button of the Audio toolbar for the same.
- To preview audio just after the cursor position, click Audio->Playback->Preview after on the menu or press Ctrl+P. Another alternative to execute this command is by using the Preview after button on the Audio toolbar.
In case of audio selection, these commands will preview audio immediately before and after the beginning of audio selection.
Step Back and Forward
You can move the marked cursor position forward or backward by a very small amount of time by using the Step forward and Step back commands as described below.
- Click Audio->Navigation->Step back.
- Press Ctrl+Left arrow.
- Use Step back button of the Audio toolbar.
- Click Audio->Navigation->Step forward.
- Press Ctrl+Right arrow.
- Use Step forward button of the Audio toolbar.
The above commands move the cursor by the time specified in the preference AudioWaveform_JumpTimeStep.
You can also move the cursor by a larger amount of time by using the following commands that move the cursor by the time specified in the preference AudioWaveform_JumpTimeStepX:
- Step back larger interval): Click Audio->Navigation->Step back (more) or press Shift+Ctrl+Left Arrow.
- Step forward larger interval: Click Audio->Navigation->Step forward (more) or press Shift+Ctrl+Right Arrow.
Commands for Navigating Within or Among Waveforms
Apart from the Step back and Step forward commands that enable motion of audio cursor within the waveform, the following commands can be used to navigate within and among waveforms:
- To move to the beginning of the current waveform, click Audio->Navigation->Go to Start on the menu or press Home. Alternatively, you can use the Go to Start button of the Audio toolbar.
- To move the cursor to the end of the current waveform, click Audio->Navigation->Go to End on the menu or press End. You may also use the Go to End button of the Audio toolbar to achieve the same.
- To go to the waveform prior to the current waveform, click Audio->Navigation->Previous chunk on the menu bar or press Ctrl+Alt+Left arrow. You may also use the Previous chunk button of the Audio toolbar to achieve the same.
- To go to the waveform following the current waveform, click Audio->Navigation->Next chunk on the menu bar or press Ctrl+Alt+Right arrow. Alternatively, you can use the Next chunk button of the Audio toolbar.
Cut, Copy, and Paste
You can perform these operations on the selected audio by following methods:
- To copy the audio selection to the clipboard, click Edit->Copy on the menu, press Ctrl+C, or use the Copy button of the Main toolbar.
- To cut the audio selection (remove it from the current location and copy to the clipboard), click Edit->Cut on the menu, press Ctrl+X, or use the Cut button of the Main toolbar.
- To paste the item from the clipboard at the current location, click Edit->Paste on the menu, press Ctrl+V, or use the Paste button of the Main toolbar.
Tobi will paste the audio content from the clipboard according to the following rules:
- If an audio selection is marked, the audio content from the clipboard will replace the audio slection. This will result in deletion of audio selection and insertion of audio from clipboard in its place.
- If you have marked the cursor position, the audio content from the clipboard will be inserted there.
- If you are at the beginning of the waveform, audio will be inserted prior to any audio content present already.
- If you are at the end of the waveform, audio content from the clipboard will append the audio content present there.
- If the selected item does not have audio corresponding to it, the audio content from the clipboard will be mapped to it.
You can split the audio content both by marking the cursor position or on-the-fly during playback. The split command can be invoked by clicking Audio->Split audio on the menu or by pressing Ctrl+Enter. This command is very useful when you have imported pre-recorded audio content in your project and have to map it to its text equivalent. The process flow is described as follows:
- Import audio file.
- Start playback by pressing Space.
- As soon as you reach the end of audio corresponding to the current text, press Ctrl+Enter. Tobi will split the audio content at the position of audio cursor, and copy the audio content after the split position to the next phrase. Now the keyboard focus will be at the next item, where the audio has been pasted. If the next phrase had some audio content already, it will not be deleted but appended to the copied audio.
- Perform steps 2 and 3 repeatedly till you have mapped the imported audio to the respective items of the document.
You can only delete audio selection in Tobi, and therefore you should select audio by any of the methods described in the section Audio Selection before using the Delete command. After selecting audio, you can delete it by clicking Audio->Delete selected audio on the menu , by pressing Del, or by using the Delete selected audio button of the Audio toolbar.
The audio that you delete will not be removed from the file physically but just delinked from the project. Actual deletion will take place when you run Clean up command. This is done especially to reduce disk I/O operations that would otherwise affect the efficiency of the application.
Editing Audio Externally
You might want to edit the recorded audio with other tools for amplification, normalization, etc. To edit audio externally, do the following:
- Select the audio you wish to export to an external file.
- Click Audio->Edit audio externally on the menu or press Ctrl+J. Tobi will export the audio to a WAV file and display its name in the dialog box just opened. Please do not close the dialog box till the process is finished.
- Click on the Open file externally button that will open Windows File Browser displaying the exported WAV file.
- Now, you can make the modifications in this file using other tools like Audacity, etc.
- After you have done the modifications, go back to the application window of Tobi.
- Click on the OK button to import the modified audio in place of the exported audio.
Please note that it is important to keep the dialog box opened till the process of external editing is complete; otherwise, Tobi will not make automatic replacement.
Tobi possesses the capability of integrating audio processing libraries. Currently, there is a preliminary support for the functions listed below, which will be replaced by third-party libraries in future to provide high-quality audio processing.
- Edit audio externally: Facilitates you in performing audio processing using an external tool as described in the previous section.
- Slow down: Expands the audio content producing audio at slower rate.
- Speed up: Contracts the audio content to produce audio at faster rate.
- Normalize: Performs audio normalization on selected audio.
- Amplify: Intensifies the audio content to make it more audible.
You can access these commands from the Audio preferences submenu under the Audio menu. Tobi uses a specific rate for the Amplify, Speed up, and Slow down commands, which can be modified to suit your requirements using the Preferences dialog.
You can modify the audio settings used by Tobi by using the Audio Settings dialog, which can be invoked by clicking Audio->Audio settings on the menu. The following settings can be modified using this dialog box:
- Playback: The output sound device (primary sound driver) used by Tobi.
- Recording: The input sound device (primary sound capture driver) used by Tobi.
- TTS: The default voice used for text to speech conversion.
- Synthetic voice mapping: Opens a pop-up text box where you can enter the configuration mark-up for mapping the XML elements to different synthetic voices. For example, if you wish to choose a different voice for reading headings and paragraphs, you can list the headings (h1, h2, h3, etc.) under a synthetic voice and paragraph (p) under another synthetic voice. A sample from the configuration file is given below.
[TTS_VOICE] Microsoft David Desktop
[TTS_VOICE] Microsoft Zira Desktop
After making appropriate selections, click Close to commit the changes to Tobi and return to application window. You can cancel the changes by pressing Esc.Tags: Tobi