Tutorial 5

About sound

An integral part of every video is the soundtrack. To use audio in DVP effectively, you need to understand these concepts:

Channels The number of output devices (such as speakers) to which sound can be directed. Mono plays the same audio through both channels, while stereo has two separate channels. Typically on the computer, stereo is only used for high-fidelity music applications.
Sample size The amount of data in each sample of audio. Most desktop applications use 8-bit sampling; 16-bit sampling is equivalent to CD-quality sound.

Sample rate The number of audio samples per second, expressed in kilohertz (kHz). The higher the sample rate, the better the sound quality (and the more memory required). DVP works with audio files sampled at 11.025kHz, 22.05kHz, and 44.1kHz.

Higher-quality audio is not always your best choice. For example, an audio track that is 44.1kHz, 16-bit stereo requires 16 times the space of the same audio sampled at 11.025kHz, 8-bit mono. Because the amount of data in an audio stream can drastically reduce the playback performance of the video, you should always use the lowest acceptable quality for audio. Use the following general rules to begin with, but always test to be sure you achieve the quality you want:

For sound effects, choose 11.025kHz 8-bit mono.
For voiceovers, choose 22.05kHz 8-bit mono.
For music, choose 44.1kHz 8-bit stere

   
Top

Adjusting the volume on an audio clip
You can adjust the volume throughout an audio clip so that the volume is increased or decreased at different points in the audio portion of a project. This is especially useful when you want the audio portion of a project to fade in or out at different times during a video sequence.

To set volume points in an audio clip:

1 Select the audio clip for which you want to establish volume settings.

2 Place the cursor on a vertical point of the clip, and double click to set the volume point. The higher the point you place the adjustment, the higher the volume; the lower the point, the lower the volume. Be sure to place the cursor at the correct time of clip where you want the volume adjustment to take place.
Top

Audio Properties
Don’t output audio If selected, the file will be built without audio.
Audio Settings Opens the Audio Settings dialog box where you can set the type of audio compression used in the build.
OK Saves output settings and closes the dialog box.
Apply Applies the settings without closing the dialog box.
Cancel Closes the dialog box without saving output settings.
Help Audio Properties
File menu / Build/Settings / Settings / Audio tab

Click to display help for the Video Properties and Audio Properties

Option Description

Don’t output audio If selected, the file will be built without audio.

Audio Settings Opens the Audio Settings dialog box where you can set the type of audio compression used in the build.
OK Saves output settings and closes the dialog box.
Apply Applies the settings without closing the dialog box.
Cancel Closes the dialog box without saving output settings.

Help Opens the dialog box Help topic.


Auto Gain Control audio
filter properties


Automatically boosts the volume to a more acceptable sound level when audio clip was originally recorded at a low level. There are no effects options are available for this filter.