Autodesk 64006-051108-9001 User Guide - Page 85

The Audio Tab 77 Using Audio Filters After you create and capture your audio, there are several things you can do to optimize your audio for streaming delivery. Noise in the audio track often degrades the final compression of the audio, which results in more artifacts/larger files. The primary goal of most of Cleaner audio filters is to remove unwanted noise to improve the audio compression. There are also some audio processing features, such as the Dynamic Range filter and Reverb, to improve the subjective quality of the audio. The Noise Removal filter helps clean up hiss, noise and other unwanted sounds. Careful use of the Noise Gate, Low Pass, High Pass and Notch filters can also help improve a noisy signal prior to compression. Dynamic Range compression can increase the apparent volume of audio, as well as limit peaks, which often works well for Web audio. Likewise, many audio producers add a slight amount of reverb to make the audio sound richer and more pleasant. When making audio or movies for the Web, normalize the volume to about 90% if you do not use the Dynamic Range filter. This helps reduce the peak volume and prevent the audio from breaking up during loud passages when it is encoded. Using Cleaner audio filters is often just a matter of choosing the most applicable presets with a few commonly used filters, such as Noise Removal. However, for difficult material, experimentation with the Custom controls of the audio filters may be helpful. Sample Rate Enable to set the sample rate (the number of samples per second) used to reproduce the audio. The highest frequency that can be reproduced is half the sample rate. Some common sample rates are: • 32 kHz - For lower data rate audio • 44.1 kHz - For "cd quality" audio • 48 kHz - Required for DVD Data Rate (only for MP3, MPEG Layer 1, MPEG Layer 2) Set the data rate. The higher the data rate the higher the quality and the larger the output file. Depth Enable to set the depth, or sample size for the encoded audio track. Sample size determines the accuracy of each sound sample of the audio track. Greater depth equals better quality at the expense of larger file size.