To prepare files for the InterSoft IQTalk runtime system, the Sonic Foundry Batch Converter 5.0 takes the master .wav format and converts it to the .ivc file ADPCM format.
Figure 5-1. .wav to .ivc Batch Conversion Process
To prepare files for the VoiceXML Browser runtime system, the Sonic Foundry Batch Converter 5.0 takes the master .wav format and converts it to the runtime .wav file format.
Figure 5-2. .wav to runtime .wav Batch Conversion Process The batch script, Intervoice Example Batch Script, automates most of the postprocessing steps for voice files. The sample script shows how most of the steps can be automated in a single batch process using the Batch Converter. (The Intervoice Example Batch Script is for demonstration purposes. You must modify the preset parameters to suit the specific circumstance.)
Master Format
11 KHz, 16-bit Sonic Foundry
Batch Converter
Mono.wav
InterSoft IQTalk Format 8 KHz, 4-bit ADPCM .ivc
Master Format
11 KHz, 16-bit Sonic Foundry
Batch Converter
Mono.wav
VoiceXML Format 8 KHz, 8-bit A-law/µ-law .wav
60001198, Second Edition Postprocessing 5-3 Batch Converter Overview
Downloading the Batch Converter
Sony Pictures Digital Media offers periodic updates to the Batch Converter software. Intervoice recommends that you check their Web site. You can download the Batch Converter from Sony Pictures Digital Media at:
http://mediasoftware.sonypictures.com/download/step2.asp?DID=339& #Return/
Be sure to register your copy of the Batch Converter to obtain technical support. See “Installing the Sonic Foundry Batch Converter” on page 2-6.
Note Sound Forge 7.0 users should contact Intervoice
Customer Support if the serial number supplied with their copy of Sound Forge 7.0 fails to enable the Batch Converter 5.0.
Using the Sample Batch Script
The batch script described below is available on the Intervoice Web site at www.intervoice.com/support/techinfo/voicerecording.
To use the sample batch script in the Batch Converter 5.0, follow these steps:
1 Open the Batch Converter.
2 Select File > Open Script. The Open dialog box appears. 3 Navigate to the Intervoice Example Batch Scriptfile, and click
Open to install the batch script.
The Intervoice Example Batch Script creates 32 KBps compressed messages for µ-law playback and –12 dB volume normalization. You may obtain other options, such as µ-law playback, different volumes, and 32 KB compression, by editing the script in the Sonic Foundry Batch Converter.
The Intervoice Example Batch Script is for demonstration purposes. You must modify the preset parameters to suit the specific circumstance.
5-4 Sound Forge and the Intervoice System Audio File Guide 60001198, Second Edition
Converting the .wav Files to Runtime Format Overview
A series of transformational steps is required to convert a .wav file into the runtime file format. All of these steps can be automated into a single batch process in the Batch Converter. The Batch Converter can apply this process to a large number of master .wav files in a single step, creating a set of runtime files, one for each master .wav file.
To convert a master .wav file into a runtime file, the Batch Converter must perform a specific set of processes in a specific order on the original .wav master file. In version 5.0, Sonic Foundry calls these steps plug-ins (presets in Sound Forge 4.5). The final script is called a plug- in chain. The basic recording process provides a clean audio signal digitized to the system’s hard drive in .wav file format. However, there are several other processing steps that must be applied to an audio file after it is recorded, but before it can be placed on an Intervoice system. The Intervoice sample Batch Converter postprocessing procedures are described below:
DC Offset removal
Removes any DC offset before messages are compressed. Most sound cards have some DC offset that can affect the compression process.
Front and Back silence trimming with 20-ms fades
Removes excess silence on the front and back of messages to tighten the message delivery. Generally the messages are trimmed to 20 milliseconds or less of silence on both ends. Noise at the beginning or end of messages (such as mouse or keyboard clicks) causes the auto-trimming process to trim too early or too late, leaving extra silence in the message. These messages must be hand-trimmed. Front and Back silence buffering with 50-ms buffers
Prevents the destabilization of the ADPCM decoder when two messages are played back to back. Once the arbitrary silences are trimmed from the message, this step places a standard
50-millisecond silence buffer on the beginning and end of every message.
Message level normalization
Converts all the messages in a single application to a single standard volume level, so that listeners hear every message at the same volume.
8 KHz resampling
Converts the 11.025 KHz sample rate of the master file to an 8 KHz sampling rate.
60001198, Second Edition Postprocessing 5-5 Batch Converter Overview
Equalization
Performs the frequency manipulation required to make high-quality message playback over telephone lines.
ADPCM compression for A-law playback and Intervoice formatting Compresses the linear format to ADPCM to reduce the size of the message files on the Intervoice system. This step is where you specify whether a message is to be played as µ-law or A-law, or to be compressed to 32 KB.
5-6 Sound Forge and the Intervoice System Audio File Guide 60001198, Second Edition