Microsoft® Windows Media® Encoder 9 Series and the Microsoft Windows Media Audio 9 Professional codec enable you to create audio or video files that contain up to eight channels in a number of different configurations. After creating the files, users can enjoy a true surround-sound experience by playing the files using Microsoft Windows Media Player 9 Series, through a sound card that supports multichannel audio, and a speaker system that includes up to seven speakers and one sub-woofer.
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Abstract
Describes how to use the Microsoft Windows Media Audio 9 Professional Channel Mask Mapping Tool, which enables you to change the mapping of the channels in an encoded Windows Media audio file to support a number of different speaker layouts. This is useful because a Windows Media file with multiple surround-sound audio channels will only play correctly if the channel mapping on a user's computer is same as that of the file.
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In order to properly play a multichannel file, the user's system must be capable of playing back with the same channel mapping that was used to create the file. This article describes how to use the Microsoft Windows Media Audio 9 Professional Channel Mask Mapping Tool to modify encoded multichannel files or to create new files to support different speaker configurations.
A multichannel file contains a channel mask that maps each channel to a sound card output. When a user plays a multichannel file, the mask ensures that the audio plays correctly through a standard speaker configuration. When setting up an encoding session, you determine the layout of the mask in a file by how you set up your source files, or by how you create your multichannel WAV file. After you have encoded a Windows Media audio file, you can change the mapping with the Windows Media Audio 9 Professional Channel Mask Mapping Tool.
Channel-mask standards were established so that multichannel content would map to the correct speaker outputs, regardless of the playback system. Standards also make setup easier for users. Configurations can consist of from four to eight speakers that include front-left (FL), front-right (FR), and center (C) speakers; back-left (BL), back-right (BR), and back-center speakers; speakers on side-left (SL) and side-right (SR); and a low-frequency enhancement (LFE) or sub-woofer speaker. Eight channel systems can also include two additional front speakers.
Configuration names consist of two numbers: the first number indicates the number of normal-range speakers; the second number indicates whether the configuration includes an LFE speaker. For example, a 5.1 system consists of five normal-range speakers plus one LFE speaker.
The 5.1 and 7.1 Dolby configurations make use of SL and SR speakers, while the 5.1 DTS system, the default used by Windows Media, places the side speakers in the back (BL and BR). The 7.1 SDDS configuration, which is the default used in Microsoft Windows® XP, makes use of five front speakers. Although this configuration is used commonly in large commercial theaters, it may not provide the best experience in a home system.
The Windows Media Audio 9 Professional Channel Mask Mapping Tool enables you to change the channel mapping in a file that has already been encoded. You can also use the tool to create multiple channel-mask versions of one file. For example, you could convert a file with the 7.1 SDDS configuration to the 7.1 Dolby configuration that places the front-left-of-center (FLOC) and front-right-of-center (FROC) speakers on side-left (SL) and side-right (SR). Then, in addition to the SDDS version, you could offer the Dolby version, which is more appropriate for a home system.
Open a command prompt, and change to the directory in which the Windows Media Audio 9 Professional Channel Mask Mapping Tool (WMCME.exe) was installed. The default installation directory is %systemdrive%\Programs Files\Windows Media Components\WMCME.
To run WMCME.exe, type the following at the command line, and then press ENTER:
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