Support for Double Rate Audio
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AC ’97 Programmer’s Reference Manual 47
7 Support for Double Rate Audio
The ICH5 AC’97 controller has the capability of supporting a stereo 96 kHz stream using the
AC’97 Double Rate Audio (DRA) support. This capability is enabled by programming the
controller to use four-channel mode, which will place data on slots 3, 4, 7, and 8. A codec that is
capable of treating the stream as PCM Left, Right, Left+1, and Right+1 data will interpret this as
96 kHz stream, providing higher quality audio.
Note that the current AC ’97 Component Specification, Revision 2.3 provides support for Double
Rate on slots 3, 4, 10, and 11, a mode that is not supported by the ICH5 controller. Codecs will
need to additionally accept data on slots 3, 4, 7, and 8 to utilize DRA with the ICH5.