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Mixer device

The chip features a digital mixer that routes and mixes the streams below as follows:

inputs

There are 8 streams corresponding to data received by the device from the codecs. They are labelled line0 – line7 in the mixer(4) interface.

outputs

There are 8 streams corresponding to data sent by the device to the codecs. They are labelled line0 – line7. Each of them can be individually configured to use any of the external inputs or its corresponding playback stream as source. Additionally, outputs line0 and line1 can be configured to use mon0 or mon1 as sources.

monitor

There are 2 streams that can be configured to contain any linear superposition of any of the 10 playback and 10 external input streams. They are labelled mon0 and mon1. From the mixer's point of view they are input streams, so they can be used as sources of output streams. This feature is specific to Envy24 based cards.

playback

There are 10 streams corresponding to samples transferred from the host to the device. They are labelled play0 – play9. From the mixer's point of view they are input streams, so they are usable as sources of output streams.

record

There are 12 streams corresponding to samples transferred from the device to the host. They are not controllable by the mixer. Streams 0 to 7 are hardwired to external inputs line0 – line7 and streams 10 and 11 are hardwired to mon0 and mon1.

Playback and record data formats

Both playback and record use linear encoding. Samples are represented by 32-bit signed numbers in little endian order. Only the first 24 most significant bits are used. On Envy24-based cards, playback uses 10 channels and record uses 12 channels, while on Envy24HT-based cards the number of streams depend on the number of codecs physically present on the card.