---
name: "oss_cmpci"
section: "7"
platform: "linux"
package: "oss4-base"
version: "4.2-build2010-2"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/oss_cmpci"
---

# oss\_cmpci(7)

CMedia CMI8738/8768 audio driver.

## NAME

**oss\_cmpci** - CMedia CMI8738/8768 audio driver.

## DESCRIPTION

**Open Sound System driver for CMedia Electronics CMI8738/8768 audio**

**CMI87xx device characteristics:**

- •

  **8/16 bit playback/record**

- •

  **mono/stereo/4ch/5.1ch playback**

- •

  **8KHz to 48Khz sample rate.**

### MIXER PANEL

**The CMedia chip provides some unique features that are set up** **by the Mixer chip. Running ossxmix will display the CMI8738 mixer** **panel.**

**Most of the sliders and buttons are self evident. However there** **are some options that need explaining:**

**Dual Dac: Enabling this button sets the CMPCI device as two** **separate output devices with /dev/dsp1 audio going to the front and** **/dev/dsp0 going to the rear outputs. Separate audio streams can** **be send to the device simultaneously.**

**Speaker Mode: The audio can be sent just to the front speakers or** **it can be sent simultaneously to all speakers in the "Spread" mode.**

**AC3 passthrough only works on Models 037 and higher. This is because of** **a hardware bug in the earlier models so check the model number** **(ossinfo -a).**

**SPDIF:**

- •

  **Enable will enable SPDIF output.**

- •

  **Rec will allow you to record from the SPDIF device. Note that when** **you have SPDIF recording enabled, you cannot play 4/6 channel audio.**

- •

  **Polarity - certain models require you to flip the bit otherwise you** **get distorted audio.**

- •

  **IMon - monitor input via SPDIF in.**

- •

  **Optical - sets the SPDIF to Optical (TOSLINK) or RCA Jacks interface.**

## OPTIONS

**None**

## FILES

**/etc/oss4/conf/oss\_cmpci.conf Device configuration file**

## AUTHOR

**4Front Technologies**